Public issue detail

Runaway CPU investigation for dockerd: socket churn at __schedule

dockerd is stuck in a likely socket churn loop: 100.00% of sampled CPU passed through __schedule, with repeated thread backtraces show 1 thread(s) around 0x000056124fea7023 in ?? () and 1 thread(s) around 0x000056124fea7023 in ?? ().

highpackage: docker.iosource: docker.ioscore: 106reports: 2patch attempt readyrelated upstream: covered-by-review review

Last seen: 2026-05-13 18:42 UTC. Public JSON: /v1/issues/019de7d3-3c01-71f1-9dbd-ce696226a958

Patch related to upstream review

This diff is preserved for inspection, but a related source-family upstream review is the current handoff. Use the retained patch as evidence only; do not open a duplicate review from this artifact.

best patchcreated: 2026-05-13 18:14 UTCvalidation: readyrelated upstream: covered-by-review review

dockerd likely remains stuck in a socket churn loop. A diagnosis report and patch proposal were created locally.

Suggested subject

libcontainerd: bound containerd event stream reconnects

Commit message.

Keep containerd task event stream recovery inside one goroutine and handle closed event channels explicitly. If the stream drops, dockerd now cancels the old subscription, waits for containerd to report ready, and delays briefly before resubscribing instead of starting a replacement goroutine immediately.

Refinement round 1 addresses the review finding by rewording the source comment and patch explanation to describe reconnect goroutine churn, not accumulated event processors.

Problem. dockerd is stuck in a likely socket churn loop: 100.00% of sampled CPU passed through __schedule, with repeated thread backtraces show 1 thread(s) around 0x000056124fea7023 in ?? () and 1 thread(s) around 0x000056124fea7023 in ?? ().

How this patch connects to the issue.

Fixer observed `dockerd` with 185 threads, mostly blocked in futex waits, with strace showing repeated `futex`, `nanosleep`, `epoll_pwait`, `waitid`, and some nonblocking socket reads. This was observed by Fixer and not independently reproduced.

The cautious code-level connection is the libcontainerd task event stream, which is the daemon’s long-lived containerd event subscription for task lifecycle messages. Its recovery path spawned a replacement `processEventStream` goroutine on recoverable stream errors and did not distinguish closed event/error channels from real events.

This patch keeps reconnect handling in the existing goroutine, explicitly treats closed channels as a reconnect condition, preserves the existing `waitServe` readiness check, and adds a short timer before resubscribing. It follows the local `containerd/log`, `context.WithCancel`, and timer conventions already used in this subsystem. I added a short comment documenting that reconnects stay in one goroutine to avoid replacement-goroutine churn.

The expected effect is to reduce event-stream reconnect churn when the containerd event subscription repeatedly fails or closes.

Files touched

  • engine/libcontainerd/remote/client.go

Validation

  • Fixer marked this proposal `ready` on 2026-05-13 18:14 UTC.
  • The underlying issue cluster has 2 report(s) and was last seen 2026-05-13 18:42 UTC.
  • The published diff touches engine/libcontainerd/remote/client.go.
  • Ran `cd engine && make test-unit TESTDIRS=./libcontainerd/remote` from the workspace root. It did not reach tests: Docker failed during build setup with `ERROR: mkdir /root/.docker: read-only file system`. Ran `cd engine && HOME=/tmp GOCACHE=/tmp/go-cache GOPATH=/tmp/go go test ./libcontainerd/remote`. It failed because module lookup is disabled by `-mod=readonly` and this Debian source tree does not provide the needed modules in normal module mode. Ran `cd engine && HOME=/tmp GOCACHE=/tmp/go-cache GOPATH=/tmp/go GOFLAGS=-mod=vendor go test ./libcontainerd/remote`. It failed with inconsistent vendoring because `vendor/modules.txt` marks many modules explicit while `engine/go.mod` only declares the module. Ran a GOPATH/vendor fallback via `/tmp/gopath`; it failed because this Debian source snapshot does not include required containerd dependency source directories under `engine/vendor`. Independent reproduction attempt: `pgrep -a dockerd` found no running daemon to attach a bounded `strace` to. I did not start a real daemon as a reproducer because that would alter host state. Confidence remains `observed`. `gofmt -w engine/libcontainerd/remote/client.go` and `git diff --check` passed.

Related upstream review

This retained diff belongs to an issue family already tracked upstream as https://github.com/moby/moby/pull/52643 (covered-by-review review; 1 related row).

diff --git a/engine/libcontainerd/remote/client.go b/engine/libcontainerd/remote/client.go
index 3d3ec63..cf88ad2 100644
--- a/engine/libcontainerd/remote/client.go
+++ b/engine/libcontainerd/remote/client.go
@@ -574,6 +574,73 @@ func (c *client) processEvent(ctx context.Context, et libcontainerdtypes.EventTy
 	})
 }
 
+func (c *client) processEventEnvelope(ctx context.Context, ev *apievents.Envelope) {
+	v, err := typeurl.UnmarshalAny(ev.Event)
+	if err != nil {
+		c.logger.WithError(err).WithField("event", ev).Warn("failed to unmarshal event")
+		return
+	}
+
+	c.logger.WithField("topic", ev.Topic).Debug("event")
+
+	switch t := v.(type) {
+	case *apievents.TaskCreate:
+		c.processEvent(ctx, libcontainerdtypes.EventCreate, libcontainerdtypes.EventInfo{
+			ContainerID: t.ContainerID,
+			ProcessID:   t.ContainerID,
+			Pid:         t.Pid,
+		})
+	case *apievents.TaskStart:
+		c.processEvent(ctx, libcontainerdtypes.EventStart, libcontainerdtypes.EventInfo{
+			ContainerID: t.ContainerID,
+			ProcessID:   t.ContainerID,
+			Pid:         t.Pid,
+		})
+	case *apievents.TaskExit:
+		c.processEvent(ctx, libcontainerdtypes.EventExit, libcontainerdtypes.EventInfo{
+			ContainerID: t.ContainerID,
+			ProcessID:   t.ID,
+			Pid:         t.Pid,
+			ExitCode:    t.ExitStatus,
+			ExitedAt:    protobuf.FromTimestamp(t.ExitedAt),
+		})
+	case *apievents.TaskOOM:
+		c.processEvent(ctx, libcontainerdtypes.EventOOM, libcontainerdtypes.EventInfo{
+			ContainerID: t.ContainerID,
+		})
+	case *apievents.TaskExecAdded:
+		c.processEvent(ctx, libcontainerdtypes.EventExecAdded, libcontainerdtypes.EventInfo{
+			ContainerID: t.ContainerID,
+			ProcessID:   t.ExecID,
+		})
+	case *apievents.TaskExecStarted:
+		c.processEvent(ctx, libcontainerdtypes.EventExecStarted, libcontainerdtypes.EventInfo{
+			ContainerID: t.ContainerID,
+			ProcessID:   t.ExecID,
+			Pid:         t.Pid,
+		})
+	case *apievents.TaskPaused:
+		c.processEvent(ctx, libcontainerdtypes.EventPaused, libcontainerdtypes.EventInfo{
+			ContainerID: t.ContainerID,
+		})
+	case *apievents.TaskResumed:
+		c.processEvent(ctx, libcontainerdtypes.EventResumed, libcontainerdtypes.EventInfo{
+			ContainerID: t.ContainerID,
+		})
+	case *apievents.TaskDelete:
+		c.logger.WithFields(log.Fields{
+			"topic":     ev.Topic,
+			"type":      reflect.TypeOf(t),
+			"container": t.ContainerID,
+		}).Info("ignoring event")
+	default:
+		c.logger.WithFields(log.Fields{
+			"topic": ev.Topic,
+			"type":  reflect.TypeOf(t),
+		}).Info("ignoring event")
+	}
+}
+
 func (c *client) waitServe(ctx context.Context) bool {
 	t := 100 * time.Millisecond
 	delay := time.NewTimer(t)
@@ -607,105 +674,83 @@ func (c *client) waitServe(ctx context.Context) bool {
 }
 
 func (c *client) processEventStream(ctx context.Context, ns string) {
-	// Create a new context specifically for this subscription.
-	// The context must be cancelled to cancel the subscription.
-	// In cases where we have to restart event stream processing,
-	//   we'll need the original context b/c this one will be cancelled
-	subCtx, cancel := context.WithCancel(ctx)
-	defer cancel()
+	for {
+		if ctx.Err() != nil {
+			c.logger.WithError(ctx.Err()).Info("stopping event stream following graceful shutdown")
+			return
+		}
 
-	// Filter on both namespace *and* topic. To create an "and" filter,
-	// this must be a single, comma-separated string
-	eventStream, errC := c.client.EventService().Subscribe(subCtx, "namespace=="+ns+",topic~=|^/tasks/|")
+		// Create a new context specifically for this subscription.
+		// The context must be cancelled to cancel the subscription.
+		subCtx, cancel := context.WithCancel(ctx)
 
-	c.logger.Debug("processing event stream")
+		// Filter on both namespace *and* topic. To create an "and" filter,
+		// this must be a single, comma-separated string
+		eventStream, errC := c.client.EventService().Subscribe(subCtx, "namespace=="+ns+",topic~=|^/tasks/|")
 
-	for {
-		select {
-		case err := <-errC:
-			if err != nil {
+		c.logger.Debug("processing event stream")
+
+		restart := false
+		for !restart {
+			select {
+			case err, ok := <-errC:
+				if !ok {
+					c.logger.Warn("containerd event error channel closed")
+					restart = true
+					break
+				}
+				if err == nil {
+					c.logger.Debug("containerd event error channel returned nil error")
+					restart = true
+					break
+				}
 				errStatus, ok := status.FromError(err)
-				if !ok || errStatus.Code() != codes.Canceled {
-					c.logger.WithError(err).Error("Failed to get event")
-					c.logger.Info("Waiting for containerd to be ready to restart event processing")
-					if c.waitServe(ctx) {
-						go c.processEventStream(ctx, ns)
+				if ok && errStatus.Code() == codes.Canceled {
+					if ctx.Err() != nil {
+						c.logger.WithError(ctx.Err()).Info("stopping event stream following graceful shutdown")
+						cancel()
 						return
 					}
+					c.logger.WithError(err).Debug("containerd event stream canceled")
+					restart = true
+					break
 				}
-				c.logger.WithError(ctx.Err()).Info("stopping event stream following graceful shutdown")
-			}
-			return
-		case ev := <-eventStream:
-			if ev.Event == nil {
-				c.logger.WithField("event", ev).Warn("invalid event")
-				continue
+				c.logger.WithError(err).Error("Failed to get event")
+				restart = true
+			case ev, ok := <-eventStream:
+				if !ok {
+					c.logger.Warn("containerd event stream closed")
+					restart = true
+					break
+				}
+				if ev == nil || ev.Event == nil {
+					c.logger.WithField("event", ev).Warn("invalid event")
+					continue
+				}
+				c.processEventEnvelope(ctx, ev)
 			}
+		}
+		cancel()
 
-			v, err := typeurl.UnmarshalAny(ev.Event)
-			if err != nil {
-				c.logger.WithError(err).WithField("event", ev).Warn("failed to unmarshal event")
-				continue
-			}
+		c.logger.Info("Waiting for containerd to be ready to restart event processing")
+		if !c.waitServe(ctx) {
+			c.logger.WithError(ctx.Err()).Info("stopping event stream following graceful shutdown")
+			return
+		}
 
-			c.logger.WithField("topic", ev.Topic).Debug("event")
-
-			switch t := v.(type) {
-			case *apievents.TaskCreate:
-				c.processEvent(ctx, libcontainerdtypes.EventCreate, libcontainerdtypes.EventInfo{
-					ContainerID: t.ContainerID,
-					ProcessID:   t.ContainerID,
-					Pid:         t.Pid,
-				})
-			case *apievents.TaskStart:
-				c.processEvent(ctx, libcontainerdtypes.EventStart, libcontainerdtypes.EventInfo{
-					ContainerID: t.ContainerID,
-					ProcessID:   t.ContainerID,
-					Pid:         t.Pid,
-				})
-			case *apievents.TaskExit:
-				c.processEvent(ctx, libcontainerdtypes.EventExit, libcontainerdtypes.EventInfo{
-					ContainerID: t.ContainerID,
-					ProcessID:   t.ID,
-					Pid:         t.Pid,
-					ExitCode:    t.ExitStatus,
-					ExitedAt:    protobuf.FromTimestamp(t.ExitedAt),
-				})
-			case *apievents.TaskOOM:
-				c.processEvent(ctx, libcontainerdtypes.EventOOM, libcontainerdtypes.EventInfo{
-					ContainerID: t.ContainerID,
-				})
-			case *apievents.TaskExecAdded:
-				c.processEvent(ctx, libcontainerdtypes.EventExecAdded, libcontainerdtypes.EventInfo{
-					ContainerID: t.ContainerID,
-					ProcessID:   t.ExecID,
-				})
-			case *apievents.TaskExecStarted:
-				c.processEvent(ctx, libcontainerdtypes.EventExecStarted, libcontainerdtypes.EventInfo{
-					ContainerID: t.ContainerID,
-					ProcessID:   t.ExecID,
-					Pid:         t.Pid,
-				})
-			case *apievents.TaskPaused:
-				c.processEvent(ctx, libcontainerdtypes.EventPaused, libcontainerdtypes.EventInfo{
-					ContainerID: t.ContainerID,
-				})
-			case *apievents.TaskResumed:
-				c.processEvent(ctx, libcontainerdtypes.EventResumed, libcontainerdtypes.EventInfo{
-					ContainerID: t.ContainerID,
-				})
-			case *apievents.TaskDelete:
-				c.logger.WithFields(log.Fields{
-					"topic":     ev.Topic,
-					"type":      reflect.TypeOf(t),
-					"container": t.ContainerID,
-				}).Info("ignoring event")
-			default:
-				c.logger.WithFields(log.Fields{
-					"topic": ev.Topic,
-					"type":  reflect.TypeOf(t),
-				}).Info("ignoring event")
+		// Keep reconnects in this goroutine so a broken stream cannot churn through replacement goroutines.
+		timer := time.NewTimer(100 * time.Millisecond)
+		select {
+		case <-ctx.Done():
+			if !timer.Stop() {
+				select {
+				case <-timer.C:
+				default:
+				}
 			}
+			c.logger.WithError(ctx.Err()).Info("stopping event stream following graceful shutdown")
+			return
+		case <-timer.C:
 		}
 	}
 }

Technical snapshot

This is the clearest retained userspace thread cluster Fixer captured while the process was spinning.

Representative thread backtrace

  • Command: /usr/sbin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock
  • Why Fixer classified it this way: The trace is dominated by socket syscalls, which suggests the process is rapidly retrying or churning through network or IPC work.
  • Thread summary: thread backtraces show 1 thread(s) around 0x000056124fea7023 in ?? () and 1 thread(s) around 0x000056124fea7023 in ?? ()
  • Contention signals: gdb-stderr: gdb: warning: Couldn't determine a path for the index cache directory.
  • Repeated loop: futex -> futex -> futex
  • Top syscalls: futex x193, nanosleep x91, epoll_pwait x26, waitid x14
  • Package: docker.io 28.5.2+dfsg3-2
  • Kernel: 6.17.10+deb14-amd64
  • Distribution: debian
0x000056124fea7023 in ?? ()
0x000056124fe5eef0 in ?? ()
0x00003083cc681960 in ?? ()
0x0000000000000080 in ?? ()
0x0000000000000000 in ?? ()

Possible duplicates

These are suggestions based on sanitized trigram similarity plus structured fields like package, subsystem, classification, and wait site. They are not auto-merged.

dockerd is stuck in a likely socket churn loop: 100.00% of sampled CPU passed through bpf_lsm_file_permission, with repeated thread backtraces show 1 thread(s) around 0x000056124fea7023 in ?? () and 1 thread(s) around 0x000056124fea7023 in ?? ().

highpackage: docker.iosource: docker.ioscore: 106reports: 2patch attempt readysimilarity: 99%

Why this looks related: same classification, same package, same source package, same subsystem, same target, same wait site, very similar public summary

Last seen: 2026-06-10 00:40 UTC. Public page: /issues/019dfd63-6d80-7570-856f-df901ff2167f. Public JSON: /v1/issues/019dfd63-6d80-7570-856f-df901ff2167f

ollama is stuck in a likely timer churn loop: 25.00% of sampled CPU passed through __schedule, with repeated thread backtraces show 1 thread(s) around 0x000055c5c39ed143 in ?? () and 1 thread(s) around 0x000055c5c39ed143 in ?? ().

highscore: 106reports: 1similarity: 79%

Why this looks related: same subsystem, same wait site

Last seen: 2026-06-05 04:27 UTC. Public page: /issues/019d923e-9063-7b13-831f-2476cfee31b3. Public JSON: /v1/issues/019d923e-9063-7b13-831f-2476cfee31b3

ollama is stuck in a likely timer churn loop: 25.00% of sampled CPU passed through fdget, with repeated thread backtraces show 1 thread(s) around 0x000055c5c39ed143 in ?? () and 1 thread(s) around 0x000055c5c39ed143 in ?? ().

highscore: 106reports: 2successful triagesimilarity: 67%

Why this looks related: same subsystem, same wait site

Last seen: 2026-06-04 05:02 UTC. Public page: /issues/019de4bd-5222-7312-bfda-fe64185d7301. Public JSON: /v1/issues/019de4bd-5222-7312-bfda-fe64185d7301

ollama is stuck in a likely timer churn loop: 50.00% of sampled CPU passed through fput, with repeated thread backtraces show 1 thread(s) around 0x000055c5c39ed143 in ?? () and 1 thread(s) around 0x000055c5c39ed143 in ?? ().

highscore: 106reports: 1successful triagesimilarity: 67%

Why this looks related: same subsystem, same wait site

Last seen: 2026-06-06 17:41 UTC. Public page: /issues/019e1d17-4102-7990-9fc5-5b7e6c0f318e. Public JSON: /v1/issues/019e1d17-4102-7990-9fc5-5b7e6c0f318e

ollama is stuck in a likely timer churn loop: 25.00% of sampled CPU passed through do_sys_poll, with repeated thread backtraces show 1 thread(s) around 0x000055c5c39ed143 in ?? () and 1 thread(s) around 0x000055c5c39ed143 in ?? ().

highscore: 106reports: 1similarity: 65%

Why this looks related: same subsystem, same wait site

Last seen: 2026-06-04 06:35 UTC. Public page: /issues/019dde46-63b9-7120-ad03-592b7c01a22b. Public JSON: /v1/issues/019dde46-63b9-7120-ad03-592b7c01a22b

ollama is stuck in a likely timer churn loop: 25.00% of sampled CPU passed through __hrtimer_setup, with repeated thread backtraces show 1 thread(s) around 0x000055c5c39ed143 in ?? () and 1 thread(s) around 0x000055c5c39ed143 in ?? ().

highscore: 106reports: 1similarity: 64%

Why this looks related: same subsystem, same wait site

Last seen: 2026-06-04 11:13 UTC. Public page: /issues/019d85a7-37c6-7671-8000-ffbb4d39e629. Public JSON: /v1/issues/019d85a7-37c6-7671-8000-ffbb4d39e629

Worker outcome summary

This issue has 51 recorded worker attempts. Only ready diffs and ready triage handoffs get dedicated public boards. Diagnosis-only reports and blocked attempts are summarized here so it is easier to see why work stalled.

2 ready patch attempts
46 diagnosis-only reports
3 failed patch attempts

No ready triage handoffs, explained impossible attempts, or other attempt states.

Most common blockers

  • execution (1 attempt)
  • rate-limit (1 attempt)
  • timeout (1 attempt)

Showing the 25 most recent attempts below and summarizing 26 older attempts here. Show all published attempts for this issue.

Published attempts

ready patch attempt

patch

dockerd likely remains stuck in a socket churn loop. A diagnosis report and patch proposal were created locally.

state: readycreated: 2026-05-13 18:14 UTCvalidation: ready
Published session

Prompt

## Plan Pass

You are planning a fixer patch before any edits happen.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. The original pre-edit snapshot is available at `./source` if you need to inspect it. For interpreter processes, plan from the script/application entrypoint evidence first and include the runtime only as a second investigation target unless the evidence proves a runtime bug.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. Inspect the relevant code, nearby callers, project contribution docs, and local helper/compat APIs, but do not edit files in this pass.

Return a short markdown plan with these exact sections:

## Problem
## Evidence Confidence
## Proposed Subject
## Patch Plan
## Risks
## Validation

Classify `## Evidence Confidence` as exactly one of `reproduced`, `observed`, or `inferred`. Use `inferred` only for a no-patch diagnosis/report plan unless you can name the extra evidence you will collect before editing; inferred source patches are blocked by Fixer because they are not pull-request-ready. For `observed` source-patch plans, plan to say in the final `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. The plan must explain how the proposed code change addresses the observed issue evidence, call out any prior Fixer patch that should be improved or replaced, reject awkward control flow such as avoidable `goto` if there is a cleaner bounded alternative, name any local helper APIs or maintainer conventions the patch should follow, and keep the intended maintainer-facing explanation clear enough that someone unfamiliar with the local complaint wording can still follow the fix. In `## Validation`, name the reproducible configure/build/test entrypoint you will try from the workspace root before any focused leaf compile or smoke check, and include one bounded independent reproduction attempt for the collected failure signal when it is safe and cheap. Do not plan to claim `reproduced` unless that reproduction command or test can actually show the failure.

## Patch Pass

You are working on a bounded fixer proposal.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Produce the smallest reasonable patch for the target repository, keep the change upstreamable, prefer the clearest control flow available, and do not keep avoidable `goto` when a simpler structure would read better. Before introducing new file, process, allocation, locking, networking, or platform APIs, inspect nearby code and project contribution docs for existing helpers or compatibility wrappers and use those local patterns unless you can explain why they do not fit. Validate from a reproducible workspace-root entrypoint before falling back to focused leaf commands; if a build or test cannot run, report the exact command, the exact blocker, and any narrower check you ran instead. During validation, also try one bounded independent reproduction of the collected failure signal when it is safe and cheap, such as a failing test, smoke command, perf/strace comparison, or before/after runtime check. Only use `reproduced` if that command or test actually reproduced the failure; otherwise keep `observed` and report the reproduction blocker. The final explanation must connect the observed issue evidence to the actual code change, not just paraphrase the diff. Write like a maintainer is going to read the patch mail cold: explain the bug in plain language, define subsystem-specific jargon the first time you need it, and make the causal story obvious. Explicitly classify evidence confidence as `reproduced`, `observed`, or `inferred`: `reproduced` means you reproduced the failure locally; `observed` means Fixer has direct crash/log/trace evidence but you did not independently reproduce it; `inferred` means the source patch is not pull-request-ready, so do not leave a source diff unless you first gather stronger observed/reproduced evidence; otherwise return a no-patch diagnosis/report. For any source-changing `observed` patch, say explicitly in `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. If you introduce non-obvious state translation, index remapping, or backend split logic, add a short source comment that explains the invariant being preserved.

Start by explaining the likely root cause from the collected perf, strace, and /proc evidence. If you cannot land a safe patch, leave a diagnosis that is strong enough for an upstream bug report.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. 

Keep the change narrowly scoped and summarize validation clearly.

In every authoring pass, your final response must start with `Subject: <single-line git commit subject>` and then include these markdown sections exactly:

## Commit Message
A short upstream-friendly explanation of what changed and why. Write it in plain language that a maintainer can follow without local complaint context. If you use subsystem jargon, define it immediately.

## Evidence Confidence
Exactly one word: `reproduced`, `observed`, or `inferred`. Use `reproduced` only when you reproduced the failure locally with a command or test, and include that command/test in `## Validation`. Use `observed` when Fixer has direct crash/log/trace evidence but you did not independently reproduce it. If `## Git Add Paths` lists source files for an `observed` patch, `## Issue Connection` must explicitly say the failure was observed by Fixer and not independently reproduced. Use `inferred` for profiler/strace/indirect evidence; inferred responses may be no-patch diagnoses or reports, but inferred source patches are not pull-request-ready until stronger evidence is gathered.

## Issue Connection
Write this as maintainer-facing patch mail, not as local Fixer notes. Cover four things explicitly in readable sentences: the user-visible symptom or the exact collected signal, the code-level cause or the cautious inference from evidence, the specific change you made, and the expected effect. Do not invent a reproducer, command line, crash, or user-visible failure that is not present in the evidence bundle. If the evidence is direct-but-not-reproduced, say it was observed by Fixer and not independently reproduced. If the evidence is indirect and you did not gather stronger evidence, do not leave a source diff; write a no-patch diagnosis/report instead. Include an explicit effect sentence such as `The expected effect is ...`, `This should reduce ...`, or `This prevents ...` for source patches. If the logic is non-obvious in code, mention that you added a short explanatory comment.

## Git Add Paths
List the repo-relative paths that belong in the final patch, one per line. Use `None` only when you intentionally made no source changes. Include intentionally new files, and do not list generated build artifacts.

## Validation
List the checks you ran, or say clearly that you could not run them. Include the independent reproduction command/test and result when `## Evidence Confidence` is `reproduced`; if reproduction was attempted but blocked, name the exact blocker and keep confidence at `observed` or `inferred`.

Before editing, read the plan at `./plan-output.txt` and follow it unless the code proves part of it wrong. If you change course, say so explicitly in the final write-up instead of silently drifting from the plan.

## Review Pass 1

You are reviewing a freshly generated fixer patch.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Review the first patch pass. The original pre-edit snapshot is available at `./source` for diffing. The workspace currently changes these repo-relative paths: engine/libcontainerd/remote/client.go. Verify that `## Git Add Paths` matches this exact set and that `## Issue Connection` explains every shipped functional file.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. The latest author response is at `./patch-output.txt`. Inspect the current code and changed paths like a strict code reviewer. Focus on correctness, regressions, maintainability, awkward control flow such as avoidable `goto`, missing validation, weak or non-gittable commit message text, and explanations that fail to connect the observed issue evidence to the code change. Also review the maintainer experience: the patch mail should be easy to accept upstream, the user-visible bug should be explained in plain language, subsystem-specific jargon should be defined when first used, and any non-obvious state translation or index remapping in code should have a short explanatory comment. Reject patches that omit `## Evidence Confidence`, use anything other than `reproduced`, `observed`, or `inferred`, or sound more certain than that evidence level allows. Reject patches that claim `reproduced` unless `## Validation` names the concrete reproduction command or test and its result. Reject patches that invent a reproducer, command line, crash, or user-visible failure not present in the evidence bundle; indirect profiler or strace evidence may justify a cautious mitigation, but the author must say it is indirect instead of presenting it as a confirmed upstream bug. Reject patches that introduce generic libc/std APIs when nearby code or project docs provide a local compat/helper API for the same job, unless the author explicitly justifies the exception. Reject validation that only reports a leaf object/syntax build when a project-level configure/build/test entrypoint exists and was not attempted; if a full build cannot run, the author must show the exact failed command and blocker.

Do not apply code changes in this pass.

Return a short markdown review report. The first non-empty line must be exactly one of:

RESULT: ok
RESULT: fix-needed

If you choose `RESULT: fix-needed`, add a `## Findings` section with concrete, actionable items.

## Refinement Pass 1

You are refining a fixer patch after an explicit code review.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Read the latest author response at `./patch-output.txt`. Read the review report at `./review-1-output.txt`. This is refinement round 1. The original pre-edit snapshot is available at `./source` if you need to compare the current patch against it. Re-read the planning pass at `./plan-output.txt` before editing. The workspace currently changes these repo-relative paths: engine/libcontainerd/remote/client.go. Either keep that exact set synchronized with `## Git Add Paths` and `## Issue Connection`, or revert any unintended file before you answer.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. Address the review findings with the smallest reasonable follow-up changes. If the review identifies a runtime or correctness bug in the changed code, you must update the code itself before answering; a metadata-only response is not sufficient. Keep the patch upstream-friendly, use local project helpers and compat APIs when available, avoid awkward control flow when a simpler structure will do, keep the final response gittable, make the maintainer-facing explanation plain and direct, keep `## Evidence Confidence` honest, add short comments for any non-obvious translation or remapping logic, run relevant project-level build/tests from the workspace root before narrower checks when possible, try a bounded independent reproduction command/test if the review or plan shows one is safe, and summarize which review findings you addressed.

In every authoring pass, your final response must start with `Subject: <single-line git commit subject>` and then include these markdown sections exactly:

## Commit Message
A short upstream-friendly explanation of what changed and why. Write it in plain language that a maintainer can follow without local complaint context. If you use subsystem jargon, define it immediately.

## Evidence Confidence
Exactly one word: `reproduced`, `observed`, or `inferred`. Use `reproduced` only when you reproduced the failure locally with a command or test, and include that command/test in `## Validation`. Use `observed` when Fixer has direct crash/log/trace evidence but you did not independently reproduce it. If `## Git Add Paths` lists source files for an `observed` patch, `## Issue Connection` must explicitly say the failure was observed by Fixer and not independently reproduced. Use `inferred` for profiler/strace/indirect evidence; inferred responses may be no-patch diagnoses or reports, but inferred source patches are not pull-request-ready until stronger evidence is gathered.

## Issue Connection
Write this as maintainer-facing patch mail, not as local Fixer notes. Cover four things explicitly in readable sentences: the user-visible symptom or the exact collected signal, the c

[truncated 4653 bytes]

Response

## Plan Pass

## Problem
Fixer observed `dockerd` with 185 threads, mostly sleeping in futexes, with strace dominated by `futex`, `nanosleep`, `epoll_pwait`, `waitid`, and a few nonblocking `recvmsg(...)=EAGAIN` calls. The bundle labels this as likely socket churn, but the backtrace is stripped and the raw artifact paths are unavailable in this workspace, so the source connection is limited.

The most relevant upstream source path is `engine/libcontainerd/remote/client.go`: `processEventStream` subscribes to containerd task events and, on stream error, waits for `IsServing` and then starts a replacement goroutine immediately. It also reads from `eventStream`/`errC` without checking channel closure. No prior Fixer patch was present beyond the `Fixer baseline` commit.

## Evidence Confidence
observed

## Proposed Subject
`libcontainerd: bound containerd event stream resubscribe churn`

## Patch Plan
Change `engine/libcontainerd/remote/client.go` so containerd event stream recovery stays in one bounded loop instead of recursively launching `go c.processEventStream(...)` on each recoverable stream error.

Handle closed `eventStream` and `errC` channels explicitly with the `ok` receive form. Treat unexpected closure like a stream failure, then wait for `waitServe(ctx)` and apply a small backoff before resubscribing. Avoid `goto`; use a helper or a clear outer `for` loop with per-subscription `context.WithCancel`.

Follow local conventions already in this subsystem: `containerd/log` via `c.logger`, `context.WithCancel` for the subscription lifetime, `time.Timer`/`time.Duration` style as used by `waitServe`, and existing error handling with `status.FromError`, `codes.Canceled`, and `context` cancellation checks.

Add focused unit coverage if a small seam can be introduced without broad refactor: simulate a stream that closes/errors repeatedly and assert the loop does not spawn replacement goroutines or spin without delay. If `containerd.Client.EventService()` is too concrete for clean faking, keep the code change minimal and validate by package build/tests plus a bounded smoke run.

## Risks
The evidence does not prove this exact source path because addresses are stripped and raw artifacts are missing. The patch should be presented as a targeted mitigation for Fixer-observed containerd event stream/socket churn, not as an independently reproduced daemon failure.

Adding backoff can delay event stream recovery slightly after containerd restarts. Keep the delay small and reset it after a successful event receive.

## Validation
From the workspace root, try the upstream test entrypoint first: `cd engine && make test-unit TESTDIRS=./libcontainerd/remote`.

Then run focused checks: `cd engine && go test ./libcontainerd/remote` and `cd engine && go test ./libcontainerd/queue ./libcontainerd/...` if dependency cost is reasonable.

Bounded independent reproduction attempt: before claiming reproduction, run a small targeted test or temporary local harness that forces repeated event stream closure/error and watches for immediate resubscribe churn or goroutine growth. If that cannot be done cleanly, final `## Issue Connection` must say the failure was observed by Fixer and not independently reproduced.

## Patch Pass

Subject: libcontainerd: bound containerd event stream reconnects

## Commit Message
Keep containerd task event stream recovery inside one goroutine and handle closed event channels explicitly. If the stream drops, dockerd now cancels the old subscription, waits for containerd to report ready, and delays briefly before resubscribing instead of spawning a replacement event processor immediately.

## Evidence Confidence
observed

## Issue Connection
Fixer observed `dockerd` with 185 threads, mostly blocked in futex waits, with strace showing repeated `futex`, `nanosleep`, `epoll_pwait`, `waitid`, and some nonblocking socket reads. This was observed by Fixer and not independently reproduced.

The cautious code-level connection is the libcontainerd task event stream, which is the daemon’s long-lived containerd event subscription for task lifecycle messages. Its recovery path spawned a new `processEventStream` goroutine on recoverable stream errors and did not distinguish closed event/error channels from real events.

This patch keeps reconnect handling in the existing goroutine, explicitly treats closed channels as a reconnect condition, preserves the existing `waitServe` readiness check, and adds a short timer before resubscribing. It follows the local `containerd/log`, `context.WithCancel`, and timer conventions already used in this subsystem. I added a short comment documenting the invariant that reconnects stay in one goroutine.

The expected effect is to reduce event-stream reconnect churn and prevent accumulation of event-processing goroutines when the containerd event subscription repeatedly fails or closes.

## Git Add Paths
engine/libcontainerd/remote/client.go

## Validation
Ran `cd engine && make test-unit TESTDIRS=./libcontainerd/remote` from the workspace root. It did not reach tests: Docker failed during the build setup with `ERROR: mkdir /root/.docker: read-only file system`.

Ran `cd engine && HOME=/tmp GOCACHE=/tmp/go-cache GOPATH=/tmp/go go test ./libcontainerd/remote`. It failed because module lookup is disabled by `-mod=readonly` and the Debian source tree does not provide the needed modules in normal module mode.

Ran `cd engine && HOME=/tmp GOCACHE=/tmp/go-cache GOPATH=/tmp/go GOFLAGS=-mod=vendor go test ./libcontainerd/remote`. It failed with inconsistent vendoring because `vendor/modules.txt` marks many modules explicit while `engine/go.mod` only declares the module.

Ran a GOPATH/vendor fallback via `/tmp/gopath`; it failed because this Debian source snapshot does not include the required containerd dependency source directories under `engine/vendor`.

Independent reproduction attempt: `pgrep -a dockerd` found no running daemon to attach a bounded `strace` to. I did not start a real daemon as a reproducer because that would alter host state. Confidence remains `observed`.

`git diff --check` passed.

## Review Pass 1

RESULT: fix-needed

## Findings

- [engine/libcontainerd/remote/client.go:741] The source comment and patch mail overstate the old behavior. The old recovery path did `go c.processEventStream(...)` and then immediately `return`, so it does not by itself “accumulate event processors”; it creates goroutine churn during repeated reconnects. Please reword the comment and `## Issue Connection` / expected effect to say the patch keeps retries in one goroutine and reduces reconnect goroutine churn, without claiming it prevents accumulation of event processors.

- The changed path set is correct: only `engine/libcontainerd/remote/client.go` is modified, and `## Git Add Paths` matches it. The validation section also attempted the documented `make test-unit TESTDIRS=./libcontainerd/remote` entrypoint and reported the exact blocker.

## Refinement Pass 1

Subject: libcontainerd: bound containerd event stream reconnects

## Commit Message
Keep containerd task event stream recovery inside one goroutine and handle closed event channels explicitly. If the stream drops, dockerd now cancels the old subscription, waits for containerd to report ready, and delays briefly before resubscribing instead of starting a replacement goroutine immediately.

Refinement round 1 addresses the review finding by rewording the source comment and patch explanation to describe reconnect goroutine churn, not accumulated event processors.

## Evidence Confidence
observed

## Issue Connection
Fixer observed `dockerd` with 185 threads, mostly blocked in futex waits, with strace showing repeated `futex`, `nanosleep`, `epoll_pwait`, `waitid`, and some nonblocking socket reads. This was observed by Fixer and not independently reproduced.

The cautious code-level connection is the libcontainerd task event stream, which is the daemon’s long-lived containerd event subscription for task lifecycle messages. Its recovery path spawned a replacement `processEventStream` goroutine on recoverable stream errors and did not distinguish closed event/error channels from real events.

This patch keeps reconnect handling in the existing goroutine, explicitly treats closed channels as a reconnect condition, preserves the existing `waitServe` readiness check, and adds a short timer before resubscribing. It follows the local `containerd/log`, `context.WithCancel`, and timer conventions already used in this subsystem. I added a short comment documenting that reconnects stay in one goroutine to avoid replacement-goroutine churn.

The expected effect is to reduce event-stream reconnect churn when the containerd event subscription repeatedly fails or closes.

## Git Add Paths
engine/libcontainerd/remote/client.go

## Validation
Ran `cd engine && make test-unit TESTDIRS=./libcontainerd/remote` from the workspace root. It did not reach tests: Docker failed during build setup with `ERROR: mkdir /root/.docker: read-only file system`.

Ran `cd engine && HOME=/tmp GOCACHE=/tmp/go-cache GOPATH=/tmp/go go test ./libcontainerd/remote`. It failed because module lookup is disabled by `-mod=readonly` and this Debian source tree does not provide the needed modules in normal module mode.

Ran `cd engine && HOME=/tmp GOCACHE=/tmp/go-cache GOPATH=/tmp/go GOFLAGS=-mod=vendor go test ./libcontainerd/remote`. It failed with inconsistent vendoring because `vendor/modules.txt` marks many modules explicit while `engine/go.mod` only declares the module.

Ran a GOPATH/vendor fallback via `/tmp/gopath`; it failed because this Debian source snapshot does not include required containerd dependency source directories under `engine/vendor`.

Independent reproduction attempt: `pgrep -a dockerd` found no running daemon to attach a bounded `strace` to. I did not start a real daemon as a reproducer because that would alter host state. Confidence remains `observed`.

`gofmt -w engine/libcontainerd/remote/client.go` and `git diff --check` passed.

## Review Pass 2

RESULT: ok

The refined patch passes review. `## Git Add Paths` matches the exact changed path set: `engine/libcontainerd/remote/client.go`.

The response keeps `## Evidence Confidence` at `observed`, explicitly says Fixer observed the failure and it was not independently reproduced, and avoids overclaiming beyond the profiler/strace evidence. The issue connection explains the shipped functional file, the event-stream recovery path being changed, and the expected effect.

Validation is acceptable for this environment: the project-level `make test-unit TESTDIRS=./libcontainerd/remote` entrypoint was attempted first and the blocker is stated, followed by narrower Go checks and `git diff --check`. The refined source comment no longer overstates accumulated processors, and I did not find a correctness or maintainability issue that should block the patch.

Diff

diff --git a/engine/libcontainerd/remote/client.go b/engine/libcontainerd/remote/client.go
index 3d3ec63..cf88ad2 100644
--- a/engine/libcontainerd/remote/client.go
+++ b/engine/libcontainerd/remote/client.go
@@ -574,6 +574,73 @@ func (c *client) processEvent(ctx context.Context, et libcontainerdtypes.EventTy
 	})
 }
 
+func (c *client) processEventEnvelope(ctx context.Context, ev *apievents.Envelope) {
+	v, err := typeurl.UnmarshalAny(ev.Event)
+	if err != nil {
+		c.logger.WithError(err).WithField("event", ev).Warn("failed to unmarshal event")
+		return
+	}
+
+	c.logger.WithField("topic", ev.Topic).Debug("event")
+
+	switch t := v.(type) {
+	case *apievents.TaskCreate:
+		c.processEvent(ctx, libcontainerdtypes.EventCreate, libcontainerdtypes.EventInfo{
+			ContainerID: t.ContainerID,
+			ProcessID:   t.ContainerID,
+			Pid:         t.Pid,
+		})
+	case *apievents.TaskStart:
+		c.processEvent(ctx, libcontainerdtypes.EventStart, libcontainerdtypes.EventInfo{
+			ContainerID: t.ContainerID,
+			ProcessID:   t.ContainerID,
+			Pid:         t.Pid,
+		})
+	case *apievents.TaskExit:
+		c.processEvent(ctx, libcontainerdtypes.EventExit, libcontainerdtypes.EventInfo{
+			ContainerID: t.ContainerID,
+			ProcessID:   t.ID,
+			Pid:         t.Pid,
+			ExitCode:    t.ExitStatus,
+			ExitedAt:    protobuf.FromTimestamp(t.ExitedAt),
+		})
+	case *apievents.TaskOOM:
+		c.processEvent(ctx, libcontainerdtypes.EventOOM, libcontainerdtypes.EventInfo{
+			ContainerID: t.ContainerID,
+		})
+	case *apievents.TaskExecAdded:
+		c.processEvent(ctx, libcontainerdtypes.EventExecAdded, libcontainerdtypes.EventInfo{
+			ContainerID: t.ContainerID,
+			ProcessID:   t.ExecID,
+		})
+	case *apievents.TaskExecStarted:
+		c.processEvent(ctx, libcontainerdtypes.EventExecStarted, libcontainerdtypes.EventInfo{
+			ContainerID: t.ContainerID,
+			ProcessID:   t.ExecID,
+			Pid:         t.Pid,
+		})
+	case *apievents.TaskPaused:
+		c.processEvent(ctx, libcontainerdtypes.EventPaused, libcontainerdtypes.EventInfo{
+			ContainerID: t.ContainerID,
+		})
+	case *apievents.TaskResumed:
+		c.processEvent(ctx, libcontainerdtypes.EventResumed, libcontainerdtypes.EventInfo{
+			ContainerID: t.ContainerID,
+		})
+	case *apievents.TaskDelete:
+		c.logger.WithFields(log.Fields{
+			"topic":     ev.Topic,
+			"type":      reflect.TypeOf(t),
+			"container": t.ContainerID,
+		}).Info("ignoring event")
+	default:
+		c.logger.WithFields(log.Fields{
+			"topic": ev.Topic,
+			"type":  reflect.TypeOf(t),
+		}).Info("ignoring event")
+	}
+}
+
 func (c *client) waitServe(ctx context.Context) bool {
 	t := 100 * time.Millisecond
 	delay := time.NewTimer(t)
@@ -607,105 +674,83 @@ func (c *client) waitServe(ctx context.Context) bool {
 }
 
 func (c *client) processEventStream(ctx context.Context, ns string) {
-	// Create a new context specifically for this subscription.
-	// The context must be cancelled to cancel the subscription.
-	// In cases where we have to restart event stream processing,
-	//   we'll need the original context b/c this one will be cancelled
-	subCtx, cancel := context.WithCancel(ctx)
-	defer cancel()
+	for {
+		if ctx.Err() != nil {
+			c.logger.WithError(ctx.Err()).Info("stopping event stream following graceful shutdown")
+			return
+		}
 
-	// Filter on both namespace *and* topic. To create an "and" filter,
-	// this must be a single, comma-separated string
-	eventStream, errC := c.client.EventService().Subscribe(subCtx, "namespace=="+ns+",topic~=|^/tasks/|")
+		// Create a new context specifically for this subscription.
+		// The context must be cancelled to cancel the subscription.
+		subCtx, cancel := context.WithCancel(ctx)
 
-	c.logger.Debug("processing event stream")
+		// Filter on both namespace *and* topic. To create an "and" filter,
+		// this must be a single, comma-separated string
+		eventStream, errC := c.client.EventService().Subscribe(subCtx, "namespace=="+ns+",topic~=|^/tasks/|")
 
-	for {
-		select {
-		case err := <-errC:
-			if err != nil {
+		c.logger.Debug("processing event stream")
+
+		restart := false
+		for !restart {
+			select {
+			case err, ok := <-errC:
+				if !ok {
+					c.logger.Warn("containerd event error channel closed")
+					restart = true
+					break
+				}
+				if err == nil {
+					c.logger.Debug("containerd event error channel returned nil error")
+					restart = true
+					break
+				}
 				errStatus, ok := status.FromError(err)
-				if !ok || errStatus.Code() != codes.Canceled {
-					c.logger.WithError(err).Error("Failed to get event")
-					c.logger.Info("Waiting for containerd to be ready to restart event processing")
-					if c.waitServe(ctx) {
-						go c.processEventStream(ctx, ns)
+				if ok && errStatus.Code() == codes.Canceled {
+					if ctx.Err() != nil {
+						c.logger.WithError(ctx.Err()).Info("stopping event stream following graceful shutdown")
+						cancel()
 						return
 					}
+					c.logger.WithError(err).Debug("containerd event stream canceled")
+					restart = true
+					break
 				}
-				c.logger.WithError(ctx.Err()).Info("stopping event stream following graceful shutdown")
-			}
-			return
-		case ev := <-eventStream:
-			if ev.Event == nil {
-				c.logger.WithField("event", ev).Warn("invalid event")
-				continue
+				c.logger.WithError(err).Error("Failed to get event")
+				restart = true
+			case ev, ok := <-eventStream:
+				if !ok {
+					c.logger.Warn("containerd event stream closed")
+					restart = true
+					break
+				}
+				if ev == nil || ev.Event == nil {
+					c.logger.WithField("event", ev).Warn("invalid event")
+					continue
+				}
+				c.processEventEnvelope(ctx, ev)
 			}
+		}
+		cancel()
 
-			v, err := typeurl.UnmarshalAny(ev.Event)
-			if err != nil {
-				c.logger.WithError(err).WithField("event", ev).Warn("failed to unmarshal event")
-				continue
-			}
+		c.logger.Info("Waiting for containerd to be ready to restart event processing")
+		if !c.waitServe(ctx) {
+			c.logger.WithError(ctx.Err()).Info("stopping event stream following graceful shutdown")
+			return
+		}
 
-			c.logger.WithField("topic", ev.Topic).Debug("event")
-
-			switch t := v.(type) {
-			case *apievents.TaskCreate:
-				c.processEvent(ctx, libcontainerdtypes.EventCreate, libcontainerdtypes.EventInfo{
-					ContainerID: t.ContainerID,
-					ProcessID:   t.ContainerID,
-					Pid:         t.Pid,
-				})
-			case *apievents.TaskStart:
-				c.processEvent(ctx, libcontainerdtypes.EventStart, libcontainerdtypes.EventInfo{
-					ContainerID: t.ContainerID,
-					ProcessID:   t.ContainerID,
-					Pid:         t.Pid,
-				})
-			case *apievents.TaskExit:
-				c.processEvent(ctx, libcontainerdtypes.EventExit, libcontainerdtypes.EventInfo{
-					ContainerID: t.ContainerID,
-					ProcessID:   t.ID,
-					Pid:         t.Pid,
-					ExitCode:    t.ExitStatus,
-					ExitedAt:    protobuf.FromTimestamp(t.ExitedAt),
-				})
-			case *apievents.TaskOOM:
-				c.processEvent(ctx, libcontainerdtypes.EventOOM, libcontainerdtypes.EventInfo{
-					ContainerID: t.ContainerID,
-				})
-			case *apievents.TaskExecAdded:
-				c.processEvent(ctx, libcontainerdtypes.EventExecAdded, libcontainerdtypes.EventInfo{
-					ContainerID: t.ContainerID,
-					ProcessID:   t.ExecID,
-				})
-			case *apievents.TaskExecStarted:
-				c.processEvent(ctx, libcontainerdtypes.EventExecStarted, libcontainerdtypes.EventInfo{
-					ContainerID: t.ContainerID,
-					ProcessID:   t.ExecID,
-					Pid:         t.Pid,
-				})
-			case *apievents.TaskPaused:
-				c.processEvent(ctx, libcontainerdtypes.EventPaused, libcontainerdtypes.EventInfo{
-					ContainerID: t.ContainerID,
-				})
-			case *apievents.TaskResumed:
-				c.processEvent(ctx, libcontainerdtypes.EventResumed, libcontainerdtypes.EventInfo{
-					ContainerID: t.ContainerID,
-				})
-			case *apievents.TaskDelete:
-				c.logger.WithFields(log.Fields{
-					"topic":     ev.Topic,
-					"type":      reflect.TypeOf(t),
-					"container": t.ContainerID,
-				}).Info("ignoring event")
-			default:
-				c.logger.WithFields(log.Fields{
-					"topic": ev.Topic,
-					"type":  reflect.TypeOf(t),
-				}).Info("ignoring event")
+		// Keep reconnects in this goroutine so a broken stream cannot churn through replacement goroutines.
+		timer := time.NewTimer(100 * time.Millisecond)
+		select {
+		case <-ctx.Done():
+			if !timer.Stop() {
+				select {
+				case <-timer.C:
+				default:
+				}
 			}
+			c.logger.WithError(ctx.Err()).Info("stopping event stream following graceful shutdown")
+			return
+		case <-timer.C:
 		}
 	}
 }

ready patch attempt

patch

dockerd likely remains stuck in a socket churn loop. A diagnosis report and patch proposal were created locally.

state: readycreated: 2026-05-13 18:14 UTCvalidation: ready
Published session

Prompt

## Plan Pass

You are planning a fixer patch before any edits happen.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. The original pre-edit snapshot is available at `./source` if you need to inspect it. For interpreter processes, plan from the script/application entrypoint evidence first and include the runtime only as a second investigation target unless the evidence proves a runtime bug.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. Inspect the relevant code, nearby callers, project contribution docs, and local helper/compat APIs, but do not edit files in this pass.

Return a short markdown plan with these exact sections:

## Problem
## Evidence Confidence
## Proposed Subject
## Patch Plan
## Risks
## Validation

Classify `## Evidence Confidence` as exactly one of `reproduced`, `observed`, or `inferred`. Use `inferred` only for a no-patch diagnosis/report plan unless you can name the extra evidence you will collect before editing; inferred source patches are blocked by Fixer because they are not pull-request-ready. For `observed` source-patch plans, plan to say in the final `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. The plan must explain how the proposed code change addresses the observed issue evidence, call out any prior Fixer patch that should be improved or replaced, reject awkward control flow such as avoidable `goto` if there is a cleaner bounded alternative, name any local helper APIs or maintainer conventions the patch should follow, and keep the intended maintainer-facing explanation clear enough that someone unfamiliar with the local complaint wording can still follow the fix. In `## Validation`, name the reproducible configure/build/test entrypoint you will try from the workspace root before any focused leaf compile or smoke check, and include one bounded independent reproduction attempt for the collected failure signal when it is safe and cheap. Do not plan to claim `reproduced` unless that reproduction command or test can actually show the failure.

## Patch Pass

You are working on a bounded fixer proposal.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Produce the smallest reasonable patch for the target repository, keep the change upstreamable, prefer the clearest control flow available, and do not keep avoidable `goto` when a simpler structure would read better. Before introducing new file, process, allocation, locking, networking, or platform APIs, inspect nearby code and project contribution docs for existing helpers or compatibility wrappers and use those local patterns unless you can explain why they do not fit. Validate from a reproducible workspace-root entrypoint before falling back to focused leaf commands; if a build or test cannot run, report the exact command, the exact blocker, and any narrower check you ran instead. During validation, also try one bounded independent reproduction of the collected failure signal when it is safe and cheap, such as a failing test, smoke command, perf/strace comparison, or before/after runtime check. Only use `reproduced` if that command or test actually reproduced the failure; otherwise keep `observed` and report the reproduction blocker. The final explanation must connect the observed issue evidence to the actual code change, not just paraphrase the diff. Write like a maintainer is going to read the patch mail cold: explain the bug in plain language, define subsystem-specific jargon the first time you need it, and make the causal story obvious. Explicitly classify evidence confidence as `reproduced`, `observed`, or `inferred`: `reproduced` means you reproduced the failure locally; `observed` means Fixer has direct crash/log/trace evidence but you did not independently reproduce it; `inferred` means the source patch is not pull-request-ready, so do not leave a source diff unless you first gather stronger observed/reproduced evidence; otherwise return a no-patch diagnosis/report. For any source-changing `observed` patch, say explicitly in `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. If you introduce non-obvious state translation, index remapping, or backend split logic, add a short source comment that explains the invariant being preserved.

Start by explaining the likely root cause from the collected perf, strace, and /proc evidence. If you cannot land a safe patch, leave a diagnosis that is strong enough for an upstream bug report.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. 

Keep the change narrowly scoped and summarize validation clearly.

In every authoring pass, your final response must start with `Subject: <single-line git commit subject>` and then include these markdown sections exactly:

## Commit Message
A short upstream-friendly explanation of what changed and why. Write it in plain language that a maintainer can follow without local complaint context. If you use subsystem jargon, define it immediately.

## Evidence Confidence
Exactly one word: `reproduced`, `observed`, or `inferred`. Use `reproduced` only when you reproduced the failure locally with a command or test, and include that command/test in `## Validation`. Use `observed` when Fixer has direct crash/log/trace evidence but you did not independently reproduce it. If `## Git Add Paths` lists source files for an `observed` patch, `## Issue Connection` must explicitly say the failure was observed by Fixer and not independently reproduced. Use `inferred` for profiler/strace/indirect evidence; inferred responses may be no-patch diagnoses or reports, but inferred source patches are not pull-request-ready until stronger evidence is gathered.

## Issue Connection
Write this as maintainer-facing patch mail, not as local Fixer notes. Cover four things explicitly in readable sentences: the user-visible symptom or the exact collected signal, the code-level cause or the cautious inference from evidence, the specific change you made, and the expected effect. Do not invent a reproducer, command line, crash, or user-visible failure that is not present in the evidence bundle. If the evidence is direct-but-not-reproduced, say it was observed by Fixer and not independently reproduced. If the evidence is indirect and you did not gather stronger evidence, do not leave a source diff; write a no-patch diagnosis/report instead. Include an explicit effect sentence such as `The expected effect is ...`, `This should reduce ...`, or `This prevents ...` for source patches. If the logic is non-obvious in code, mention that you added a short explanatory comment.

## Git Add Paths
List the repo-relative paths that belong in the final patch, one per line. Use `None` only when you intentionally made no source changes. Include intentionally new files, and do not list generated build artifacts.

## Validation
List the checks you ran, or say clearly that you could not run them. Include the independent reproduction command/test and result when `## Evidence Confidence` is `reproduced`; if reproduction was attempted but blocked, name the exact blocker and keep confidence at `observed` or `inferred`.

Before editing, read the plan at `./plan-output.txt` and follow it unless the code proves part of it wrong. If you change course, say so explicitly in the final write-up instead of silently drifting from the plan.

## Review Pass 1

You are reviewing a freshly generated fixer patch.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Review the first patch pass. The original pre-edit snapshot is available at `./source` for diffing. The workspace currently changes these repo-relative paths: engine/libcontainerd/remote/client.go. Verify that `## Git Add Paths` matches this exact set and that `## Issue Connection` explains every shipped functional file.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. The latest author response is at `./patch-output.txt`. Inspect the current code and changed paths like a strict code reviewer. Focus on correctness, regressions, maintainability, awkward control flow such as avoidable `goto`, missing validation, weak or non-gittable commit message text, and explanations that fail to connect the observed issue evidence to the code change. Also review the maintainer experience: the patch mail should be easy to accept upstream, the user-visible bug should be explained in plain language, subsystem-specific jargon should be defined when first used, and any non-obvious state translation or index remapping in code should have a short explanatory comment. Reject patches that omit `## Evidence Confidence`, use anything other than `reproduced`, `observed`, or `inferred`, or sound more certain than that evidence level allows. Reject patches that claim `reproduced` unless `## Validation` names the concrete reproduction command or test and its result. Reject patches that invent a reproducer, command line, crash, or user-visible failure not present in the evidence bundle; indirect profiler or strace evidence may justify a cautious mitigation, but the author must say it is indirect instead of presenting it as a confirmed upstream bug. Reject patches that introduce generic libc/std APIs when nearby code or project docs provide a local compat/helper API for the same job, unless the author explicitly justifies the exception. Reject validation that only reports a leaf object/syntax build when a project-level configure/build/test entrypoint exists and was not attempted; if a full build cannot run, the author must show the exact failed command and blocker.

Do not apply code changes in this pass.

Return a short markdown review report. The first non-empty line must be exactly one of:

RESULT: ok
RESULT: fix-needed

If you choose `RESULT: fix-needed`, add a `## Findings` section with concrete, actionable items.

## Refinement Pass 1

You are refining a fixer patch after an explicit code review.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Read the latest author response at `./patch-output.txt`. Read the review report at `./review-1-output.txt`. This is refinement round 1. The original pre-edit snapshot is available at `./source` if you need to compare the current patch against it. Re-read the planning pass at `./plan-output.txt` before editing. The workspace currently changes these repo-relative paths: engine/libcontainerd/remote/client.go. Either keep that exact set synchronized with `## Git Add Paths` and `## Issue Connection`, or revert any unintended file before you answer.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. Address the review findings with the smallest reasonable follow-up changes. If the review identifies a runtime or correctness bug in the changed code, you must update the code itself before answering; a metadata-only response is not sufficient. Keep the patch upstream-friendly, use local project helpers and compat APIs when available, avoid awkward control flow when a simpler structure will do, keep the final response gittable, make the maintainer-facing explanation plain and direct, keep `## Evidence Confidence` honest, add short comments for any non-obvious translation or remapping logic, run relevant project-level build/tests from the workspace root before narrower checks when possible, try a bounded independent reproduction command/test if the review or plan shows one is safe, and summarize which review findings you addressed.

In every authoring pass, your final response must start with `Subject: <single-line git commit subject>` and then include these markdown sections exactly:

## Commit Message
A short upstream-friendly explanation of what changed and why. Write it in plain language that a maintainer can follow without local complaint context. If you use subsystem jargon, define it immediately.

## Evidence Confidence
Exactly one word: `reproduced`, `observed`, or `inferred`. Use `reproduced` only when you reproduced the failure locally with a command or test, and include that command/test in `## Validation`. Use `observed` when Fixer has direct crash/log/trace evidence but you did not independently reproduce it. If `## Git Add Paths` lists source files for an `observed` patch, `## Issue Connection` must explicitly say the failure was observed by Fixer and not independently reproduced. Use `inferred` for profiler/strace/indirect evidence; inferred responses may be no-patch diagnoses or reports, but inferred source patches are not pull-request-ready until stronger evidence is gathered.

## Issue Connection
Write this as maintainer-facing patch mail, not as local Fixer notes. Cover four things explicitly in readable sentences: the user-visible symptom or the exact collected signal, the c

[truncated 4653 bytes]

Response

## Plan Pass

## Problem
Fixer observed `dockerd` with 185 threads, mostly sleeping in futexes, with strace dominated by `futex`, `nanosleep`, `epoll_pwait`, `waitid`, and a few nonblocking `recvmsg(...)=EAGAIN` calls. The bundle labels this as likely socket churn, but the backtrace is stripped and the raw artifact paths are unavailable in this workspace, so the source connection is limited.

The most relevant upstream source path is `engine/libcontainerd/remote/client.go`: `processEventStream` subscribes to containerd task events and, on stream error, waits for `IsServing` and then starts a replacement goroutine immediately. It also reads from `eventStream`/`errC` without checking channel closure. No prior Fixer patch was present beyond the `Fixer baseline` commit.

## Evidence Confidence
observed

## Proposed Subject
`libcontainerd: bound containerd event stream resubscribe churn`

## Patch Plan
Change `engine/libcontainerd/remote/client.go` so containerd event stream recovery stays in one bounded loop instead of recursively launching `go c.processEventStream(...)` on each recoverable stream error.

Handle closed `eventStream` and `errC` channels explicitly with the `ok` receive form. Treat unexpected closure like a stream failure, then wait for `waitServe(ctx)` and apply a small backoff before resubscribing. Avoid `goto`; use a helper or a clear outer `for` loop with per-subscription `context.WithCancel`.

Follow local conventions already in this subsystem: `containerd/log` via `c.logger`, `context.WithCancel` for the subscription lifetime, `time.Timer`/`time.Duration` style as used by `waitServe`, and existing error handling with `status.FromError`, `codes.Canceled`, and `context` cancellation checks.

Add focused unit coverage if a small seam can be introduced without broad refactor: simulate a stream that closes/errors repeatedly and assert the loop does not spawn replacement goroutines or spin without delay. If `containerd.Client.EventService()` is too concrete for clean faking, keep the code change minimal and validate by package build/tests plus a bounded smoke run.

## Risks
The evidence does not prove this exact source path because addresses are stripped and raw artifacts are missing. The patch should be presented as a targeted mitigation for Fixer-observed containerd event stream/socket churn, not as an independently reproduced daemon failure.

Adding backoff can delay event stream recovery slightly after containerd restarts. Keep the delay small and reset it after a successful event receive.

## Validation
From the workspace root, try the upstream test entrypoint first: `cd engine && make test-unit TESTDIRS=./libcontainerd/remote`.

Then run focused checks: `cd engine && go test ./libcontainerd/remote` and `cd engine && go test ./libcontainerd/queue ./libcontainerd/...` if dependency cost is reasonable.

Bounded independent reproduction attempt: before claiming reproduction, run a small targeted test or temporary local harness that forces repeated event stream closure/error and watches for immediate resubscribe churn or goroutine growth. If that cannot be done cleanly, final `## Issue Connection` must say the failure was observed by Fixer and not independently reproduced.

## Patch Pass

Subject: libcontainerd: bound containerd event stream reconnects

## Commit Message
Keep containerd task event stream recovery inside one goroutine and handle closed event channels explicitly. If the stream drops, dockerd now cancels the old subscription, waits for containerd to report ready, and delays briefly before resubscribing instead of spawning a replacement event processor immediately.

## Evidence Confidence
observed

## Issue Connection
Fixer observed `dockerd` with 185 threads, mostly blocked in futex waits, with strace showing repeated `futex`, `nanosleep`, `epoll_pwait`, `waitid`, and some nonblocking socket reads. This was observed by Fixer and not independently reproduced.

The cautious code-level connection is the libcontainerd task event stream, which is the daemon’s long-lived containerd event subscription for task lifecycle messages. Its recovery path spawned a new `processEventStream` goroutine on recoverable stream errors and did not distinguish closed event/error channels from real events.

This patch keeps reconnect handling in the existing goroutine, explicitly treats closed channels as a reconnect condition, preserves the existing `waitServe` readiness check, and adds a short timer before resubscribing. It follows the local `containerd/log`, `context.WithCancel`, and timer conventions already used in this subsystem. I added a short comment documenting the invariant that reconnects stay in one goroutine.

The expected effect is to reduce event-stream reconnect churn and prevent accumulation of event-processing goroutines when the containerd event subscription repeatedly fails or closes.

## Git Add Paths
engine/libcontainerd/remote/client.go

## Validation
Ran `cd engine && make test-unit TESTDIRS=./libcontainerd/remote` from the workspace root. It did not reach tests: Docker failed during the build setup with `ERROR: mkdir /root/.docker: read-only file system`.

Ran `cd engine && HOME=/tmp GOCACHE=/tmp/go-cache GOPATH=/tmp/go go test ./libcontainerd/remote`. It failed because module lookup is disabled by `-mod=readonly` and the Debian source tree does not provide the needed modules in normal module mode.

Ran `cd engine && HOME=/tmp GOCACHE=/tmp/go-cache GOPATH=/tmp/go GOFLAGS=-mod=vendor go test ./libcontainerd/remote`. It failed with inconsistent vendoring because `vendor/modules.txt` marks many modules explicit while `engine/go.mod` only declares the module.

Ran a GOPATH/vendor fallback via `/tmp/gopath`; it failed because this Debian source snapshot does not include the required containerd dependency source directories under `engine/vendor`.

Independent reproduction attempt: `pgrep -a dockerd` found no running daemon to attach a bounded `strace` to. I did not start a real daemon as a reproducer because that would alter host state. Confidence remains `observed`.

`git diff --check` passed.

## Review Pass 1

RESULT: fix-needed

## Findings

- [engine/libcontainerd/remote/client.go:741] The source comment and patch mail overstate the old behavior. The old recovery path did `go c.processEventStream(...)` and then immediately `return`, so it does not by itself “accumulate event processors”; it creates goroutine churn during repeated reconnects. Please reword the comment and `## Issue Connection` / expected effect to say the patch keeps retries in one goroutine and reduces reconnect goroutine churn, without claiming it prevents accumulation of event processors.

- The changed path set is correct: only `engine/libcontainerd/remote/client.go` is modified, and `## Git Add Paths` matches it. The validation section also attempted the documented `make test-unit TESTDIRS=./libcontainerd/remote` entrypoint and reported the exact blocker.

## Refinement Pass 1

Subject: libcontainerd: bound containerd event stream reconnects

## Commit Message
Keep containerd task event stream recovery inside one goroutine and handle closed event channels explicitly. If the stream drops, dockerd now cancels the old subscription, waits for containerd to report ready, and delays briefly before resubscribing instead of starting a replacement goroutine immediately.

Refinement round 1 addresses the review finding by rewording the source comment and patch explanation to describe reconnect goroutine churn, not accumulated event processors.

## Evidence Confidence
observed

## Issue Connection
Fixer observed `dockerd` with 185 threads, mostly blocked in futex waits, with strace showing repeated `futex`, `nanosleep`, `epoll_pwait`, `waitid`, and some nonblocking socket reads. This was observed by Fixer and not independently reproduced.

The cautious code-level connection is the libcontainerd task event stream, which is the daemon’s long-lived containerd event subscription for task lifecycle messages. Its recovery path spawned a replacement `processEventStream` goroutine on recoverable stream errors and did not distinguish closed event/error channels from real events.

This patch keeps reconnect handling in the existing goroutine, explicitly treats closed channels as a reconnect condition, preserves the existing `waitServe` readiness check, and adds a short timer before resubscribing. It follows the local `containerd/log`, `context.WithCancel`, and timer conventions already used in this subsystem. I added a short comment documenting that reconnects stay in one goroutine to avoid replacement-goroutine churn.

The expected effect is to reduce event-stream reconnect churn when the containerd event subscription repeatedly fails or closes.

## Git Add Paths
engine/libcontainerd/remote/client.go

## Validation
Ran `cd engine && make test-unit TESTDIRS=./libcontainerd/remote` from the workspace root. It did not reach tests: Docker failed during build setup with `ERROR: mkdir /root/.docker: read-only file system`.

Ran `cd engine && HOME=/tmp GOCACHE=/tmp/go-cache GOPATH=/tmp/go go test ./libcontainerd/remote`. It failed because module lookup is disabled by `-mod=readonly` and this Debian source tree does not provide the needed modules in normal module mode.

Ran `cd engine && HOME=/tmp GOCACHE=/tmp/go-cache GOPATH=/tmp/go GOFLAGS=-mod=vendor go test ./libcontainerd/remote`. It failed with inconsistent vendoring because `vendor/modules.txt` marks many modules explicit while `engine/go.mod` only declares the module.

Ran a GOPATH/vendor fallback via `/tmp/gopath`; it failed because this Debian source snapshot does not include required containerd dependency source directories under `engine/vendor`.

Independent reproduction attempt: `pgrep -a dockerd` found no running daemon to attach a bounded `strace` to. I did not start a real daemon as a reproducer because that would alter host state. Confidence remains `observed`.

`gofmt -w engine/libcontainerd/remote/client.go` and `git diff --check` passed.

## Review Pass 2

RESULT: ok

The refined patch passes review. `## Git Add Paths` matches the exact changed path set: `engine/libcontainerd/remote/client.go`.

The response keeps `## Evidence Confidence` at `observed`, explicitly says Fixer observed the failure and it was not independently reproduced, and avoids overclaiming beyond the profiler/strace evidence. The issue connection explains the shipped functional file, the event-stream recovery path being changed, and the expected effect.

Validation is acceptable for this environment: the project-level `make test-unit TESTDIRS=./libcontainerd/remote` entrypoint was attempted first and the blocker is stated, followed by narrower Go checks and `git diff --check`. The refined source comment no longer overstates accumulated processors, and I did not find a correctness or maintainability issue that should block the patch.

Diff

diff --git a/engine/libcontainerd/remote/client.go b/engine/libcontainerd/remote/client.go
index 3d3ec63..cf88ad2 100644
--- a/engine/libcontainerd/remote/client.go
+++ b/engine/libcontainerd/remote/client.go
@@ -574,6 +574,73 @@ func (c *client) processEvent(ctx context.Context, et libcontainerdtypes.EventTy
 	})
 }
 
+func (c *client) processEventEnvelope(ctx context.Context, ev *apievents.Envelope) {
+	v, err := typeurl.UnmarshalAny(ev.Event)
+	if err != nil {
+		c.logger.WithError(err).WithField("event", ev).Warn("failed to unmarshal event")
+		return
+	}
+
+	c.logger.WithField("topic", ev.Topic).Debug("event")
+
+	switch t := v.(type) {
+	case *apievents.TaskCreate:
+		c.processEvent(ctx, libcontainerdtypes.EventCreate, libcontainerdtypes.EventInfo{
+			ContainerID: t.ContainerID,
+			ProcessID:   t.ContainerID,
+			Pid:         t.Pid,
+		})
+	case *apievents.TaskStart:
+		c.processEvent(ctx, libcontainerdtypes.EventStart, libcontainerdtypes.EventInfo{
+			ContainerID: t.ContainerID,
+			ProcessID:   t.ContainerID,
+			Pid:         t.Pid,
+		})
+	case *apievents.TaskExit:
+		c.processEvent(ctx, libcontainerdtypes.EventExit, libcontainerdtypes.EventInfo{
+			ContainerID: t.ContainerID,
+			ProcessID:   t.ID,
+			Pid:         t.Pid,
+			ExitCode:    t.ExitStatus,
+			ExitedAt:    protobuf.FromTimestamp(t.ExitedAt),
+		})
+	case *apievents.TaskOOM:
+		c.processEvent(ctx, libcontainerdtypes.EventOOM, libcontainerdtypes.EventInfo{
+			ContainerID: t.ContainerID,
+		})
+	case *apievents.TaskExecAdded:
+		c.processEvent(ctx, libcontainerdtypes.EventExecAdded, libcontainerdtypes.EventInfo{
+			ContainerID: t.ContainerID,
+			ProcessID:   t.ExecID,
+		})
+	case *apievents.TaskExecStarted:
+		c.processEvent(ctx, libcontainerdtypes.EventExecStarted, libcontainerdtypes.EventInfo{
+			ContainerID: t.ContainerID,
+			ProcessID:   t.ExecID,
+			Pid:         t.Pid,
+		})
+	case *apievents.TaskPaused:
+		c.processEvent(ctx, libcontainerdtypes.EventPaused, libcontainerdtypes.EventInfo{
+			ContainerID: t.ContainerID,
+		})
+	case *apievents.TaskResumed:
+		c.processEvent(ctx, libcontainerdtypes.EventResumed, libcontainerdtypes.EventInfo{
+			ContainerID: t.ContainerID,
+		})
+	case *apievents.TaskDelete:
+		c.logger.WithFields(log.Fields{
+			"topic":     ev.Topic,
+			"type":      reflect.TypeOf(t),
+			"container": t.ContainerID,
+		}).Info("ignoring event")
+	default:
+		c.logger.WithFields(log.Fields{
+			"topic": ev.Topic,
+			"type":  reflect.TypeOf(t),
+		}).Info("ignoring event")
+	}
+}
+
 func (c *client) waitServe(ctx context.Context) bool {
 	t := 100 * time.Millisecond
 	delay := time.NewTimer(t)
@@ -607,105 +674,83 @@ func (c *client) waitServe(ctx context.Context) bool {
 }
 
 func (c *client) processEventStream(ctx context.Context, ns string) {
-	// Create a new context specifically for this subscription.
-	// The context must be cancelled to cancel the subscription.
-	// In cases where we have to restart event stream processing,
-	//   we'll need the original context b/c this one will be cancelled
-	subCtx, cancel := context.WithCancel(ctx)
-	defer cancel()
+	for {
+		if ctx.Err() != nil {
+			c.logger.WithError(ctx.Err()).Info("stopping event stream following graceful shutdown")
+			return
+		}
 
-	// Filter on both namespace *and* topic. To create an "and" filter,
-	// this must be a single, comma-separated string
-	eventStream, errC := c.client.EventService().Subscribe(subCtx, "namespace=="+ns+",topic~=|^/tasks/|")
+		// Create a new context specifically for this subscription.
+		// The context must be cancelled to cancel the subscription.
+		subCtx, cancel := context.WithCancel(ctx)
 
-	c.logger.Debug("processing event stream")
+		// Filter on both namespace *and* topic. To create an "and" filter,
+		// this must be a single, comma-separated string
+		eventStream, errC := c.client.EventService().Subscribe(subCtx, "namespace=="+ns+",topic~=|^/tasks/|")
 
-	for {
-		select {
-		case err := <-errC:
-			if err != nil {
+		c.logger.Debug("processing event stream")
+
+		restart := false
+		for !restart {
+			select {
+			case err, ok := <-errC:
+				if !ok {
+					c.logger.Warn("containerd event error channel closed")
+					restart = true
+					break
+				}
+				if err == nil {
+					c.logger.Debug("containerd event error channel returned nil error")
+					restart = true
+					break
+				}
 				errStatus, ok := status.FromError(err)
-				if !ok || errStatus.Code() != codes.Canceled {
-					c.logger.WithError(err).Error("Failed to get event")
-					c.logger.Info("Waiting for containerd to be ready to restart event processing")
-					if c.waitServe(ctx) {
-						go c.processEventStream(ctx, ns)
+				if ok && errStatus.Code() == codes.Canceled {
+					if ctx.Err() != nil {
+						c.logger.WithError(ctx.Err()).Info("stopping event stream following graceful shutdown")
+						cancel()
 						return
 					}
+					c.logger.WithError(err).Debug("containerd event stream canceled")
+					restart = true
+					break
 				}
-				c.logger.WithError(ctx.Err()).Info("stopping event stream following graceful shutdown")
-			}
-			return
-		case ev := <-eventStream:
-			if ev.Event == nil {
-				c.logger.WithField("event", ev).Warn("invalid event")
-				continue
+				c.logger.WithError(err).Error("Failed to get event")
+				restart = true
+			case ev, ok := <-eventStream:
+				if !ok {
+					c.logger.Warn("containerd event stream closed")
+					restart = true
+					break
+				}
+				if ev == nil || ev.Event == nil {
+					c.logger.WithField("event", ev).Warn("invalid event")
+					continue
+				}
+				c.processEventEnvelope(ctx, ev)
 			}
+		}
+		cancel()
 
-			v, err := typeurl.UnmarshalAny(ev.Event)
-			if err != nil {
-				c.logger.WithError(err).WithField("event", ev).Warn("failed to unmarshal event")
-				continue
-			}
+		c.logger.Info("Waiting for containerd to be ready to restart event processing")
+		if !c.waitServe(ctx) {
+			c.logger.WithError(ctx.Err()).Info("stopping event stream following graceful shutdown")
+			return
+		}
 
-			c.logger.WithField("topic", ev.Topic).Debug("event")
-
-			switch t := v.(type) {
-			case *apievents.TaskCreate:
-				c.processEvent(ctx, libcontainerdtypes.EventCreate, libcontainerdtypes.EventInfo{
-					ContainerID: t.ContainerID,
-					ProcessID:   t.ContainerID,
-					Pid:         t.Pid,
-				})
-			case *apievents.TaskStart:
-				c.processEvent(ctx, libcontainerdtypes.EventStart, libcontainerdtypes.EventInfo{
-					ContainerID: t.ContainerID,
-					ProcessID:   t.ContainerID,
-					Pid:         t.Pid,
-				})
-			case *apievents.TaskExit:
-				c.processEvent(ctx, libcontainerdtypes.EventExit, libcontainerdtypes.EventInfo{
-					ContainerID: t.ContainerID,
-					ProcessID:   t.ID,
-					Pid:         t.Pid,
-					ExitCode:    t.ExitStatus,
-					ExitedAt:    protobuf.FromTimestamp(t.ExitedAt),
-				})
-			case *apievents.TaskOOM:
-				c.processEvent(ctx, libcontainerdtypes.EventOOM, libcontainerdtypes.EventInfo{
-					ContainerID: t.ContainerID,
-				})
-			case *apievents.TaskExecAdded:
-				c.processEvent(ctx, libcontainerdtypes.EventExecAdded, libcontainerdtypes.EventInfo{
-					ContainerID: t.ContainerID,
-					ProcessID:   t.ExecID,
-				})
-			case *apievents.TaskExecStarted:
-				c.processEvent(ctx, libcontainerdtypes.EventExecStarted, libcontainerdtypes.EventInfo{
-					ContainerID: t.ContainerID,
-					ProcessID:   t.ExecID,
-					Pid:         t.Pid,
-				})
-			case *apievents.TaskPaused:
-				c.processEvent(ctx, libcontainerdtypes.EventPaused, libcontainerdtypes.EventInfo{
-					ContainerID: t.ContainerID,
-				})
-			case *apievents.TaskResumed:
-				c.processEvent(ctx, libcontainerdtypes.EventResumed, libcontainerdtypes.EventInfo{
-					ContainerID: t.ContainerID,
-				})
-			case *apievents.TaskDelete:
-				c.logger.WithFields(log.Fields{
-					"topic":     ev.Topic,
-					"type":      reflect.TypeOf(t),
-					"container": t.ContainerID,
-				}).Info("ignoring event")
-			default:
-				c.logger.WithFields(log.Fields{
-					"topic": ev.Topic,
-					"type":  reflect.TypeOf(t),
-				}).Info("ignoring event")
+		// Keep reconnects in this goroutine so a broken stream cannot churn through replacement goroutines.
+		timer := time.NewTimer(100 * time.Millisecond)
+		select {
+		case <-ctx.Done():
+			if !timer.Stop() {
+				select {
+				case <-timer.C:
+				default:
+				}
 			}
+			c.logger.WithError(ctx.Err()).Info("stopping event stream following graceful shutdown")
+			return
+		case <-timer.C:
 		}
 	}
 }

diagnosis-only report

report

dockerd likely remains stuck in a socket churn loop. A diagnosis report and patch proposal were created locally.

state: readycreated: 2026-05-13 16:57 UTCvalidation: ready
Published session

Prompt

## Plan Pass

You are planning a fixer patch before any edits happen.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. The original pre-edit snapshot is available at `./source` if you need to inspect it. For interpreter processes, plan from the script/application entrypoint evidence first and include the runtime only as a second investigation target unless the evidence proves a runtime bug.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. Inspect the relevant code, nearby callers, project contribution docs, and local helper/compat APIs, but do not edit files in this pass.

Return a short markdown plan with these exact sections:

## Problem
## Evidence Confidence
## Proposed Subject
## Patch Plan
## Risks
## Validation

Classify `## Evidence Confidence` as exactly one of `reproduced`, `observed`, or `inferred`. Use `inferred` only for a no-patch diagnosis/report plan unless you can name the extra evidence you will collect before editing; inferred source patches are blocked by Fixer because they are not pull-request-ready. For `observed` source-patch plans, plan to say in the final `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. The plan must explain how the proposed code change addresses the observed issue evidence, call out any prior Fixer patch that should be improved or replaced, reject awkward control flow such as avoidable `goto` if there is a cleaner bounded alternative, name any local helper APIs or maintainer conventions the patch should follow, and keep the intended maintainer-facing explanation clear enough that someone unfamiliar with the local complaint wording can still follow the fix. In `## Validation`, name the reproducible configure/build/test entrypoint you will try from the workspace root before any focused leaf compile or smoke check, and include one bounded independent reproduction attempt for the collected failure signal when it is safe and cheap. Do not plan to claim `reproduced` unless that reproduction command or test can actually show the failure.

## Patch Pass

You are working on a bounded fixer proposal.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Produce the smallest reasonable patch for the target repository, keep the change upstreamable, prefer the clearest control flow available, and do not keep avoidable `goto` when a simpler structure would read better. Before introducing new file, process, allocation, locking, networking, or platform APIs, inspect nearby code and project contribution docs for existing helpers or compatibility wrappers and use those local patterns unless you can explain why they do not fit. Validate from a reproducible workspace-root entrypoint before falling back to focused leaf commands; if a build or test cannot run, report the exact command, the exact blocker, and any narrower check you ran instead. During validation, also try one bounded independent reproduction of the collected failure signal when it is safe and cheap, such as a failing test, smoke command, perf/strace comparison, or before/after runtime check. Only use `reproduced` if that command or test actually reproduced the failure; otherwise keep `observed` and report the reproduction blocker. The final explanation must connect the observed issue evidence to the actual code change, not just paraphrase the diff. Write like a maintainer is going to read the patch mail cold: explain the bug in plain language, define subsystem-specific jargon the first time you need it, and make the causal story obvious. Explicitly classify evidence confidence as `reproduced`, `observed`, or `inferred`: `reproduced` means you reproduced the failure locally; `observed` means Fixer has direct crash/log/trace evidence but you did not independently reproduce it; `inferred` means the source patch is not pull-request-ready, so do not leave a source diff unless you first gather stronger observed/reproduced evidence; otherwise return a no-patch diagnosis/report. For any source-changing `observed` patch, say explicitly in `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. If you introduce non-obvious state translation, index remapping, or backend split logic, add a short source comment that explains the invariant being preserved.

Start by explaining the likely root cause from the collected perf, strace, and /proc evidence. If you cannot land a safe patch, leave a diagnosis that is strong enough for an upstream bug report.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. 

Keep the change narrowly scoped and summarize validation clearly.

In every authoring pass, your final response must start with `Subject: <single-line git commit subject>` and then include these markdown sections exactly:

## Commit Message
A short upstream-friendly explanation of what changed and why. Write it in plain language that a maintainer can follow without local complaint context. If you use subsystem jargon, define it immediately.

## Evidence Confidence
Exactly one word: `reproduced`, `observed`, or `inferred`. Use `reproduced` only when you reproduced the failure locally with a command or test, and include that command/test in `## Validation`. Use `observed` when Fixer has direct crash/log/trace evidence but you did not independently reproduce it. If `## Git Add Paths` lists source files for an `observed` patch, `## Issue Connection` must explicitly say the failure was observed by Fixer and not independently reproduced. Use `inferred` for profiler/strace/indirect evidence; inferred responses may be no-patch diagnoses or reports, but inferred source patches are not pull-request-ready until stronger evidence is gathered.

## Issue Connection
Write this as maintainer-facing patch mail, not as local Fixer notes. Cover four things explicitly in readable sentences: the user-visible symptom or the exact collected signal, the code-level cause or the cautious inference from evidence, the specific change you made, and the expected effect. Do not invent a reproducer, command line, crash, or user-visible failure that is not present in the evidence bundle. If the evidence is direct-but-not-reproduced, say it was observed by Fixer and not independently reproduced. If the evidence is indirect and you did not gather stronger evidence, do not leave a source diff; write a no-patch diagnosis/report instead. Include an explicit effect sentence such as `The expected effect is ...`, `This should reduce ...`, or `This prevents ...` for source patches. If the logic is non-obvious in code, mention that you added a short explanatory comment.

## Git Add Paths
List the repo-relative paths that belong in the final patch, one per line. Use `None` only when you intentionally made no source changes. Include intentionally new files, and do not list generated build artifacts.

## Validation
List the checks you ran, or say clearly that you could not run them. Include the independent reproduction command/test and result when `## Evidence Confidence` is `reproduced`; if reproduction was attempted but blocked, name the exact blocker and keep confidence at `observed` or `inferred`.

Before editing, read the plan at `./plan-output.txt` and follow it unless the code proves part of it wrong. If you change course, say so explicitly in the final write-up instead of silently drifting from the plan.

## Review Pass 1

You are reviewing a freshly generated fixer patch.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Review the first patch pass. The original pre-edit snapshot is available at `./source` for diffing.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. The latest author response is at `./patch-output.txt`. Inspect the current code and changed paths like a strict code reviewer. Focus on correctness, regressions, maintainability, awkward control flow such as avoidable `goto`, missing validation, weak or non-gittable commit message text, and explanations that fail to connect the observed issue evidence to the code change. Also review the maintainer experience: the patch mail should be easy to accept upstream, the user-visible bug should be explained in plain language, subsystem-specific jargon should be defined when first used, and any non-obvious state translation or index remapping in code should have a short explanatory comment. Reject patches that omit `## Evidence Confidence`, use anything other than `reproduced`, `observed`, or `inferred`, or sound more certain than that evidence level allows. Reject patches that claim `reproduced` unless `## Validation` names the concrete reproduction command or test and its result. Reject patches that invent a reproducer, command line, crash, or user-visible failure not present in the evidence bundle; indirect profiler or strace evidence may justify a cautious mitigation, but the author must say it is indirect instead of presenting it as a confirmed upstream bug. Reject patches that introduce generic libc/std APIs when nearby code or project docs provide a local compat/helper API for the same job, unless the author explicitly justifies the exception. Reject validation that only reports a leaf object/syntax build when a project-level configure/build/test entrypoint exists and was not attempted; if a full build cannot run, the author must show the exact failed command and blocker.

Do not apply code changes in this pass.

Return a short markdown review report. The first non-empty line must be exactly one of:

RESULT: ok
RESULT: fix-needed

If you choose `RESULT: fix-needed`, add a `## Findings` section with concrete, actionable items.

Response

## Plan Pass

## Problem
Fixer observed `dockerd` with many sleeping threads in futex waits, `nanosleep`, and a few `waitid(P_PIDFD, ...)` calls. The bundle labels this “socket-churn/runaway”, but the same evidence reports only `0.1%` CPU and kernel time under `__schedule`, so this is not enough to identify a Moby source bug or a precise hot loop.

## Evidence Confidence
inferred

## Proposed Subject
No source patch yet: collect symbolized `dockerd` goroutine/profile evidence before changing Moby code.

## Patch Plan
- Do not edit files in this pass. The current evidence is profiler-only/indirect and the raw artifacts referenced by `evidence.json` are not available in the workspace.
- Investigate from the `dockerd` entrypoint first: `engine/cmd/dockerd/docker.go`, daemon startup/listener setup, then `engine/libcontainerd/remote/client.go` and `engine/libcontainerd/supervisor/remote_daemon.go` because the observed `waitid(P_PIDFD, ...)` may relate to Go `os/exec` child reaping around supervised containerd or runtime processes.
- If later evidence identifies a concrete Moby loop, follow local conventions: `log.G(ctx)` for logging, `context.WithTimeout` for bounded waits, existing `pkg/process`/`pkg/pidfile` helpers for process state, and `libcontainerd/queue.Queue` event ordering rather than inventing new primitives.
- Avoid awkward control flow such as `goto`; any mitigation should be a bounded retry/timer/select structure matching nearby code.
- No prior Fixer patch for this finding was found in `debian/patches` or `.pc`; nothing should be improved or replaced yet.
- Maintainer-facing explanation should state that Fixer observed a sleeping/futex-heavy daemon sample, not an independently reproduced user-visible failure.

## Risks
- A speculative patch could mask a kernel/runtime/containerd behavior rather than fix Moby.
- The evidence conflicts with the “runaway CPU” title because sampled CPU was low.
- The unsymbolized backtrace addresses cannot be tied to a source line from the workspace alone.

## Validation
- First reproducible workspace entrypoint before any focused check: `debian/rules build` or, for full package validation, `dpkg-buildpackage -us -uc -b`.
- Upstream engine test entrypoint if a future engine patch is justified: from `engine/`, run `make test-unit` or `TESTDIRS=./libcontainerd/... TESTFLAGS='-run <focused-test>' hack/test/unit`.
- Bounded independent signal attempt: after a build, run an isolated temporary `dockerd` with `--data-root`, `--exec-root`, private unix socket, `--bridge=none`, and existing `/run/containerd/containerd.sock` for about 10-20 seconds, sample `ps`/`strace -c`/SIGUSR1 goroutine dump, then stop it. Only classify as reproduced if that command actually shows the same futex/nanosleep/waitid pattern with abnormal thread or CPU behavior.

## Patch Pass

Subject: Diagnose inconclusive dockerd futex sample

## Commit Message
No source patch was made. The collected `dockerd` evidence points to parked Go/runtime threads rather than a confirmed Moby hot loop: the process was sleeping, CPU was `0.1%`, the kernel stack was in futex wait, and the sampled hot symbol was scheduler idle time.

## Evidence Confidence
inferred

## Issue Connection
The collected signal is a `dockerd` process with 185 threads, many unfinished `futex(FUTEX_WAIT_PRIVATE, ...)` calls, some `nanosleep`, and a few `waitid(P_PIDFD, ...)` calls. `/proc` reported state `S (sleeping)`, `wchan=futex_do_wait`, and only `0.1%` CPU, so the likely root cause is not a proven busy socket churn loop but an idle or blocked Go daemon sample with child-process waiters.

I followed the saved plan and inspected the `dockerd` entrypoint plus the libcontainerd event and supervisor paths. The relevant local conventions/helpers are `log.G(ctx)` for logging, bounded `context.WithTimeout`, `pkg/pidfile`, `pkg/process`, and `libcontainerd/queue.Queue`; no relevant helper exposed a narrow correction for the observed sample. The raw investigation directory referenced by `evidence.json` is missing, and the gdb frames are unsymbolized, so there is no source line to patch safely.

The specific change made is none: leaving no source diff is intentional because this remains inferred profiler/strace evidence, and an inferred source patch would not be pull-request-ready. The expected effect is to avoid landing a speculative upstream change until stronger evidence, such as a symbolized goroutine dump or reproducible daemon trace, ties the futex/waitid pattern to a concrete Moby code path.

## Git Add Paths
None

## Validation
- `timeout 120s debian/rules build` from the workspace root failed immediately: `dh: error: unable to load addon golang: Can't locate Debian/Debhelper/Sequence/golang.pm`.
- Focused fallback `go test ./libcontainerd/queue` failed because `GOCACHE`/`HOME` were unset and module lookup was disabled.
- Focused fallback `HOME=/tmp GOCACHE=/tmp/go-build GOFLAGS=-mod=vendor go test ./libcontainerd/queue` failed because Debian’s source `go.mod` and `vendor/modules.txt` are inconsistent in this unpacked workspace.
- Independent reproduction attempt: started an isolated `/usr/sbin/dockerd` with temp `--data-root`, temp unix socket, `--storage-driver=vfs`, `--bridge=none`, and `/run/containerd/containerd.sock`, then attempted `strace -f -c`. It did not reproduce the signal: `dockerd` failed before startup with `setsockopt: operation not permitted` creating the unix socket, and `strace` attach was blocked by `ptrace(PTRACE_SEIZE): Operation not permitted`.
- Final tree check: `git status --short` and `git diff --stat` showed no changes.

## Review Pass 1

RESULT: ok

No source diff is present, and that matches the stated `inferred` confidence. The author did not leave a speculative patch for profiler/strace-only evidence, which is the correct outcome here.

The report includes the required sections, keeps `## Evidence Confidence` to an allowed single word, connects the observed futex/sleeping `dockerd` signal to the no-patch decision, names relevant local conventions/helpers, and reports a workspace-root validation attempt with the exact blocker before narrower checks. The independent reproduction attempt was also reported as blocked rather than claimed as reproduced.

diagnosis-only report

report

dockerd likely remains stuck in a socket churn loop. A diagnosis report and patch proposal were created locally.

state: readycreated: 2026-05-13 16:57 UTCvalidation: ready
Published session

Prompt

## Plan Pass

You are planning a fixer patch before any edits happen.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. The original pre-edit snapshot is available at `./source` if you need to inspect it. For interpreter processes, plan from the script/application entrypoint evidence first and include the runtime only as a second investigation target unless the evidence proves a runtime bug.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. Inspect the relevant code, nearby callers, project contribution docs, and local helper/compat APIs, but do not edit files in this pass.

Return a short markdown plan with these exact sections:

## Problem
## Evidence Confidence
## Proposed Subject
## Patch Plan
## Risks
## Validation

Classify `## Evidence Confidence` as exactly one of `reproduced`, `observed`, or `inferred`. Use `inferred` only for a no-patch diagnosis/report plan unless you can name the extra evidence you will collect before editing; inferred source patches are blocked by Fixer because they are not pull-request-ready. For `observed` source-patch plans, plan to say in the final `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. The plan must explain how the proposed code change addresses the observed issue evidence, call out any prior Fixer patch that should be improved or replaced, reject awkward control flow such as avoidable `goto` if there is a cleaner bounded alternative, name any local helper APIs or maintainer conventions the patch should follow, and keep the intended maintainer-facing explanation clear enough that someone unfamiliar with the local complaint wording can still follow the fix. In `## Validation`, name the reproducible configure/build/test entrypoint you will try from the workspace root before any focused leaf compile or smoke check, and include one bounded independent reproduction attempt for the collected failure signal when it is safe and cheap. Do not plan to claim `reproduced` unless that reproduction command or test can actually show the failure.

## Patch Pass

You are working on a bounded fixer proposal.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Produce the smallest reasonable patch for the target repository, keep the change upstreamable, prefer the clearest control flow available, and do not keep avoidable `goto` when a simpler structure would read better. Before introducing new file, process, allocation, locking, networking, or platform APIs, inspect nearby code and project contribution docs for existing helpers or compatibility wrappers and use those local patterns unless you can explain why they do not fit. Validate from a reproducible workspace-root entrypoint before falling back to focused leaf commands; if a build or test cannot run, report the exact command, the exact blocker, and any narrower check you ran instead. During validation, also try one bounded independent reproduction of the collected failure signal when it is safe and cheap, such as a failing test, smoke command, perf/strace comparison, or before/after runtime check. Only use `reproduced` if that command or test actually reproduced the failure; otherwise keep `observed` and report the reproduction blocker. The final explanation must connect the observed issue evidence to the actual code change, not just paraphrase the diff. Write like a maintainer is going to read the patch mail cold: explain the bug in plain language, define subsystem-specific jargon the first time you need it, and make the causal story obvious. Explicitly classify evidence confidence as `reproduced`, `observed`, or `inferred`: `reproduced` means you reproduced the failure locally; `observed` means Fixer has direct crash/log/trace evidence but you did not independently reproduce it; `inferred` means the source patch is not pull-request-ready, so do not leave a source diff unless you first gather stronger observed/reproduced evidence; otherwise return a no-patch diagnosis/report. For any source-changing `observed` patch, say explicitly in `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. If you introduce non-obvious state translation, index remapping, or backend split logic, add a short source comment that explains the invariant being preserved.

Start by explaining the likely root cause from the collected perf, strace, and /proc evidence. If you cannot land a safe patch, leave a diagnosis that is strong enough for an upstream bug report.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. 

Keep the change narrowly scoped and summarize validation clearly.

In every authoring pass, your final response must start with `Subject: <single-line git commit subject>` and then include these markdown sections exactly:

## Commit Message
A short upstream-friendly explanation of what changed and why. Write it in plain language that a maintainer can follow without local complaint context. If you use subsystem jargon, define it immediately.

## Evidence Confidence
Exactly one word: `reproduced`, `observed`, or `inferred`. Use `reproduced` only when you reproduced the failure locally with a command or test, and include that command/test in `## Validation`. Use `observed` when Fixer has direct crash/log/trace evidence but you did not independently reproduce it. If `## Git Add Paths` lists source files for an `observed` patch, `## Issue Connection` must explicitly say the failure was observed by Fixer and not independently reproduced. Use `inferred` for profiler/strace/indirect evidence; inferred responses may be no-patch diagnoses or reports, but inferred source patches are not pull-request-ready until stronger evidence is gathered.

## Issue Connection
Write this as maintainer-facing patch mail, not as local Fixer notes. Cover four things explicitly in readable sentences: the user-visible symptom or the exact collected signal, the code-level cause or the cautious inference from evidence, the specific change you made, and the expected effect. Do not invent a reproducer, command line, crash, or user-visible failure that is not present in the evidence bundle. If the evidence is direct-but-not-reproduced, say it was observed by Fixer and not independently reproduced. If the evidence is indirect and you did not gather stronger evidence, do not leave a source diff; write a no-patch diagnosis/report instead. Include an explicit effect sentence such as `The expected effect is ...`, `This should reduce ...`, or `This prevents ...` for source patches. If the logic is non-obvious in code, mention that you added a short explanatory comment.

## Git Add Paths
List the repo-relative paths that belong in the final patch, one per line. Use `None` only when you intentionally made no source changes. Include intentionally new files, and do not list generated build artifacts.

## Validation
List the checks you ran, or say clearly that you could not run them. Include the independent reproduction command/test and result when `## Evidence Confidence` is `reproduced`; if reproduction was attempted but blocked, name the exact blocker and keep confidence at `observed` or `inferred`.

Before editing, read the plan at `./plan-output.txt` and follow it unless the code proves part of it wrong. If you change course, say so explicitly in the final write-up instead of silently drifting from the plan.

## Review Pass 1

You are reviewing a freshly generated fixer patch.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Review the first patch pass. The original pre-edit snapshot is available at `./source` for diffing.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. The latest author response is at `./patch-output.txt`. Inspect the current code and changed paths like a strict code reviewer. Focus on correctness, regressions, maintainability, awkward control flow such as avoidable `goto`, missing validation, weak or non-gittable commit message text, and explanations that fail to connect the observed issue evidence to the code change. Also review the maintainer experience: the patch mail should be easy to accept upstream, the user-visible bug should be explained in plain language, subsystem-specific jargon should be defined when first used, and any non-obvious state translation or index remapping in code should have a short explanatory comment. Reject patches that omit `## Evidence Confidence`, use anything other than `reproduced`, `observed`, or `inferred`, or sound more certain than that evidence level allows. Reject patches that claim `reproduced` unless `## Validation` names the concrete reproduction command or test and its result. Reject patches that invent a reproducer, command line, crash, or user-visible failure not present in the evidence bundle; indirect profiler or strace evidence may justify a cautious mitigation, but the author must say it is indirect instead of presenting it as a confirmed upstream bug. Reject patches that introduce generic libc/std APIs when nearby code or project docs provide a local compat/helper API for the same job, unless the author explicitly justifies the exception. Reject validation that only reports a leaf object/syntax build when a project-level configure/build/test entrypoint exists and was not attempted; if a full build cannot run, the author must show the exact failed command and blocker.

Do not apply code changes in this pass.

Return a short markdown review report. The first non-empty line must be exactly one of:

RESULT: ok
RESULT: fix-needed

If you choose `RESULT: fix-needed`, add a `## Findings` section with concrete, actionable items.

Response

## Plan Pass

## Problem
Fixer observed `dockerd` with many sleeping threads in futex waits, `nanosleep`, and a few `waitid(P_PIDFD, ...)` calls. The bundle labels this “socket-churn/runaway”, but the same evidence reports only `0.1%` CPU and kernel time under `__schedule`, so this is not enough to identify a Moby source bug or a precise hot loop.

## Evidence Confidence
inferred

## Proposed Subject
No source patch yet: collect symbolized `dockerd` goroutine/profile evidence before changing Moby code.

## Patch Plan
- Do not edit files in this pass. The current evidence is profiler-only/indirect and the raw artifacts referenced by `evidence.json` are not available in the workspace.
- Investigate from the `dockerd` entrypoint first: `engine/cmd/dockerd/docker.go`, daemon startup/listener setup, then `engine/libcontainerd/remote/client.go` and `engine/libcontainerd/supervisor/remote_daemon.go` because the observed `waitid(P_PIDFD, ...)` may relate to Go `os/exec` child reaping around supervised containerd or runtime processes.
- If later evidence identifies a concrete Moby loop, follow local conventions: `log.G(ctx)` for logging, `context.WithTimeout` for bounded waits, existing `pkg/process`/`pkg/pidfile` helpers for process state, and `libcontainerd/queue.Queue` event ordering rather than inventing new primitives.
- Avoid awkward control flow such as `goto`; any mitigation should be a bounded retry/timer/select structure matching nearby code.
- No prior Fixer patch for this finding was found in `debian/patches` or `.pc`; nothing should be improved or replaced yet.
- Maintainer-facing explanation should state that Fixer observed a sleeping/futex-heavy daemon sample, not an independently reproduced user-visible failure.

## Risks
- A speculative patch could mask a kernel/runtime/containerd behavior rather than fix Moby.
- The evidence conflicts with the “runaway CPU” title because sampled CPU was low.
- The unsymbolized backtrace addresses cannot be tied to a source line from the workspace alone.

## Validation
- First reproducible workspace entrypoint before any focused check: `debian/rules build` or, for full package validation, `dpkg-buildpackage -us -uc -b`.
- Upstream engine test entrypoint if a future engine patch is justified: from `engine/`, run `make test-unit` or `TESTDIRS=./libcontainerd/... TESTFLAGS='-run <focused-test>' hack/test/unit`.
- Bounded independent signal attempt: after a build, run an isolated temporary `dockerd` with `--data-root`, `--exec-root`, private unix socket, `--bridge=none`, and existing `/run/containerd/containerd.sock` for about 10-20 seconds, sample `ps`/`strace -c`/SIGUSR1 goroutine dump, then stop it. Only classify as reproduced if that command actually shows the same futex/nanosleep/waitid pattern with abnormal thread or CPU behavior.

## Patch Pass

Subject: Diagnose inconclusive dockerd futex sample

## Commit Message
No source patch was made. The collected `dockerd` evidence points to parked Go/runtime threads rather than a confirmed Moby hot loop: the process was sleeping, CPU was `0.1%`, the kernel stack was in futex wait, and the sampled hot symbol was scheduler idle time.

## Evidence Confidence
inferred

## Issue Connection
The collected signal is a `dockerd` process with 185 threads, many unfinished `futex(FUTEX_WAIT_PRIVATE, ...)` calls, some `nanosleep`, and a few `waitid(P_PIDFD, ...)` calls. `/proc` reported state `S (sleeping)`, `wchan=futex_do_wait`, and only `0.1%` CPU, so the likely root cause is not a proven busy socket churn loop but an idle or blocked Go daemon sample with child-process waiters.

I followed the saved plan and inspected the `dockerd` entrypoint plus the libcontainerd event and supervisor paths. The relevant local conventions/helpers are `log.G(ctx)` for logging, bounded `context.WithTimeout`, `pkg/pidfile`, `pkg/process`, and `libcontainerd/queue.Queue`; no relevant helper exposed a narrow correction for the observed sample. The raw investigation directory referenced by `evidence.json` is missing, and the gdb frames are unsymbolized, so there is no source line to patch safely.

The specific change made is none: leaving no source diff is intentional because this remains inferred profiler/strace evidence, and an inferred source patch would not be pull-request-ready. The expected effect is to avoid landing a speculative upstream change until stronger evidence, such as a symbolized goroutine dump or reproducible daemon trace, ties the futex/waitid pattern to a concrete Moby code path.

## Git Add Paths
None

## Validation
- `timeout 120s debian/rules build` from the workspace root failed immediately: `dh: error: unable to load addon golang: Can't locate Debian/Debhelper/Sequence/golang.pm`.
- Focused fallback `go test ./libcontainerd/queue` failed because `GOCACHE`/`HOME` were unset and module lookup was disabled.
- Focused fallback `HOME=/tmp GOCACHE=/tmp/go-build GOFLAGS=-mod=vendor go test ./libcontainerd/queue` failed because Debian’s source `go.mod` and `vendor/modules.txt` are inconsistent in this unpacked workspace.
- Independent reproduction attempt: started an isolated `/usr/sbin/dockerd` with temp `--data-root`, temp unix socket, `--storage-driver=vfs`, `--bridge=none`, and `/run/containerd/containerd.sock`, then attempted `strace -f -c`. It did not reproduce the signal: `dockerd` failed before startup with `setsockopt: operation not permitted` creating the unix socket, and `strace` attach was blocked by `ptrace(PTRACE_SEIZE): Operation not permitted`.
- Final tree check: `git status --short` and `git diff --stat` showed no changes.

## Review Pass 1

RESULT: ok

No source diff is present, and that matches the stated `inferred` confidence. The author did not leave a speculative patch for profiler/strace-only evidence, which is the correct outcome here.

The report includes the required sections, keeps `## Evidence Confidence` to an allowed single word, connects the observed futex/sleeping `dockerd` signal to the no-patch decision, names relevant local conventions/helpers, and reports a workspace-root validation attempt with the exact blocker before narrower checks. The independent reproduction attempt was also reported as blocked rather than claimed as reproduced.

diagnosis-only report

report

dockerd likely remains stuck in a socket churn loop. A diagnosis report and patch proposal were created locally.

state: readycreated: 2026-05-13 15:14 UTCvalidation: ready
Published session

Prompt

## Plan Pass

You are planning a fixer patch before any edits happen.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. The original pre-edit snapshot is available at `./source` if you need to inspect it. For interpreter processes, plan from the script/application entrypoint evidence first and include the runtime only as a second investigation target unless the evidence proves a runtime bug.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. Inspect the relevant code, nearby callers, project contribution docs, and local helper/compat APIs, but do not edit files in this pass.

Return a short markdown plan with these exact sections:

## Problem
## Evidence Confidence
## Proposed Subject
## Patch Plan
## Risks
## Validation

Classify `## Evidence Confidence` as exactly one of `reproduced`, `observed`, or `inferred`. Use `inferred` only for a no-patch diagnosis/report plan unless you can name the extra evidence you will collect before editing; inferred source patches are blocked by Fixer because they are not pull-request-ready. For `observed` source-patch plans, plan to say in the final `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. The plan must explain how the proposed code change addresses the observed issue evidence, call out any prior Fixer patch that should be improved or replaced, reject awkward control flow such as avoidable `goto` if there is a cleaner bounded alternative, name any local helper APIs or maintainer conventions the patch should follow, and keep the intended maintainer-facing explanation clear enough that someone unfamiliar with the local complaint wording can still follow the fix. In `## Validation`, name the reproducible configure/build/test entrypoint you will try from the workspace root before any focused leaf compile or smoke check, and include one bounded independent reproduction attempt for the collected failure signal when it is safe and cheap. Do not plan to claim `reproduced` unless that reproduction command or test can actually show the failure.

## Patch Pass

You are working on a bounded fixer proposal.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Produce the smallest reasonable patch for the target repository, keep the change upstreamable, prefer the clearest control flow available, and do not keep avoidable `goto` when a simpler structure would read better. Before introducing new file, process, allocation, locking, networking, or platform APIs, inspect nearby code and project contribution docs for existing helpers or compatibility wrappers and use those local patterns unless you can explain why they do not fit. Validate from a reproducible workspace-root entrypoint before falling back to focused leaf commands; if a build or test cannot run, report the exact command, the exact blocker, and any narrower check you ran instead. During validation, also try one bounded independent reproduction of the collected failure signal when it is safe and cheap, such as a failing test, smoke command, perf/strace comparison, or before/after runtime check. Only use `reproduced` if that command or test actually reproduced the failure; otherwise keep `observed` and report the reproduction blocker. The final explanation must connect the observed issue evidence to the actual code change, not just paraphrase the diff. Write like a maintainer is going to read the patch mail cold: explain the bug in plain language, define subsystem-specific jargon the first time you need it, and make the causal story obvious. Explicitly classify evidence confidence as `reproduced`, `observed`, or `inferred`: `reproduced` means you reproduced the failure locally; `observed` means Fixer has direct crash/log/trace evidence but you did not independently reproduce it; `inferred` means the source patch is not pull-request-ready, so do not leave a source diff unless you first gather stronger observed/reproduced evidence; otherwise return a no-patch diagnosis/report. For any source-changing `observed` patch, say explicitly in `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. If you introduce non-obvious state translation, index remapping, or backend split logic, add a short source comment that explains the invariant being preserved.

Start by explaining the likely root cause from the collected perf, strace, and /proc evidence. If you cannot land a safe patch, leave a diagnosis that is strong enough for an upstream bug report.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. 

Keep the change narrowly scoped and summarize validation clearly.

In every authoring pass, your final response must start with `Subject: <single-line git commit subject>` and then include these markdown sections exactly:

## Commit Message
A short upstream-friendly explanation of what changed and why. Write it in plain language that a maintainer can follow without local complaint context. If you use subsystem jargon, define it immediately.

## Evidence Confidence
Exactly one word: `reproduced`, `observed`, or `inferred`. Use `reproduced` only when you reproduced the failure locally with a command or test, and include that command/test in `## Validation`. Use `observed` when Fixer has direct crash/log/trace evidence but you did not independently reproduce it. If `## Git Add Paths` lists source files for an `observed` patch, `## Issue Connection` must explicitly say the failure was observed by Fixer and not independently reproduced. Use `inferred` for profiler/strace/indirect evidence; inferred responses may be no-patch diagnoses or reports, but inferred source patches are not pull-request-ready until stronger evidence is gathered.

## Issue Connection
Write this as maintainer-facing patch mail, not as local Fixer notes. Cover four things explicitly in readable sentences: the user-visible symptom or the exact collected signal, the code-level cause or the cautious inference from evidence, the specific change you made, and the expected effect. Do not invent a reproducer, command line, crash, or user-visible failure that is not present in the evidence bundle. If the evidence is direct-but-not-reproduced, say it was observed by Fixer and not independently reproduced. If the evidence is indirect and you did not gather stronger evidence, do not leave a source diff; write a no-patch diagnosis/report instead. Include an explicit effect sentence such as `The expected effect is ...`, `This should reduce ...`, or `This prevents ...` for source patches. If the logic is non-obvious in code, mention that you added a short explanatory comment.

## Git Add Paths
List the repo-relative paths that belong in the final patch, one per line. Use `None` only when you intentionally made no source changes. Include intentionally new files, and do not list generated build artifacts.

## Validation
List the checks you ran, or say clearly that you could not run them. Include the independent reproduction command/test and result when `## Evidence Confidence` is `reproduced`; if reproduction was attempted but blocked, name the exact blocker and keep confidence at `observed` or `inferred`.

Before editing, read the plan at `./plan-output.txt` and follow it unless the code proves part of it wrong. If you change course, say so explicitly in the final write-up instead of silently drifting from the plan.

## Review Pass 1

You are reviewing a freshly generated fixer patch.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Review the first patch pass. The original pre-edit snapshot is available at `./source` for diffing.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. The latest author response is at `./patch-output.txt`. Inspect the current code and changed paths like a strict code reviewer. Focus on correctness, regressions, maintainability, awkward control flow such as avoidable `goto`, missing validation, weak or non-gittable commit message text, and explanations that fail to connect the observed issue evidence to the code change. Also review the maintainer experience: the patch mail should be easy to accept upstream, the user-visible bug should be explained in plain language, subsystem-specific jargon should be defined when first used, and any non-obvious state translation or index remapping in code should have a short explanatory comment. Reject patches that omit `## Evidence Confidence`, use anything other than `reproduced`, `observed`, or `inferred`, or sound more certain than that evidence level allows. Reject patches that claim `reproduced` unless `## Validation` names the concrete reproduction command or test and its result. Reject patches that invent a reproducer, command line, crash, or user-visible failure not present in the evidence bundle; indirect profiler or strace evidence may justify a cautious mitigation, but the author must say it is indirect instead of presenting it as a confirmed upstream bug. Reject patches that introduce generic libc/std APIs when nearby code or project docs provide a local compat/helper API for the same job, unless the author explicitly justifies the exception. Reject validation that only reports a leaf object/syntax build when a project-level configure/build/test entrypoint exists and was not attempted; if a full build cannot run, the author must show the exact failed command and blocker.

Do not apply code changes in this pass.

Return a short markdown review report. The first non-empty line must be exactly one of:

RESULT: ok
RESULT: fix-needed

If you choose `RESULT: fix-needed`, add a `## Findings` section with concrete, actionable items.

Response

## Plan Pass

## Problem
Fixer observed `dockerd` with a profiler/strace signal labeled `socket-churn`, but the included excerpts show a sleeping process, 0.1% CPU, many goroutines blocked in `futex`, and a couple of `waitid(P_PIDFD, ...)` calls. That matches an idle Go daemon and its containerd supervisor wait path more than a confirmed busy retry loop.

## Evidence Confidence
inferred

## Proposed Subject
No source patch yet: diagnose `dockerd` idle supervisor/profile signal as insufficient for an upstream-ready bug fix.

## Patch Plan
Do not edit files in this pass. The evidence bundle has profiler-only/indirect data, unsymbolized Go backtraces, missing raw artifact files under `/var/lib/fixer/investigations/...`, and no reproduced user-visible failure.

Relevant code inspected: `engine/cmd/dockerd/docker.go` entrypoint and `engine/libcontainerd/supervisor/remote_daemon.go`. The nearby subsystem already uses local conventions/helpers: `pkg/pidfile`, `pkg/process`, containerd `log.G`, `containerd.New` dial options, and the existing `runtime.LockOSThread` pattern around `SysProcAttr.Pdeathsig`. No awkward `goto` or obvious bounded control-flow cleanup is justified by the current evidence.

No prior Fixer patch was present in the workspace; only Debian’s existing quilt patches are applied.

## Risks
Patching from this evidence would likely create a speculative change against normal daemon behavior. In particular, changing the containerd supervisor wait/restart logic could regress shutdown, child reaping, or restart behavior without proving it addresses the observed profile.

## Validation
Before any future focused check, try the workspace-root Debian entrypoint: `DEB_BUILD_OPTIONS=nocheck dpkg-buildpackage -us -uc -b`, or the full `debian/rules build`/`debian/rules binary` path if dependencies are available.

For a bounded independent reproduction attempt, run a local `dockerd --version` smoke check after build and, only if a daemon can safely be started in the test environment, sample an idle `dockerd` briefly with `strace -f -p <pid>` to see whether the same `futex`/`waitid(P_PIDFD, ...)` pattern appears without a functional failure. A future source patch should require symbolized goroutine stacks or a cheap reproducer that shows real socket churn, CPU burn, leaked threads, or failed containerd supervision.

## Patch Pass

Subject: No patch: diagnose idle dockerd profile signal

## Commit Message
No source change is proposed. The collected signal looks like an idle `dockerd` sample rather than an upstream-ready daemon bug: the daemon was sleeping, using 0.1% CPU, and blocked mostly in Go futex waits and scheduler paths.

## Evidence Confidence
inferred

## Issue Connection
The likely root cause of the collected perf, strace, and `/proc` evidence is a profiler classifier false positive over an idle Go daemon. Fixer labeled the sample as `socket-churn`, but the evidence shows `dockerd` in `S (sleeping)`, perf hot in `__schedule`, `futex` waits in the kernel stack, mostly voluntary context switches, and only 0.1% CPU. The strace excerpt does not show rapid socket retry activity; it shows many blocked futex waits and a couple of `waitid(P_PIDFD, ...)` calls, which are consistent with normal Go runtime and child-process wait behavior.

I inspected the daemon entrypoint and the containerd supervisor path. The relevant local helpers and conventions are already in use: `pkg/pidfile`, `pkg/process`, containerd `log.G`, `containerd.New` dial options, and the existing `runtime.LockOSThread` convention around `SysProcAttr.Pdeathsig`. I also read `engine/CONTRIBUTING.md` and `engine/TESTING.md`; they expect clear bug evidence and tests for fixes. The raw artifact directory referenced by the evidence bundle was not available, so I could not obtain symbolized stacks or a complete strace.

I followed the saved plan and did not change course. No source diff was left because this remains indirect evidence, and an inferred source patch would not be pull-request-ready. The expected effect of this no-patch report is to avoid a speculative change to daemon/containerd supervision code until stronger evidence shows actual socket churn, CPU burn, leaked threads, or failed supervision.

## Git Add Paths
None

## Validation
`DEB_BUILD_OPTIONS=nocheck dpkg-buildpackage -us -uc -b` from the workspace root failed before build because Debian build dependencies are not installed. The blocker was `dpkg-checkbuilddeps: error: unmet build dependencies`, beginning with `dh-golang`, `golang-any`, `go-md2man`, and many Go library packages.

For a bounded reproduction attempt, I checked for a local daemon target with `pgrep -a dockerd || true; command -v strace || true; command -v perf || true; test -e /usr/sbin/dockerd; echo "usr_sbin_dockerd_exists=$?"`. `strace` and `perf` are present, but there is no running `dockerd` and `/usr/sbin/dockerd` is absent, so I could not safely reproduce or compare the collected runtime signal locally.

## Review Pass 1

RESULT: ok

diagnosis-only report

report

dockerd likely remains stuck in a socket churn loop. A diagnosis report and patch proposal were created locally.

state: readycreated: 2026-05-13 15:14 UTCvalidation: ready
Published session

Prompt

## Plan Pass

You are planning a fixer patch before any edits happen.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. The original pre-edit snapshot is available at `./source` if you need to inspect it. For interpreter processes, plan from the script/application entrypoint evidence first and include the runtime only as a second investigation target unless the evidence proves a runtime bug.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. Inspect the relevant code, nearby callers, project contribution docs, and local helper/compat APIs, but do not edit files in this pass.

Return a short markdown plan with these exact sections:

## Problem
## Evidence Confidence
## Proposed Subject
## Patch Plan
## Risks
## Validation

Classify `## Evidence Confidence` as exactly one of `reproduced`, `observed`, or `inferred`. Use `inferred` only for a no-patch diagnosis/report plan unless you can name the extra evidence you will collect before editing; inferred source patches are blocked by Fixer because they are not pull-request-ready. For `observed` source-patch plans, plan to say in the final `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. The plan must explain how the proposed code change addresses the observed issue evidence, call out any prior Fixer patch that should be improved or replaced, reject awkward control flow such as avoidable `goto` if there is a cleaner bounded alternative, name any local helper APIs or maintainer conventions the patch should follow, and keep the intended maintainer-facing explanation clear enough that someone unfamiliar with the local complaint wording can still follow the fix. In `## Validation`, name the reproducible configure/build/test entrypoint you will try from the workspace root before any focused leaf compile or smoke check, and include one bounded independent reproduction attempt for the collected failure signal when it is safe and cheap. Do not plan to claim `reproduced` unless that reproduction command or test can actually show the failure.

## Patch Pass

You are working on a bounded fixer proposal.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Produce the smallest reasonable patch for the target repository, keep the change upstreamable, prefer the clearest control flow available, and do not keep avoidable `goto` when a simpler structure would read better. Before introducing new file, process, allocation, locking, networking, or platform APIs, inspect nearby code and project contribution docs for existing helpers or compatibility wrappers and use those local patterns unless you can explain why they do not fit. Validate from a reproducible workspace-root entrypoint before falling back to focused leaf commands; if a build or test cannot run, report the exact command, the exact blocker, and any narrower check you ran instead. During validation, also try one bounded independent reproduction of the collected failure signal when it is safe and cheap, such as a failing test, smoke command, perf/strace comparison, or before/after runtime check. Only use `reproduced` if that command or test actually reproduced the failure; otherwise keep `observed` and report the reproduction blocker. The final explanation must connect the observed issue evidence to the actual code change, not just paraphrase the diff. Write like a maintainer is going to read the patch mail cold: explain the bug in plain language, define subsystem-specific jargon the first time you need it, and make the causal story obvious. Explicitly classify evidence confidence as `reproduced`, `observed`, or `inferred`: `reproduced` means you reproduced the failure locally; `observed` means Fixer has direct crash/log/trace evidence but you did not independently reproduce it; `inferred` means the source patch is not pull-request-ready, so do not leave a source diff unless you first gather stronger observed/reproduced evidence; otherwise return a no-patch diagnosis/report. For any source-changing `observed` patch, say explicitly in `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. If you introduce non-obvious state translation, index remapping, or backend split logic, add a short source comment that explains the invariant being preserved.

Start by explaining the likely root cause from the collected perf, strace, and /proc evidence. If you cannot land a safe patch, leave a diagnosis that is strong enough for an upstream bug report.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. 

Keep the change narrowly scoped and summarize validation clearly.

In every authoring pass, your final response must start with `Subject: <single-line git commit subject>` and then include these markdown sections exactly:

## Commit Message
A short upstream-friendly explanation of what changed and why. Write it in plain language that a maintainer can follow without local complaint context. If you use subsystem jargon, define it immediately.

## Evidence Confidence
Exactly one word: `reproduced`, `observed`, or `inferred`. Use `reproduced` only when you reproduced the failure locally with a command or test, and include that command/test in `## Validation`. Use `observed` when Fixer has direct crash/log/trace evidence but you did not independently reproduce it. If `## Git Add Paths` lists source files for an `observed` patch, `## Issue Connection` must explicitly say the failure was observed by Fixer and not independently reproduced. Use `inferred` for profiler/strace/indirect evidence; inferred responses may be no-patch diagnoses or reports, but inferred source patches are not pull-request-ready until stronger evidence is gathered.

## Issue Connection
Write this as maintainer-facing patch mail, not as local Fixer notes. Cover four things explicitly in readable sentences: the user-visible symptom or the exact collected signal, the code-level cause or the cautious inference from evidence, the specific change you made, and the expected effect. Do not invent a reproducer, command line, crash, or user-visible failure that is not present in the evidence bundle. If the evidence is direct-but-not-reproduced, say it was observed by Fixer and not independently reproduced. If the evidence is indirect and you did not gather stronger evidence, do not leave a source diff; write a no-patch diagnosis/report instead. Include an explicit effect sentence such as `The expected effect is ...`, `This should reduce ...`, or `This prevents ...` for source patches. If the logic is non-obvious in code, mention that you added a short explanatory comment.

## Git Add Paths
List the repo-relative paths that belong in the final patch, one per line. Use `None` only when you intentionally made no source changes. Include intentionally new files, and do not list generated build artifacts.

## Validation
List the checks you ran, or say clearly that you could not run them. Include the independent reproduction command/test and result when `## Evidence Confidence` is `reproduced`; if reproduction was attempted but blocked, name the exact blocker and keep confidence at `observed` or `inferred`.

Before editing, read the plan at `./plan-output.txt` and follow it unless the code proves part of it wrong. If you change course, say so explicitly in the final write-up instead of silently drifting from the plan.

## Review Pass 1

You are reviewing a freshly generated fixer patch.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Review the first patch pass. The original pre-edit snapshot is available at `./source` for diffing.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. The latest author response is at `./patch-output.txt`. Inspect the current code and changed paths like a strict code reviewer. Focus on correctness, regressions, maintainability, awkward control flow such as avoidable `goto`, missing validation, weak or non-gittable commit message text, and explanations that fail to connect the observed issue evidence to the code change. Also review the maintainer experience: the patch mail should be easy to accept upstream, the user-visible bug should be explained in plain language, subsystem-specific jargon should be defined when first used, and any non-obvious state translation or index remapping in code should have a short explanatory comment. Reject patches that omit `## Evidence Confidence`, use anything other than `reproduced`, `observed`, or `inferred`, or sound more certain than that evidence level allows. Reject patches that claim `reproduced` unless `## Validation` names the concrete reproduction command or test and its result. Reject patches that invent a reproducer, command line, crash, or user-visible failure not present in the evidence bundle; indirect profiler or strace evidence may justify a cautious mitigation, but the author must say it is indirect instead of presenting it as a confirmed upstream bug. Reject patches that introduce generic libc/std APIs when nearby code or project docs provide a local compat/helper API for the same job, unless the author explicitly justifies the exception. Reject validation that only reports a leaf object/syntax build when a project-level configure/build/test entrypoint exists and was not attempted; if a full build cannot run, the author must show the exact failed command and blocker.

Do not apply code changes in this pass.

Return a short markdown review report. The first non-empty line must be exactly one of:

RESULT: ok
RESULT: fix-needed

If you choose `RESULT: fix-needed`, add a `## Findings` section with concrete, actionable items.

Response

## Plan Pass

## Problem
Fixer observed `dockerd` with a profiler/strace signal labeled `socket-churn`, but the included excerpts show a sleeping process, 0.1% CPU, many goroutines blocked in `futex`, and a couple of `waitid(P_PIDFD, ...)` calls. That matches an idle Go daemon and its containerd supervisor wait path more than a confirmed busy retry loop.

## Evidence Confidence
inferred

## Proposed Subject
No source patch yet: diagnose `dockerd` idle supervisor/profile signal as insufficient for an upstream-ready bug fix.

## Patch Plan
Do not edit files in this pass. The evidence bundle has profiler-only/indirect data, unsymbolized Go backtraces, missing raw artifact files under `/var/lib/fixer/investigations/...`, and no reproduced user-visible failure.

Relevant code inspected: `engine/cmd/dockerd/docker.go` entrypoint and `engine/libcontainerd/supervisor/remote_daemon.go`. The nearby subsystem already uses local conventions/helpers: `pkg/pidfile`, `pkg/process`, containerd `log.G`, `containerd.New` dial options, and the existing `runtime.LockOSThread` pattern around `SysProcAttr.Pdeathsig`. No awkward `goto` or obvious bounded control-flow cleanup is justified by the current evidence.

No prior Fixer patch was present in the workspace; only Debian’s existing quilt patches are applied.

## Risks
Patching from this evidence would likely create a speculative change against normal daemon behavior. In particular, changing the containerd supervisor wait/restart logic could regress shutdown, child reaping, or restart behavior without proving it addresses the observed profile.

## Validation
Before any future focused check, try the workspace-root Debian entrypoint: `DEB_BUILD_OPTIONS=nocheck dpkg-buildpackage -us -uc -b`, or the full `debian/rules build`/`debian/rules binary` path if dependencies are available.

For a bounded independent reproduction attempt, run a local `dockerd --version` smoke check after build and, only if a daemon can safely be started in the test environment, sample an idle `dockerd` briefly with `strace -f -p <pid>` to see whether the same `futex`/`waitid(P_PIDFD, ...)` pattern appears without a functional failure. A future source patch should require symbolized goroutine stacks or a cheap reproducer that shows real socket churn, CPU burn, leaked threads, or failed containerd supervision.

## Patch Pass

Subject: No patch: diagnose idle dockerd profile signal

## Commit Message
No source change is proposed. The collected signal looks like an idle `dockerd` sample rather than an upstream-ready daemon bug: the daemon was sleeping, using 0.1% CPU, and blocked mostly in Go futex waits and scheduler paths.

## Evidence Confidence
inferred

## Issue Connection
The likely root cause of the collected perf, strace, and `/proc` evidence is a profiler classifier false positive over an idle Go daemon. Fixer labeled the sample as `socket-churn`, but the evidence shows `dockerd` in `S (sleeping)`, perf hot in `__schedule`, `futex` waits in the kernel stack, mostly voluntary context switches, and only 0.1% CPU. The strace excerpt does not show rapid socket retry activity; it shows many blocked futex waits and a couple of `waitid(P_PIDFD, ...)` calls, which are consistent with normal Go runtime and child-process wait behavior.

I inspected the daemon entrypoint and the containerd supervisor path. The relevant local helpers and conventions are already in use: `pkg/pidfile`, `pkg/process`, containerd `log.G`, `containerd.New` dial options, and the existing `runtime.LockOSThread` convention around `SysProcAttr.Pdeathsig`. I also read `engine/CONTRIBUTING.md` and `engine/TESTING.md`; they expect clear bug evidence and tests for fixes. The raw artifact directory referenced by the evidence bundle was not available, so I could not obtain symbolized stacks or a complete strace.

I followed the saved plan and did not change course. No source diff was left because this remains indirect evidence, and an inferred source patch would not be pull-request-ready. The expected effect of this no-patch report is to avoid a speculative change to daemon/containerd supervision code until stronger evidence shows actual socket churn, CPU burn, leaked threads, or failed supervision.

## Git Add Paths
None

## Validation
`DEB_BUILD_OPTIONS=nocheck dpkg-buildpackage -us -uc -b` from the workspace root failed before build because Debian build dependencies are not installed. The blocker was `dpkg-checkbuilddeps: error: unmet build dependencies`, beginning with `dh-golang`, `golang-any`, `go-md2man`, and many Go library packages.

For a bounded reproduction attempt, I checked for a local daemon target with `pgrep -a dockerd || true; command -v strace || true; command -v perf || true; test -e /usr/sbin/dockerd; echo "usr_sbin_dockerd_exists=$?"`. `strace` and `perf` are present, but there is no running `dockerd` and `/usr/sbin/dockerd` is absent, so I could not safely reproduce or compare the collected runtime signal locally.

## Review Pass 1

RESULT: ok

diagnosis-only report

report

dockerd likely remains stuck in a socket churn loop. A diagnosis report and patch proposal were created locally.

state: readycreated: 2026-05-13 14:11 UTCvalidation: ready
Published session

Prompt

## Plan Pass

You are planning a fixer patch before any edits happen.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. The original pre-edit snapshot is available at `./source` if you need to inspect it. For interpreter processes, plan from the script/application entrypoint evidence first and include the runtime only as a second investigation target unless the evidence proves a runtime bug.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. Inspect the relevant code, nearby callers, project contribution docs, and local helper/compat APIs, but do not edit files in this pass.

Return a short markdown plan with these exact sections:

## Problem
## Evidence Confidence
## Proposed Subject
## Patch Plan
## Risks
## Validation

Classify `## Evidence Confidence` as exactly one of `reproduced`, `observed`, or `inferred`. Use `inferred` only for a no-patch diagnosis/report plan unless you can name the extra evidence you will collect before editing; inferred source patches are blocked by Fixer because they are not pull-request-ready. For `observed` source-patch plans, plan to say in the final `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. The plan must explain how the proposed code change addresses the observed issue evidence, call out any prior Fixer patch that should be improved or replaced, reject awkward control flow such as avoidable `goto` if there is a cleaner bounded alternative, name any local helper APIs or maintainer conventions the patch should follow, and keep the intended maintainer-facing explanation clear enough that someone unfamiliar with the local complaint wording can still follow the fix. In `## Validation`, name the reproducible configure/build/test entrypoint you will try from the workspace root before any focused leaf compile or smoke check, and include one bounded independent reproduction attempt for the collected failure signal when it is safe and cheap. Do not plan to claim `reproduced` unless that reproduction command or test can actually show the failure.

## Patch Pass

You are working on a bounded fixer proposal.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Produce the smallest reasonable patch for the target repository, keep the change upstreamable, prefer the clearest control flow available, and do not keep avoidable `goto` when a simpler structure would read better. Before introducing new file, process, allocation, locking, networking, or platform APIs, inspect nearby code and project contribution docs for existing helpers or compatibility wrappers and use those local patterns unless you can explain why they do not fit. Validate from a reproducible workspace-root entrypoint before falling back to focused leaf commands; if a build or test cannot run, report the exact command, the exact blocker, and any narrower check you ran instead. During validation, also try one bounded independent reproduction of the collected failure signal when it is safe and cheap, such as a failing test, smoke command, perf/strace comparison, or before/after runtime check. Only use `reproduced` if that command or test actually reproduced the failure; otherwise keep `observed` and report the reproduction blocker. The final explanation must connect the observed issue evidence to the actual code change, not just paraphrase the diff. Write like a maintainer is going to read the patch mail cold: explain the bug in plain language, define subsystem-specific jargon the first time you need it, and make the causal story obvious. Explicitly classify evidence confidence as `reproduced`, `observed`, or `inferred`: `reproduced` means you reproduced the failure locally; `observed` means Fixer has direct crash/log/trace evidence but you did not independently reproduce it; `inferred` means the source patch is not pull-request-ready, so do not leave a source diff unless you first gather stronger observed/reproduced evidence; otherwise return a no-patch diagnosis/report. For any source-changing `observed` patch, say explicitly in `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. If you introduce non-obvious state translation, index remapping, or backend split logic, add a short source comment that explains the invariant being preserved.

Start by explaining the likely root cause from the collected perf, strace, and /proc evidence. If you cannot land a safe patch, leave a diagnosis that is strong enough for an upstream bug report.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. 

Keep the change narrowly scoped and summarize validation clearly.

In every authoring pass, your final response must start with `Subject: <single-line git commit subject>` and then include these markdown sections exactly:

## Commit Message
A short upstream-friendly explanation of what changed and why. Write it in plain language that a maintainer can follow without local complaint context. If you use subsystem jargon, define it immediately.

## Evidence Confidence
Exactly one word: `reproduced`, `observed`, or `inferred`. Use `reproduced` only when you reproduced the failure locally with a command or test, and include that command/test in `## Validation`. Use `observed` when Fixer has direct crash/log/trace evidence but you did not independently reproduce it. If `## Git Add Paths` lists source files for an `observed` patch, `## Issue Connection` must explicitly say the failure was observed by Fixer and not independently reproduced. Use `inferred` for profiler/strace/indirect evidence; inferred responses may be no-patch diagnoses or reports, but inferred source patches are not pull-request-ready until stronger evidence is gathered.

## Issue Connection
Write this as maintainer-facing patch mail, not as local Fixer notes. Cover four things explicitly in readable sentences: the user-visible symptom or the exact collected signal, the code-level cause or the cautious inference from evidence, the specific change you made, and the expected effect. Do not invent a reproducer, command line, crash, or user-visible failure that is not present in the evidence bundle. If the evidence is direct-but-not-reproduced, say it was observed by Fixer and not independently reproduced. If the evidence is indirect and you did not gather stronger evidence, do not leave a source diff; write a no-patch diagnosis/report instead. Include an explicit effect sentence such as `The expected effect is ...`, `This should reduce ...`, or `This prevents ...` for source patches. If the logic is non-obvious in code, mention that you added a short explanatory comment.

## Git Add Paths
List the repo-relative paths that belong in the final patch, one per line. Use `None` only when you intentionally made no source changes. Include intentionally new files, and do not list generated build artifacts.

## Validation
List the checks you ran, or say clearly that you could not run them. Include the independent reproduction command/test and result when `## Evidence Confidence` is `reproduced`; if reproduction was attempted but blocked, name the exact blocker and keep confidence at `observed` or `inferred`.

Before editing, read the plan at `./plan-output.txt` and follow it unless the code proves part of it wrong. If you change course, say so explicitly in the final write-up instead of silently drifting from the plan.

## Review Pass 1

You are reviewing a freshly generated fixer patch.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Review the first patch pass. The original pre-edit snapshot is available at `./source` for diffing.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. The latest author response is at `./patch-output.txt`. Inspect the current code and changed paths like a strict code reviewer. Focus on correctness, regressions, maintainability, awkward control flow such as avoidable `goto`, missing validation, weak or non-gittable commit message text, and explanations that fail to connect the observed issue evidence to the code change. Also review the maintainer experience: the patch mail should be easy to accept upstream, the user-visible bug should be explained in plain language, subsystem-specific jargon should be defined when first used, and any non-obvious state translation or index remapping in code should have a short explanatory comment. Reject patches that omit `## Evidence Confidence`, use anything other than `reproduced`, `observed`, or `inferred`, or sound more certain than that evidence level allows. Reject patches that claim `reproduced` unless `## Validation` names the concrete reproduction command or test and its result. Reject patches that invent a reproducer, command line, crash, or user-visible failure not present in the evidence bundle; indirect profiler or strace evidence may justify a cautious mitigation, but the author must say it is indirect instead of presenting it as a confirmed upstream bug. Reject patches that introduce generic libc/std APIs when nearby code or project docs provide a local compat/helper API for the same job, unless the author explicitly justifies the exception. Reject validation that only reports a leaf object/syntax build when a project-level configure/build/test entrypoint exists and was not attempted; if a full build cannot run, the author must show the exact failed command and blocker.

Do not apply code changes in this pass.

Return a short markdown review report. The first non-empty line must be exactly one of:

RESULT: ok
RESULT: fix-needed

If you choose `RESULT: fix-needed`, add a `## Findings` section with concrete, actionable items.

Response

## Plan Pass

## Problem
Fixer observed `/usr/sbin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock` sleeping with 185 threads, 0.1% CPU, kernel hot path `__schedule`, and embedded strace excerpts dominated by `FUTEX_WAIT_PRIVATE` plus `waitid(P_PIDFD, ...)`. The bundle labels this `socket-churn`, but the included syscall excerpt does not show socket retry churn, and the raw artifact directory referenced by `evidence.json` is not present in this sandbox.

## Evidence Confidence
inferred

## Proposed Subject
No source patch: report an evidence-limited diagnosis for an idle/futex-heavy `dockerd` profile.

## Patch Plan
Do not edit files. The available evidence is indirect profiler/strace excerpt data and is compatible with normal idle Go daemon goroutines blocked in futex waits, not a demonstrated upstream `dockerd` bug.

I inspected the application entrypoint first: `engine/cmd/dockerd/daemon.go` calls `loadListeners`, which delegates `fd://` handling to `engine/daemon/listeners/listeners_linux.go`. Relevant local helpers/conventions are `daemon/listeners.Init`, `go-systemd/activation` for socket activation, `docker/go-connections/sockets`, `homedir.StickRuntimeDirContents`, and `containerd/log` via `log.G(ctx)`. Runtime futex behavior remains a secondary investigation target unless stronger evidence proves a runtime bug.

Prior Fixer output should be improved by replacing any misleading “socket churn loop” summary with a clear no-patch diagnosis. Keep the prior no-source-change conclusion; no awkward control flow such as `goto` is planned because no code change is justified.

## Risks
A source patch from this evidence would likely invent a failure mode. Changing `fd://` listener or containerd code without syscall evidence of actual socket churn could regress systemd socket activation or daemon startup behavior.

## Validation
Before any focused checks, try the Debian workspace entrypoint: `debian/rules build` from the workspace root.

Bounded independent reproduction attempt: inspect/count the raw strace artifact for repeated socket syscalls or runnable CPU churn if the referenced `/var/lib/fixer/investigations/.../strace.log` exists; if it remains unavailable, record that reproduction is blocked and do not claim `reproduced`.

If later evidence justifies a listener patch, run `cd engine && TESTDIRS=./cmd/dockerd TESTFLAGS='-test.run TestLoadListenerNoAddr -count=1' ./hack/test/unit`.

## Patch Pass

Subject: dockerd: Diagnose idle futex profile without patch

## Commit Message
No source change is proposed. The collected perf, strace, and `/proc` evidence points to an idle Go daemon: `dockerd` was sleeping, using 0.1% CPU, sampled in the kernel scheduler, and blocked in futex waits. A futex is the Linux wait primitive used by the Go runtime for parked goroutines and synchronization, so this evidence is not enough to justify an upstream daemon code change.

## Evidence Confidence
inferred

## Issue Connection
The exact collected signal is `/usr/sbin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock` with 185 threads, process state `S (sleeping)`, hot path `__schedule`, a kernel stack in `futex_wait`, and embedded strace lines containing 22 futex waits and 2 `waitid(P_PIDFD, ...)` calls. Although the bundle classifies the profile as `socket-churn`, the embedded strace excerpt contains 0 socket-related syscall lines, and the raw investigation directory needed to verify the classifier is absent.

The cautious code-level inference is that the sampled daemon was mostly parked in normal Go/runtime or child-process waits, not demonstrably spinning in a Docker listener, containerd client, or socket retry loop. I followed the saved plan and inspected the application entrypoint first: `engine/cmd/dockerd/daemon.go` calls `loadListeners`, which uses `daemon/listeners.Init`; the Linux listener path uses `go-systemd/activation` for `fd://` socket activation, `docker/go-connections/sockets` for socket creation, `homedir.StickRuntimeDirContents`, and `containerd/log` via `log.G(ctx)`. I also inspected the adjacent `libcontainerd/remote` code, which follows containerd client wrappers and `cio` helpers.

The specific change made is none. The expected effect is to avoid landing a speculative source patch for indirect profiler evidence that does not identify a faulty upstream subsystem. This improves the prior Fixer wording by not calling the situation a confirmed socket churn loop.

## Git Add Paths
None

## Validation
`debian/rules build` from the workspace root failed before compilation because the Debian golang debhelper addon is missing:
`dh: error: unable to load addon golang: Can't locate Debian/Debhelper/Sequence/golang.pm ...`

Bounded independent reproduction attempt:
`find /var/lib/fixer/investigations/2026-05-06T20-26-06.323932540+00-00-dockerd-b732bcc6a3ff -maxdepth 1 -type f -print`
failed with `No such file or directory`, so I could not inspect the full raw strace for actual socket churn.

Narrower evidence check:
`jq -r '.opportunity.evidence.details.strace_excerpt[]?' .../evidence.json | awk ...`
reported `embedded_strace_lines=24`, `futex_lines=22`, `waitid_lines=2`, `socket_related_lines=0`.

Focused fallback:
`cd engine && TESTDIRS=./cmd/dockerd TESTFLAGS='-test.run TestLoadListenerNoAddr -count=1' ./hack/test/unit`
failed because `gotestsum` is not installed after the harness selected `github.com/docker/docker/cmd/dockerd`.

`git status --short` is clean.

## Review Pass 1

RESULT: ok

No findings.

The first patch pass correctly leaves the worktree clean for `inferred` evidence. The author output includes the required `## Evidence Confidence` section, uses an allowed value, does not claim reproduction, and does not leave a speculative source diff.

The diagnosis matches the bundle: the concrete excerpts show a sleeping `dockerd`, 0.1% CPU, scheduler/futex waits, and embedded strace lines with futex/waitid rather than socket syscalls. The validation reports the project-level `debian/rules build` attempt and exact blocker, plus a bounded reproduction attempt blocked by the missing raw investigation directory.

diagnosis-only report

report

dockerd likely remains stuck in a socket churn loop. A diagnosis report and patch proposal were created locally.

state: readycreated: 2026-05-13 14:11 UTCvalidation: ready
Published session

Prompt

## Plan Pass

You are planning a fixer patch before any edits happen.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. The original pre-edit snapshot is available at `./source` if you need to inspect it. For interpreter processes, plan from the script/application entrypoint evidence first and include the runtime only as a second investigation target unless the evidence proves a runtime bug.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. Inspect the relevant code, nearby callers, project contribution docs, and local helper/compat APIs, but do not edit files in this pass.

Return a short markdown plan with these exact sections:

## Problem
## Evidence Confidence
## Proposed Subject
## Patch Plan
## Risks
## Validation

Classify `## Evidence Confidence` as exactly one of `reproduced`, `observed`, or `inferred`. Use `inferred` only for a no-patch diagnosis/report plan unless you can name the extra evidence you will collect before editing; inferred source patches are blocked by Fixer because they are not pull-request-ready. For `observed` source-patch plans, plan to say in the final `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. The plan must explain how the proposed code change addresses the observed issue evidence, call out any prior Fixer patch that should be improved or replaced, reject awkward control flow such as avoidable `goto` if there is a cleaner bounded alternative, name any local helper APIs or maintainer conventions the patch should follow, and keep the intended maintainer-facing explanation clear enough that someone unfamiliar with the local complaint wording can still follow the fix. In `## Validation`, name the reproducible configure/build/test entrypoint you will try from the workspace root before any focused leaf compile or smoke check, and include one bounded independent reproduction attempt for the collected failure signal when it is safe and cheap. Do not plan to claim `reproduced` unless that reproduction command or test can actually show the failure.

## Patch Pass

You are working on a bounded fixer proposal.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Produce the smallest reasonable patch for the target repository, keep the change upstreamable, prefer the clearest control flow available, and do not keep avoidable `goto` when a simpler structure would read better. Before introducing new file, process, allocation, locking, networking, or platform APIs, inspect nearby code and project contribution docs for existing helpers or compatibility wrappers and use those local patterns unless you can explain why they do not fit. Validate from a reproducible workspace-root entrypoint before falling back to focused leaf commands; if a build or test cannot run, report the exact command, the exact blocker, and any narrower check you ran instead. During validation, also try one bounded independent reproduction of the collected failure signal when it is safe and cheap, such as a failing test, smoke command, perf/strace comparison, or before/after runtime check. Only use `reproduced` if that command or test actually reproduced the failure; otherwise keep `observed` and report the reproduction blocker. The final explanation must connect the observed issue evidence to the actual code change, not just paraphrase the diff. Write like a maintainer is going to read the patch mail cold: explain the bug in plain language, define subsystem-specific jargon the first time you need it, and make the causal story obvious. Explicitly classify evidence confidence as `reproduced`, `observed`, or `inferred`: `reproduced` means you reproduced the failure locally; `observed` means Fixer has direct crash/log/trace evidence but you did not independently reproduce it; `inferred` means the source patch is not pull-request-ready, so do not leave a source diff unless you first gather stronger observed/reproduced evidence; otherwise return a no-patch diagnosis/report. For any source-changing `observed` patch, say explicitly in `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. If you introduce non-obvious state translation, index remapping, or backend split logic, add a short source comment that explains the invariant being preserved.

Start by explaining the likely root cause from the collected perf, strace, and /proc evidence. If you cannot land a safe patch, leave a diagnosis that is strong enough for an upstream bug report.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. 

Keep the change narrowly scoped and summarize validation clearly.

In every authoring pass, your final response must start with `Subject: <single-line git commit subject>` and then include these markdown sections exactly:

## Commit Message
A short upstream-friendly explanation of what changed and why. Write it in plain language that a maintainer can follow without local complaint context. If you use subsystem jargon, define it immediately.

## Evidence Confidence
Exactly one word: `reproduced`, `observed`, or `inferred`. Use `reproduced` only when you reproduced the failure locally with a command or test, and include that command/test in `## Validation`. Use `observed` when Fixer has direct crash/log/trace evidence but you did not independently reproduce it. If `## Git Add Paths` lists source files for an `observed` patch, `## Issue Connection` must explicitly say the failure was observed by Fixer and not independently reproduced. Use `inferred` for profiler/strace/indirect evidence; inferred responses may be no-patch diagnoses or reports, but inferred source patches are not pull-request-ready until stronger evidence is gathered.

## Issue Connection
Write this as maintainer-facing patch mail, not as local Fixer notes. Cover four things explicitly in readable sentences: the user-visible symptom or the exact collected signal, the code-level cause or the cautious inference from evidence, the specific change you made, and the expected effect. Do not invent a reproducer, command line, crash, or user-visible failure that is not present in the evidence bundle. If the evidence is direct-but-not-reproduced, say it was observed by Fixer and not independently reproduced. If the evidence is indirect and you did not gather stronger evidence, do not leave a source diff; write a no-patch diagnosis/report instead. Include an explicit effect sentence such as `The expected effect is ...`, `This should reduce ...`, or `This prevents ...` for source patches. If the logic is non-obvious in code, mention that you added a short explanatory comment.

## Git Add Paths
List the repo-relative paths that belong in the final patch, one per line. Use `None` only when you intentionally made no source changes. Include intentionally new files, and do not list generated build artifacts.

## Validation
List the checks you ran, or say clearly that you could not run them. Include the independent reproduction command/test and result when `## Evidence Confidence` is `reproduced`; if reproduction was attempted but blocked, name the exact blocker and keep confidence at `observed` or `inferred`.

Before editing, read the plan at `./plan-output.txt` and follow it unless the code proves part of it wrong. If you change course, say so explicitly in the final write-up instead of silently drifting from the plan.

## Review Pass 1

You are reviewing a freshly generated fixer patch.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Review the first patch pass. The original pre-edit snapshot is available at `./source` for diffing.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. The latest author response is at `./patch-output.txt`. Inspect the current code and changed paths like a strict code reviewer. Focus on correctness, regressions, maintainability, awkward control flow such as avoidable `goto`, missing validation, weak or non-gittable commit message text, and explanations that fail to connect the observed issue evidence to the code change. Also review the maintainer experience: the patch mail should be easy to accept upstream, the user-visible bug should be explained in plain language, subsystem-specific jargon should be defined when first used, and any non-obvious state translation or index remapping in code should have a short explanatory comment. Reject patches that omit `## Evidence Confidence`, use anything other than `reproduced`, `observed`, or `inferred`, or sound more certain than that evidence level allows. Reject patches that claim `reproduced` unless `## Validation` names the concrete reproduction command or test and its result. Reject patches that invent a reproducer, command line, crash, or user-visible failure not present in the evidence bundle; indirect profiler or strace evidence may justify a cautious mitigation, but the author must say it is indirect instead of presenting it as a confirmed upstream bug. Reject patches that introduce generic libc/std APIs when nearby code or project docs provide a local compat/helper API for the same job, unless the author explicitly justifies the exception. Reject validation that only reports a leaf object/syntax build when a project-level configure/build/test entrypoint exists and was not attempted; if a full build cannot run, the author must show the exact failed command and blocker.

Do not apply code changes in this pass.

Return a short markdown review report. The first non-empty line must be exactly one of:

RESULT: ok
RESULT: fix-needed

If you choose `RESULT: fix-needed`, add a `## Findings` section with concrete, actionable items.

Response

## Plan Pass

## Problem
Fixer observed `/usr/sbin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock` sleeping with 185 threads, 0.1% CPU, kernel hot path `__schedule`, and embedded strace excerpts dominated by `FUTEX_WAIT_PRIVATE` plus `waitid(P_PIDFD, ...)`. The bundle labels this `socket-churn`, but the included syscall excerpt does not show socket retry churn, and the raw artifact directory referenced by `evidence.json` is not present in this sandbox.

## Evidence Confidence
inferred

## Proposed Subject
No source patch: report an evidence-limited diagnosis for an idle/futex-heavy `dockerd` profile.

## Patch Plan
Do not edit files. The available evidence is indirect profiler/strace excerpt data and is compatible with normal idle Go daemon goroutines blocked in futex waits, not a demonstrated upstream `dockerd` bug.

I inspected the application entrypoint first: `engine/cmd/dockerd/daemon.go` calls `loadListeners`, which delegates `fd://` handling to `engine/daemon/listeners/listeners_linux.go`. Relevant local helpers/conventions are `daemon/listeners.Init`, `go-systemd/activation` for socket activation, `docker/go-connections/sockets`, `homedir.StickRuntimeDirContents`, and `containerd/log` via `log.G(ctx)`. Runtime futex behavior remains a secondary investigation target unless stronger evidence proves a runtime bug.

Prior Fixer output should be improved by replacing any misleading “socket churn loop” summary with a clear no-patch diagnosis. Keep the prior no-source-change conclusion; no awkward control flow such as `goto` is planned because no code change is justified.

## Risks
A source patch from this evidence would likely invent a failure mode. Changing `fd://` listener or containerd code without syscall evidence of actual socket churn could regress systemd socket activation or daemon startup behavior.

## Validation
Before any focused checks, try the Debian workspace entrypoint: `debian/rules build` from the workspace root.

Bounded independent reproduction attempt: inspect/count the raw strace artifact for repeated socket syscalls or runnable CPU churn if the referenced `/var/lib/fixer/investigations/.../strace.log` exists; if it remains unavailable, record that reproduction is blocked and do not claim `reproduced`.

If later evidence justifies a listener patch, run `cd engine && TESTDIRS=./cmd/dockerd TESTFLAGS='-test.run TestLoadListenerNoAddr -count=1' ./hack/test/unit`.

## Patch Pass

Subject: dockerd: Diagnose idle futex profile without patch

## Commit Message
No source change is proposed. The collected perf, strace, and `/proc` evidence points to an idle Go daemon: `dockerd` was sleeping, using 0.1% CPU, sampled in the kernel scheduler, and blocked in futex waits. A futex is the Linux wait primitive used by the Go runtime for parked goroutines and synchronization, so this evidence is not enough to justify an upstream daemon code change.

## Evidence Confidence
inferred

## Issue Connection
The exact collected signal is `/usr/sbin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock` with 185 threads, process state `S (sleeping)`, hot path `__schedule`, a kernel stack in `futex_wait`, and embedded strace lines containing 22 futex waits and 2 `waitid(P_PIDFD, ...)` calls. Although the bundle classifies the profile as `socket-churn`, the embedded strace excerpt contains 0 socket-related syscall lines, and the raw investigation directory needed to verify the classifier is absent.

The cautious code-level inference is that the sampled daemon was mostly parked in normal Go/runtime or child-process waits, not demonstrably spinning in a Docker listener, containerd client, or socket retry loop. I followed the saved plan and inspected the application entrypoint first: `engine/cmd/dockerd/daemon.go` calls `loadListeners`, which uses `daemon/listeners.Init`; the Linux listener path uses `go-systemd/activation` for `fd://` socket activation, `docker/go-connections/sockets` for socket creation, `homedir.StickRuntimeDirContents`, and `containerd/log` via `log.G(ctx)`. I also inspected the adjacent `libcontainerd/remote` code, which follows containerd client wrappers and `cio` helpers.

The specific change made is none. The expected effect is to avoid landing a speculative source patch for indirect profiler evidence that does not identify a faulty upstream subsystem. This improves the prior Fixer wording by not calling the situation a confirmed socket churn loop.

## Git Add Paths
None

## Validation
`debian/rules build` from the workspace root failed before compilation because the Debian golang debhelper addon is missing:
`dh: error: unable to load addon golang: Can't locate Debian/Debhelper/Sequence/golang.pm ...`

Bounded independent reproduction attempt:
`find /var/lib/fixer/investigations/2026-05-06T20-26-06.323932540+00-00-dockerd-b732bcc6a3ff -maxdepth 1 -type f -print`
failed with `No such file or directory`, so I could not inspect the full raw strace for actual socket churn.

Narrower evidence check:
`jq -r '.opportunity.evidence.details.strace_excerpt[]?' .../evidence.json | awk ...`
reported `embedded_strace_lines=24`, `futex_lines=22`, `waitid_lines=2`, `socket_related_lines=0`.

Focused fallback:
`cd engine && TESTDIRS=./cmd/dockerd TESTFLAGS='-test.run TestLoadListenerNoAddr -count=1' ./hack/test/unit`
failed because `gotestsum` is not installed after the harness selected `github.com/docker/docker/cmd/dockerd`.

`git status --short` is clean.

## Review Pass 1

RESULT: ok

No findings.

The first patch pass correctly leaves the worktree clean for `inferred` evidence. The author output includes the required `## Evidence Confidence` section, uses an allowed value, does not claim reproduction, and does not leave a speculative source diff.

The diagnosis matches the bundle: the concrete excerpts show a sleeping `dockerd`, 0.1% CPU, scheduler/futex waits, and embedded strace lines with futex/waitid rather than socket syscalls. The validation reports the project-level `debian/rules build` attempt and exact blocker, plus a bounded reproduction attempt blocked by the missing raw investigation directory.

diagnosis-only report

report

dockerd likely remains stuck in a socket churn loop. A diagnosis report and patch proposal were created locally.

state: readycreated: 2026-05-13 12:55 UTCvalidation: ready
Published session

Prompt

## Plan Pass

You are planning a fixer patch before any edits happen.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. The original pre-edit snapshot is available at `./source` if you need to inspect it. For interpreter processes, plan from the script/application entrypoint evidence first and include the runtime only as a second investigation target unless the evidence proves a runtime bug.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. Inspect the relevant code, nearby callers, project contribution docs, and local helper/compat APIs, but do not edit files in this pass.

Return a short markdown plan with these exact sections:

## Problem
## Evidence Confidence
## Proposed Subject
## Patch Plan
## Risks
## Validation

Classify `## Evidence Confidence` as exactly one of `reproduced`, `observed`, or `inferred`. Use `inferred` only for a no-patch diagnosis/report plan unless you can name the extra evidence you will collect before editing; inferred source patches are blocked by Fixer because they are not pull-request-ready. For `observed` source-patch plans, plan to say in the final `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. The plan must explain how the proposed code change addresses the observed issue evidence, call out any prior Fixer patch that should be improved or replaced, reject awkward control flow such as avoidable `goto` if there is a cleaner bounded alternative, name any local helper APIs or maintainer conventions the patch should follow, and keep the intended maintainer-facing explanation clear enough that someone unfamiliar with the local complaint wording can still follow the fix. In `## Validation`, name the reproducible configure/build/test entrypoint you will try from the workspace root before any focused leaf compile or smoke check, and include one bounded independent reproduction attempt for the collected failure signal when it is safe and cheap. Do not plan to claim `reproduced` unless that reproduction command or test can actually show the failure.

## Patch Pass

You are working on a bounded fixer proposal.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Produce the smallest reasonable patch for the target repository, keep the change upstreamable, prefer the clearest control flow available, and do not keep avoidable `goto` when a simpler structure would read better. Before introducing new file, process, allocation, locking, networking, or platform APIs, inspect nearby code and project contribution docs for existing helpers or compatibility wrappers and use those local patterns unless you can explain why they do not fit. Validate from a reproducible workspace-root entrypoint before falling back to focused leaf commands; if a build or test cannot run, report the exact command, the exact blocker, and any narrower check you ran instead. During validation, also try one bounded independent reproduction of the collected failure signal when it is safe and cheap, such as a failing test, smoke command, perf/strace comparison, or before/after runtime check. Only use `reproduced` if that command or test actually reproduced the failure; otherwise keep `observed` and report the reproduction blocker. The final explanation must connect the observed issue evidence to the actual code change, not just paraphrase the diff. Write like a maintainer is going to read the patch mail cold: explain the bug in plain language, define subsystem-specific jargon the first time you need it, and make the causal story obvious. Explicitly classify evidence confidence as `reproduced`, `observed`, or `inferred`: `reproduced` means you reproduced the failure locally; `observed` means Fixer has direct crash/log/trace evidence but you did not independently reproduce it; `inferred` means the source patch is not pull-request-ready, so do not leave a source diff unless you first gather stronger observed/reproduced evidence; otherwise return a no-patch diagnosis/report. For any source-changing `observed` patch, say explicitly in `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. If you introduce non-obvious state translation, index remapping, or backend split logic, add a short source comment that explains the invariant being preserved.

Start by explaining the likely root cause from the collected perf, strace, and /proc evidence. If you cannot land a safe patch, leave a diagnosis that is strong enough for an upstream bug report.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. 

Keep the change narrowly scoped and summarize validation clearly.

In every authoring pass, your final response must start with `Subject: <single-line git commit subject>` and then include these markdown sections exactly:

## Commit Message
A short upstream-friendly explanation of what changed and why. Write it in plain language that a maintainer can follow without local complaint context. If you use subsystem jargon, define it immediately.

## Evidence Confidence
Exactly one word: `reproduced`, `observed`, or `inferred`. Use `reproduced` only when you reproduced the failure locally with a command or test, and include that command/test in `## Validation`. Use `observed` when Fixer has direct crash/log/trace evidence but you did not independently reproduce it. If `## Git Add Paths` lists source files for an `observed` patch, `## Issue Connection` must explicitly say the failure was observed by Fixer and not independently reproduced. Use `inferred` for profiler/strace/indirect evidence; inferred responses may be no-patch diagnoses or reports, but inferred source patches are not pull-request-ready until stronger evidence is gathered.

## Issue Connection
Write this as maintainer-facing patch mail, not as local Fixer notes. Cover four things explicitly in readable sentences: the user-visible symptom or the exact collected signal, the code-level cause or the cautious inference from evidence, the specific change you made, and the expected effect. Do not invent a reproducer, command line, crash, or user-visible failure that is not present in the evidence bundle. If the evidence is direct-but-not-reproduced, say it was observed by Fixer and not independently reproduced. If the evidence is indirect and you did not gather stronger evidence, do not leave a source diff; write a no-patch diagnosis/report instead. Include an explicit effect sentence such as `The expected effect is ...`, `This should reduce ...`, or `This prevents ...` for source patches. If the logic is non-obvious in code, mention that you added a short explanatory comment.

## Git Add Paths
List the repo-relative paths that belong in the final patch, one per line. Use `None` only when you intentionally made no source changes. Include intentionally new files, and do not list generated build artifacts.

## Validation
List the checks you ran, or say clearly that you could not run them. Include the independent reproduction command/test and result when `## Evidence Confidence` is `reproduced`; if reproduction was attempted but blocked, name the exact blocker and keep confidence at `observed` or `inferred`.

Before editing, read the plan at `./plan-output.txt` and follow it unless the code proves part of it wrong. If you change course, say so explicitly in the final write-up instead of silently drifting from the plan.

## Review Pass 1

You are reviewing a freshly generated fixer patch.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Review the first patch pass. The original pre-edit snapshot is available at `./source` for diffing.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. The latest author response is at `./patch-output.txt`. Inspect the current code and changed paths like a strict code reviewer. Focus on correctness, regressions, maintainability, awkward control flow such as avoidable `goto`, missing validation, weak or non-gittable commit message text, and explanations that fail to connect the observed issue evidence to the code change. Also review the maintainer experience: the patch mail should be easy to accept upstream, the user-visible bug should be explained in plain language, subsystem-specific jargon should be defined when first used, and any non-obvious state translation or index remapping in code should have a short explanatory comment. Reject patches that omit `## Evidence Confidence`, use anything other than `reproduced`, `observed`, or `inferred`, or sound more certain than that evidence level allows. Reject patches that claim `reproduced` unless `## Validation` names the concrete reproduction command or test and its result. Reject patches that invent a reproducer, command line, crash, or user-visible failure not present in the evidence bundle; indirect profiler or strace evidence may justify a cautious mitigation, but the author must say it is indirect instead of presenting it as a confirmed upstream bug. Reject patches that introduce generic libc/std APIs when nearby code or project docs provide a local compat/helper API for the same job, unless the author explicitly justifies the exception. Reject validation that only reports a leaf object/syntax build when a project-level configure/build/test entrypoint exists and was not attempted; if a full build cannot run, the author must show the exact failed command and blocker.

Do not apply code changes in this pass.

Return a short markdown review report. The first non-empty line must be exactly one of:

RESULT: ok
RESULT: fix-needed

If you choose `RESULT: fix-needed`, add a `## Findings` section with concrete, actionable items.

Response

## Plan Pass

## Problem
Fixer observed `dockerd -H fd:// --containerd=/run/containerd/containerd.sock` mostly sleeping in futex waits: 185 threads, process state `S`, `total_cpu_percent` 0.1, hot path `__schedule`, and strace excerpts dominated by unfinished `FUTEX_WAIT_PRIVATE` plus a couple `waitid(P_PIDFD, ...)`. The evidence also labels “socket-churn”, but the included syscall excerpt does not show socket retry/churn, and raw artifact files referenced by the JSON were not available in this workspace.

## Evidence Confidence
inferred

## Proposed Subject
No source patch yet: diagnose idle/futex-heavy `dockerd` observation before changing daemon listener or runtime code.

## Patch Plan
Do not edit in this pass. The available evidence is profiler-only/indirect and looks compatible with an idle Go daemon blocked on goroutines or child waits, not a demonstrated user-visible failure.

If more evidence is collected before editing, start from the application entrypoint path: `engine/cmd/dockerd/daemon.go` `loadListeners`, then `engine/daemon/listeners/listeners_linux.go` `listenFD`, because the command line uses `-H fd://`. Treat Go runtime futex behavior as secondary unless new evidence proves a runtime-level problem.

Follow Moby conventions from `engine/CONTRIBUTING.md` and `engine/TESTING.md`: add unit tests for bug fixes, run `gofmt -s -w`, avoid vendor edits, and use existing helpers. Relevant local helpers/conventions found: `daemon/listeners.Init`, `github.com/coreos/go-systemd/v22/activation` for socket activation, `github.com/docker/go-connections/sockets` for socket creation, `homedir.StickRuntimeDirContents`, and `github.com/containerd/log` via `log.G(ctx)`.

No prior Fixer patch for this issue was found in the workspace; Debian quilt patches are present but appear packaging/build/test related. If later evidence identifies a real `fd://N` listener bug, prefer a bounded validation/error branch over awkward `goto` cleanup.

## Risks
Patching from the current evidence would likely invent a bug: sleeping futex waits with 0.1% CPU are normal for an idle Go service. A listener patch could alter systemd socket activation behavior without proving it affects the observed process.

## Validation
Primary workspace entrypoint before focused checks: `debian/rules build`, matching the Debian source package flow.

Focused checks if evidence later justifies listener changes: `cd engine && TESTDIRS=./cmd/dockerd TESTFLAGS='-test.run TestLoadListenerNoAddr -count=1' ./hack/test/unit`.

Bounded independent reproduction attempt: inspect available profiler/trace artifacts for actual repeated socket syscalls or runnable CPU churn; if unavailable, run only the existing fake systemd activation listener test and do not claim reproduction.

## Patch Pass

Subject: dockerd: Diagnose idle futex profile without patch

## Commit Message
No source change is proposed. The collected data points at an idle `dockerd`: the process is sleeping, CPU is 0.1%, the kernel stack is in futex wait, and the strace excerpt shows futex waits plus `waitid`. A futex is the Linux primitive Go uses for blocking goroutines and runtime scheduling, so this is not enough evidence for an upstream daemon bug.

## Evidence Confidence
inferred

## Issue Connection
The collected signal is `/usr/sbin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock` with 185 threads, process state `S (sleeping)`, hot path `__schedule`, and strace dominated by `FUTEX_WAIT_PRIVATE`. The evidence bundle labels this “socket-churn”, but the included syscall excerpt does not show repeated socket calls, and the raw strace/proc artifact directory was not available to verify that classifier.

Following the saved plan, I inspected the `fd://` listener path first: `engine/cmd/dockerd/daemon.go` delegates to `engine/daemon/listeners/listeners_linux.go`, which already uses the local `daemon/listeners.Init` path, `go-systemd/activation` for socket activation, `go-connections/sockets` for socket creation, `homedir.StickRuntimeDirContents`, and `containerd/log` via `log.G(ctx)`. I also checked Moby contribution/test docs; they require focused tests for bug fixes and `gofmt`, but there is no demonstrated bug to test.

The specific change made is none. The expected effect is to avoid landing a speculative source patch for what currently looks like normal idle Go runtime blocking rather than a proven listener, containerd, or socket retry defect.

## Git Add Paths
None

## Validation
`debian/rules build` from the workspace root failed before compilation because the environment lacks the Debian golang debhelper addon: `Can't locate Debian/Debhelper/Sequence/golang.pm`.

Independent reproduction attempt was blocked: the evidence raw artifact directory `/var/lib/fixer/investigations/2026-05-06T20-26-06.323932540+00-00-dockerd-b732bcc6a3ff` does not exist in this sandbox, so I could not inspect the full strace for actual socket churn.

Focused checks attempted:
`TESTDIRS=./cmd/dockerd TESTFLAGS='-test.run TestLoadListenerNoAddr -count=1' ./hack/test/unit` failed because `gotestsum` is not installed.
`go test -tags 'netgo journald' -run TestLoadListenerNoAddr -count=1 ./cmd/dockerd` failed due missing dependency resolution and unset cache/home.
A retry through a temporary GOPATH symlink under `/tmp` still failed because this Debian source workspace does not include all required dependency trees locally.

`git status --short` is clean.

## Review Pass 1

RESULT: ok

The patch pass leaves the worktree clean and correctly treats the evidence as `inferred`. That matches the bundle: the concrete excerpts show a sleeping `dockerd` with futex waits and low CPU, while the “socket-churn” classifier is not substantiated by the included syscall excerpt.

The author output includes the required `## Evidence Confidence` section, avoids claiming reproduction, documents the workspace-root validation attempt and blockers, and names the relevant local conventions/helpers in the inspected `fd://` listener path. No source diff is present, which is the right outcome for indirect profiler/strace evidence without stronger observed or reproduced failure data.

diagnosis-only report

report

dockerd likely remains stuck in a socket churn loop. A diagnosis report and patch proposal were created locally.

state: readycreated: 2026-05-13 12:55 UTCvalidation: ready
Published session

Prompt

## Plan Pass

You are planning a fixer patch before any edits happen.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. The original pre-edit snapshot is available at `./source` if you need to inspect it. For interpreter processes, plan from the script/application entrypoint evidence first and include the runtime only as a second investigation target unless the evidence proves a runtime bug.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. Inspect the relevant code, nearby callers, project contribution docs, and local helper/compat APIs, but do not edit files in this pass.

Return a short markdown plan with these exact sections:

## Problem
## Evidence Confidence
## Proposed Subject
## Patch Plan
## Risks
## Validation

Classify `## Evidence Confidence` as exactly one of `reproduced`, `observed`, or `inferred`. Use `inferred` only for a no-patch diagnosis/report plan unless you can name the extra evidence you will collect before editing; inferred source patches are blocked by Fixer because they are not pull-request-ready. For `observed` source-patch plans, plan to say in the final `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. The plan must explain how the proposed code change addresses the observed issue evidence, call out any prior Fixer patch that should be improved or replaced, reject awkward control flow such as avoidable `goto` if there is a cleaner bounded alternative, name any local helper APIs or maintainer conventions the patch should follow, and keep the intended maintainer-facing explanation clear enough that someone unfamiliar with the local complaint wording can still follow the fix. In `## Validation`, name the reproducible configure/build/test entrypoint you will try from the workspace root before any focused leaf compile or smoke check, and include one bounded independent reproduction attempt for the collected failure signal when it is safe and cheap. Do not plan to claim `reproduced` unless that reproduction command or test can actually show the failure.

## Patch Pass

You are working on a bounded fixer proposal.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Produce the smallest reasonable patch for the target repository, keep the change upstreamable, prefer the clearest control flow available, and do not keep avoidable `goto` when a simpler structure would read better. Before introducing new file, process, allocation, locking, networking, or platform APIs, inspect nearby code and project contribution docs for existing helpers or compatibility wrappers and use those local patterns unless you can explain why they do not fit. Validate from a reproducible workspace-root entrypoint before falling back to focused leaf commands; if a build or test cannot run, report the exact command, the exact blocker, and any narrower check you ran instead. During validation, also try one bounded independent reproduction of the collected failure signal when it is safe and cheap, such as a failing test, smoke command, perf/strace comparison, or before/after runtime check. Only use `reproduced` if that command or test actually reproduced the failure; otherwise keep `observed` and report the reproduction blocker. The final explanation must connect the observed issue evidence to the actual code change, not just paraphrase the diff. Write like a maintainer is going to read the patch mail cold: explain the bug in plain language, define subsystem-specific jargon the first time you need it, and make the causal story obvious. Explicitly classify evidence confidence as `reproduced`, `observed`, or `inferred`: `reproduced` means you reproduced the failure locally; `observed` means Fixer has direct crash/log/trace evidence but you did not independently reproduce it; `inferred` means the source patch is not pull-request-ready, so do not leave a source diff unless you first gather stronger observed/reproduced evidence; otherwise return a no-patch diagnosis/report. For any source-changing `observed` patch, say explicitly in `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. If you introduce non-obvious state translation, index remapping, or backend split logic, add a short source comment that explains the invariant being preserved.

Start by explaining the likely root cause from the collected perf, strace, and /proc evidence. If you cannot land a safe patch, leave a diagnosis that is strong enough for an upstream bug report.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. 

Keep the change narrowly scoped and summarize validation clearly.

In every authoring pass, your final response must start with `Subject: <single-line git commit subject>` and then include these markdown sections exactly:

## Commit Message
A short upstream-friendly explanation of what changed and why. Write it in plain language that a maintainer can follow without local complaint context. If you use subsystem jargon, define it immediately.

## Evidence Confidence
Exactly one word: `reproduced`, `observed`, or `inferred`. Use `reproduced` only when you reproduced the failure locally with a command or test, and include that command/test in `## Validation`. Use `observed` when Fixer has direct crash/log/trace evidence but you did not independently reproduce it. If `## Git Add Paths` lists source files for an `observed` patch, `## Issue Connection` must explicitly say the failure was observed by Fixer and not independently reproduced. Use `inferred` for profiler/strace/indirect evidence; inferred responses may be no-patch diagnoses or reports, but inferred source patches are not pull-request-ready until stronger evidence is gathered.

## Issue Connection
Write this as maintainer-facing patch mail, not as local Fixer notes. Cover four things explicitly in readable sentences: the user-visible symptom or the exact collected signal, the code-level cause or the cautious inference from evidence, the specific change you made, and the expected effect. Do not invent a reproducer, command line, crash, or user-visible failure that is not present in the evidence bundle. If the evidence is direct-but-not-reproduced, say it was observed by Fixer and not independently reproduced. If the evidence is indirect and you did not gather stronger evidence, do not leave a source diff; write a no-patch diagnosis/report instead. Include an explicit effect sentence such as `The expected effect is ...`, `This should reduce ...`, or `This prevents ...` for source patches. If the logic is non-obvious in code, mention that you added a short explanatory comment.

## Git Add Paths
List the repo-relative paths that belong in the final patch, one per line. Use `None` only when you intentionally made no source changes. Include intentionally new files, and do not list generated build artifacts.

## Validation
List the checks you ran, or say clearly that you could not run them. Include the independent reproduction command/test and result when `## Evidence Confidence` is `reproduced`; if reproduction was attempted but blocked, name the exact blocker and keep confidence at `observed` or `inferred`.

Before editing, read the plan at `./plan-output.txt` and follow it unless the code proves part of it wrong. If you change course, say so explicitly in the final write-up instead of silently drifting from the plan.

## Review Pass 1

You are reviewing a freshly generated fixer patch.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Review the first patch pass. The original pre-edit snapshot is available at `./source` for diffing.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. The latest author response is at `./patch-output.txt`. Inspect the current code and changed paths like a strict code reviewer. Focus on correctness, regressions, maintainability, awkward control flow such as avoidable `goto`, missing validation, weak or non-gittable commit message text, and explanations that fail to connect the observed issue evidence to the code change. Also review the maintainer experience: the patch mail should be easy to accept upstream, the user-visible bug should be explained in plain language, subsystem-specific jargon should be defined when first used, and any non-obvious state translation or index remapping in code should have a short explanatory comment. Reject patches that omit `## Evidence Confidence`, use anything other than `reproduced`, `observed`, or `inferred`, or sound more certain than that evidence level allows. Reject patches that claim `reproduced` unless `## Validation` names the concrete reproduction command or test and its result. Reject patches that invent a reproducer, command line, crash, or user-visible failure not present in the evidence bundle; indirect profiler or strace evidence may justify a cautious mitigation, but the author must say it is indirect instead of presenting it as a confirmed upstream bug. Reject patches that introduce generic libc/std APIs when nearby code or project docs provide a local compat/helper API for the same job, unless the author explicitly justifies the exception. Reject validation that only reports a leaf object/syntax build when a project-level configure/build/test entrypoint exists and was not attempted; if a full build cannot run, the author must show the exact failed command and blocker.

Do not apply code changes in this pass.

Return a short markdown review report. The first non-empty line must be exactly one of:

RESULT: ok
RESULT: fix-needed

If you choose `RESULT: fix-needed`, add a `## Findings` section with concrete, actionable items.

Response

## Plan Pass

## Problem
Fixer observed `dockerd -H fd:// --containerd=/run/containerd/containerd.sock` mostly sleeping in futex waits: 185 threads, process state `S`, `total_cpu_percent` 0.1, hot path `__schedule`, and strace excerpts dominated by unfinished `FUTEX_WAIT_PRIVATE` plus a couple `waitid(P_PIDFD, ...)`. The evidence also labels “socket-churn”, but the included syscall excerpt does not show socket retry/churn, and raw artifact files referenced by the JSON were not available in this workspace.

## Evidence Confidence
inferred

## Proposed Subject
No source patch yet: diagnose idle/futex-heavy `dockerd` observation before changing daemon listener or runtime code.

## Patch Plan
Do not edit in this pass. The available evidence is profiler-only/indirect and looks compatible with an idle Go daemon blocked on goroutines or child waits, not a demonstrated user-visible failure.

If more evidence is collected before editing, start from the application entrypoint path: `engine/cmd/dockerd/daemon.go` `loadListeners`, then `engine/daemon/listeners/listeners_linux.go` `listenFD`, because the command line uses `-H fd://`. Treat Go runtime futex behavior as secondary unless new evidence proves a runtime-level problem.

Follow Moby conventions from `engine/CONTRIBUTING.md` and `engine/TESTING.md`: add unit tests for bug fixes, run `gofmt -s -w`, avoid vendor edits, and use existing helpers. Relevant local helpers/conventions found: `daemon/listeners.Init`, `github.com/coreos/go-systemd/v22/activation` for socket activation, `github.com/docker/go-connections/sockets` for socket creation, `homedir.StickRuntimeDirContents`, and `github.com/containerd/log` via `log.G(ctx)`.

No prior Fixer patch for this issue was found in the workspace; Debian quilt patches are present but appear packaging/build/test related. If later evidence identifies a real `fd://N` listener bug, prefer a bounded validation/error branch over awkward `goto` cleanup.

## Risks
Patching from the current evidence would likely invent a bug: sleeping futex waits with 0.1% CPU are normal for an idle Go service. A listener patch could alter systemd socket activation behavior without proving it affects the observed process.

## Validation
Primary workspace entrypoint before focused checks: `debian/rules build`, matching the Debian source package flow.

Focused checks if evidence later justifies listener changes: `cd engine && TESTDIRS=./cmd/dockerd TESTFLAGS='-test.run TestLoadListenerNoAddr -count=1' ./hack/test/unit`.

Bounded independent reproduction attempt: inspect available profiler/trace artifacts for actual repeated socket syscalls or runnable CPU churn; if unavailable, run only the existing fake systemd activation listener test and do not claim reproduction.

## Patch Pass

Subject: dockerd: Diagnose idle futex profile without patch

## Commit Message
No source change is proposed. The collected data points at an idle `dockerd`: the process is sleeping, CPU is 0.1%, the kernel stack is in futex wait, and the strace excerpt shows futex waits plus `waitid`. A futex is the Linux primitive Go uses for blocking goroutines and runtime scheduling, so this is not enough evidence for an upstream daemon bug.

## Evidence Confidence
inferred

## Issue Connection
The collected signal is `/usr/sbin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock` with 185 threads, process state `S (sleeping)`, hot path `__schedule`, and strace dominated by `FUTEX_WAIT_PRIVATE`. The evidence bundle labels this “socket-churn”, but the included syscall excerpt does not show repeated socket calls, and the raw strace/proc artifact directory was not available to verify that classifier.

Following the saved plan, I inspected the `fd://` listener path first: `engine/cmd/dockerd/daemon.go` delegates to `engine/daemon/listeners/listeners_linux.go`, which already uses the local `daemon/listeners.Init` path, `go-systemd/activation` for socket activation, `go-connections/sockets` for socket creation, `homedir.StickRuntimeDirContents`, and `containerd/log` via `log.G(ctx)`. I also checked Moby contribution/test docs; they require focused tests for bug fixes and `gofmt`, but there is no demonstrated bug to test.

The specific change made is none. The expected effect is to avoid landing a speculative source patch for what currently looks like normal idle Go runtime blocking rather than a proven listener, containerd, or socket retry defect.

## Git Add Paths
None

## Validation
`debian/rules build` from the workspace root failed before compilation because the environment lacks the Debian golang debhelper addon: `Can't locate Debian/Debhelper/Sequence/golang.pm`.

Independent reproduction attempt was blocked: the evidence raw artifact directory `/var/lib/fixer/investigations/2026-05-06T20-26-06.323932540+00-00-dockerd-b732bcc6a3ff` does not exist in this sandbox, so I could not inspect the full strace for actual socket churn.

Focused checks attempted:
`TESTDIRS=./cmd/dockerd TESTFLAGS='-test.run TestLoadListenerNoAddr -count=1' ./hack/test/unit` failed because `gotestsum` is not installed.
`go test -tags 'netgo journald' -run TestLoadListenerNoAddr -count=1 ./cmd/dockerd` failed due missing dependency resolution and unset cache/home.
A retry through a temporary GOPATH symlink under `/tmp` still failed because this Debian source workspace does not include all required dependency trees locally.

`git status --short` is clean.

## Review Pass 1

RESULT: ok

The patch pass leaves the worktree clean and correctly treats the evidence as `inferred`. That matches the bundle: the concrete excerpts show a sleeping `dockerd` with futex waits and low CPU, while the “socket-churn” classifier is not substantiated by the included syscall excerpt.

The author output includes the required `## Evidence Confidence` section, avoids claiming reproduction, documents the workspace-root validation attempt and blockers, and names the relevant local conventions/helpers in the inspected `fd://` listener path. No source diff is present, which is the right outcome for indirect profiler/strace evidence without stronger observed or reproduced failure data.

diagnosis-only report

report

dockerd likely remains stuck in a socket churn loop. A diagnosis report and patch proposal were created locally.

state: readycreated: 2026-05-13 11:10 UTCvalidation: ready
Published session

Prompt

## Plan Pass

You are planning a fixer patch before any edits happen.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. The original pre-edit snapshot is available at `./source` if you need to inspect it. For interpreter processes, plan from the script/application entrypoint evidence first and include the runtime only as a second investigation target unless the evidence proves a runtime bug.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. Inspect the relevant code, nearby callers, project contribution docs, and local helper/compat APIs, but do not edit files in this pass.

Return a short markdown plan with these exact sections:

## Problem
## Evidence Confidence
## Proposed Subject
## Patch Plan
## Risks
## Validation

Classify `## Evidence Confidence` as exactly one of `reproduced`, `observed`, or `inferred`. Use `inferred` only for a no-patch diagnosis/report plan unless you can name the extra evidence you will collect before editing; inferred source patches are blocked by Fixer because they are not pull-request-ready. For `observed` source-patch plans, plan to say in the final `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. The plan must explain how the proposed code change addresses the observed issue evidence, call out any prior Fixer patch that should be improved or replaced, reject awkward control flow such as avoidable `goto` if there is a cleaner bounded alternative, name any local helper APIs or maintainer conventions the patch should follow, and keep the intended maintainer-facing explanation clear enough that someone unfamiliar with the local complaint wording can still follow the fix. In `## Validation`, name the reproducible configure/build/test entrypoint you will try from the workspace root before any focused leaf compile or smoke check, and include one bounded independent reproduction attempt for the collected failure signal when it is safe and cheap. Do not plan to claim `reproduced` unless that reproduction command or test can actually show the failure.

## Patch Pass

You are working on a bounded fixer proposal.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Produce the smallest reasonable patch for the target repository, keep the change upstreamable, prefer the clearest control flow available, and do not keep avoidable `goto` when a simpler structure would read better. Before introducing new file, process, allocation, locking, networking, or platform APIs, inspect nearby code and project contribution docs for existing helpers or compatibility wrappers and use those local patterns unless you can explain why they do not fit. Validate from a reproducible workspace-root entrypoint before falling back to focused leaf commands; if a build or test cannot run, report the exact command, the exact blocker, and any narrower check you ran instead. During validation, also try one bounded independent reproduction of the collected failure signal when it is safe and cheap, such as a failing test, smoke command, perf/strace comparison, or before/after runtime check. Only use `reproduced` if that command or test actually reproduced the failure; otherwise keep `observed` and report the reproduction blocker. The final explanation must connect the observed issue evidence to the actual code change, not just paraphrase the diff. Write like a maintainer is going to read the patch mail cold: explain the bug in plain language, define subsystem-specific jargon the first time you need it, and make the causal story obvious. Explicitly classify evidence confidence as `reproduced`, `observed`, or `inferred`: `reproduced` means you reproduced the failure locally; `observed` means Fixer has direct crash/log/trace evidence but you did not independently reproduce it; `inferred` means the source patch is not pull-request-ready, so do not leave a source diff unless you first gather stronger observed/reproduced evidence; otherwise return a no-patch diagnosis/report. For any source-changing `observed` patch, say explicitly in `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. If you introduce non-obvious state translation, index remapping, or backend split logic, add a short source comment that explains the invariant being preserved.

Start by explaining the likely root cause from the collected perf, strace, and /proc evidence. If you cannot land a safe patch, leave a diagnosis that is strong enough for an upstream bug report.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. 

Keep the change narrowly scoped and summarize validation clearly.

In every authoring pass, your final response must start with `Subject: <single-line git commit subject>` and then include these markdown sections exactly:

## Commit Message
A short upstream-friendly explanation of what changed and why. Write it in plain language that a maintainer can follow without local complaint context. If you use subsystem jargon, define it immediately.

## Evidence Confidence
Exactly one word: `reproduced`, `observed`, or `inferred`. Use `reproduced` only when you reproduced the failure locally with a command or test, and include that command/test in `## Validation`. Use `observed` when Fixer has direct crash/log/trace evidence but you did not independently reproduce it. If `## Git Add Paths` lists source files for an `observed` patch, `## Issue Connection` must explicitly say the failure was observed by Fixer and not independently reproduced. Use `inferred` for profiler/strace/indirect evidence; inferred responses may be no-patch diagnoses or reports, but inferred source patches are not pull-request-ready until stronger evidence is gathered.

## Issue Connection
Write this as maintainer-facing patch mail, not as local Fixer notes. Cover four things explicitly in readable sentences: the user-visible symptom or the exact collected signal, the code-level cause or the cautious inference from evidence, the specific change you made, and the expected effect. Do not invent a reproducer, command line, crash, or user-visible failure that is not present in the evidence bundle. If the evidence is direct-but-not-reproduced, say it was observed by Fixer and not independently reproduced. If the evidence is indirect and you did not gather stronger evidence, do not leave a source diff; write a no-patch diagnosis/report instead. Include an explicit effect sentence such as `The expected effect is ...`, `This should reduce ...`, or `This prevents ...` for source patches. If the logic is non-obvious in code, mention that you added a short explanatory comment.

## Git Add Paths
List the repo-relative paths that belong in the final patch, one per line. Use `None` only when you intentionally made no source changes. Include intentionally new files, and do not list generated build artifacts.

## Validation
List the checks you ran, or say clearly that you could not run them. Include the independent reproduction command/test and result when `## Evidence Confidence` is `reproduced`; if reproduction was attempted but blocked, name the exact blocker and keep confidence at `observed` or `inferred`.

Before editing, read the plan at `./plan-output.txt` and follow it unless the code proves part of it wrong. If you change course, say so explicitly in the final write-up instead of silently drifting from the plan.

## Review Pass 1

You are reviewing a freshly generated fixer patch.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Review the first patch pass. The original pre-edit snapshot is available at `./source` for diffing.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. The latest author response is at `./patch-output.txt`. Inspect the current code and changed paths like a strict code reviewer. Focus on correctness, regressions, maintainability, awkward control flow such as avoidable `goto`, missing validation, weak or non-gittable commit message text, and explanations that fail to connect the observed issue evidence to the code change. Also review the maintainer experience: the patch mail should be easy to accept upstream, the user-visible bug should be explained in plain language, subsystem-specific jargon should be defined when first used, and any non-obvious state translation or index remapping in code should have a short explanatory comment. Reject patches that omit `## Evidence Confidence`, use anything other than `reproduced`, `observed`, or `inferred`, or sound more certain than that evidence level allows. Reject patches that claim `reproduced` unless `## Validation` names the concrete reproduction command or test and its result. Reject patches that invent a reproducer, command line, crash, or user-visible failure not present in the evidence bundle; indirect profiler or strace evidence may justify a cautious mitigation, but the author must say it is indirect instead of presenting it as a confirmed upstream bug. Reject patches that introduce generic libc/std APIs when nearby code or project docs provide a local compat/helper API for the same job, unless the author explicitly justifies the exception. Reject validation that only reports a leaf object/syntax build when a project-level configure/build/test entrypoint exists and was not attempted; if a full build cannot run, the author must show the exact failed command and blocker.

Do not apply code changes in this pass.

Return a short markdown review report. The first non-empty line must be exactly one of:

RESULT: ok
RESULT: fix-needed

If you choose `RESULT: fix-needed`, add a `## Findings` section with concrete, actionable items.

Response

## Plan Pass

## Problem
Fixer observed `dockerd` sleeping with many futex waits during a short profile. The bundle reports 0.1% CPU, `__schedule` as the hot kernel path, process state `S (sleeping)`, and strace excerpts dominated by unfinished `futex(... FUTEX_WAIT_PRIVATE ...)` plus a few `waitid(P_PIDFD, ...)` calls. The classifier labels this as `socket-churn`, but the embedded excerpts do not show an active socket retry loop or a user-visible failure.

## Evidence Confidence
inferred

## Proposed Subject
No patch: diagnose dockerd sleeping/futex profile as insufficient for an upstream source change

## Patch Plan
Do not edit source in this pass unless stronger evidence is collected first. The current evidence is profiler/strace/process-state data without symbols, logs, a reproducer, or a mapped source frame. A source patch would be speculative.

If additional evidence is collected before editing, target `engine/` first because `/usr/sbin/dockerd` is the application entrypoint. Start at `engine/cmd/dockerd/docker.go`, `engine/cmd/dockerd/daemon.go`, then only inspect runtime/containerd paths such as `engine/libcontainerd/remote/client.go` if traces implicate containerd event processing. Avoid treating Go runtime futex parking as a Moby bug unless goroutine stacks or logs identify a daemon-level loop.

Contribution/style docs found: `engine/CONTRIBUTING.md`, `engine/README.md`, `engine/hack/README.md`, and `engine/TESTING.md`. Conventions to follow for any later patch: use `containerd/log` logging, context cancellation patterns, existing daemon/libcontainerd helpers such as `libcontainerd/queue`, add unit tests for bug fixes, and run `gofmt -s`. No relevant file/process/allocation compatibility helper is needed for the no-patch diagnosis.

No prior Fixer patch appears to exist in the workspace; Debian quilt patches are packaging/build/test related and should not be replaced for this evidence.

## Risks
A patch based only on this bundle could “fix” normal Go scheduler parking or idle daemon behavior. The installed version was `28.5.2+dfsg3-2` while the workspace is `28.5.2+dfsg4-1`, and the raw investigation files referenced in the JSON are not present, so address-to-source mapping and independent trace review are limited.

## Validation
Before any future focused check, try the reproducible workspace-root entrypoint `debian/rules build` or, if full package build is too expensive, document that blocker and run the upstream unit entrypoint from `engine/` with `make test-unit`.

Bounded independent reproduction attempt: start a test `dockerd` only if safe root/containerd/systemd prerequisites are available, using isolated `--data-root`, `--exec-root`, `--pidfile`, and a Unix socket, then sample `strace -f -e futex,waitid` and `/proc/$pid/status`. Do not claim `reproduced` unless that command shows the same problematic signal beyond normal idle futex waits.

## Patch Pass

Subject: No patch: diagnose dockerd futex profile

## Commit Message
No source change was made. The collected data points to `dockerd` threads parked in futex waits while the process was sleeping, but it does not identify a Moby code path, retry loop, or user-visible daemon failure that is safe to patch upstream.

## Evidence Confidence
inferred

## Issue Connection
Fixer collected a short profile of `/usr/sbin/dockerd` showing `__schedule` as the hot kernel path, process state `S (sleeping)`, 0.1% CPU, many unfinished `FUTEX_WAIT_PRIVATE` calls, and a few `waitid(P_PIDFD, ...)` calls. That signal is consistent with Go/runtime goroutines or OS threads being parked, but the bundle does not include symbolized daemon frames, goroutine stacks, logs, or socket syscall excerpts that prove a daemon-level socket churn bug.

The cautious code-level conclusion is that there is no identified Moby source defect yet. I followed the saved plan and did not make a speculative source edit. Contribution docs and local conventions checked earlier point to `engine/CONTRIBUTING.md`, `engine/TESTING.md`, `containerd/log`, context cancellation patterns, and `libcontainerd/queue` if future evidence implicates the daemon/containerd event path, but no relevant helper applies to a no-patch diagnosis.

The expected effect is no behavior change. The useful upstream action is to collect stronger evidence: symbolized `dockerd` frames or goroutine dumps correlated with an active retry loop before proposing a patch.

## Git Add Paths
None

## Validation
`dpkg-checkbuilddeps`: failed because many build dependencies are missing, including `dh-golang`, `golang-any`, and the Go library packages required by Debian packaging.

`timeout 60s debian/rules build`: failed before compilation with `Can't locate Debian/Debhelper/Sequence/golang.pm`, confirming the workspace cannot run the package build entrypoint without `dh-golang`.

Independent reproduction attempt: `timeout --signal=TERM 12s strace -f -e trace=futex,waitid ... /usr/sbin/dockerd ...` with isolated `/tmp` roots and network side effects disabled. It was blocked by sandbox ptrace restrictions: `PTRACE_TRACEME: Operation not permitted`, so the futex signal was not reproduced.

A narrower isolated `dockerd` smoke without strace also failed before startup because the sandbox disallowed creating the Unix listener socket: `setsockopt: operation not permitted`.

`git status --short`: clean; no source changes were left.

## Review Pass 1

RESULT: ok

No findings. The author correctly left no source diff for indirect profiler/strace evidence, used `## Evidence Confidence` as `inferred`, avoided inventing a reproducer or confirmed upstream bug, and reported the project-level build/reproduction blockers clearly. `git diff` is empty and `git status --short` is clean.

diagnosis-only report

report

dockerd likely remains stuck in a socket churn loop. A diagnosis report and patch proposal were created locally.

state: readycreated: 2026-05-13 11:10 UTCvalidation: ready
Published session

Prompt

## Plan Pass

You are planning a fixer patch before any edits happen.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. The original pre-edit snapshot is available at `./source` if you need to inspect it. For interpreter processes, plan from the script/application entrypoint evidence first and include the runtime only as a second investigation target unless the evidence proves a runtime bug.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. Inspect the relevant code, nearby callers, project contribution docs, and local helper/compat APIs, but do not edit files in this pass.

Return a short markdown plan with these exact sections:

## Problem
## Evidence Confidence
## Proposed Subject
## Patch Plan
## Risks
## Validation

Classify `## Evidence Confidence` as exactly one of `reproduced`, `observed`, or `inferred`. Use `inferred` only for a no-patch diagnosis/report plan unless you can name the extra evidence you will collect before editing; inferred source patches are blocked by Fixer because they are not pull-request-ready. For `observed` source-patch plans, plan to say in the final `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. The plan must explain how the proposed code change addresses the observed issue evidence, call out any prior Fixer patch that should be improved or replaced, reject awkward control flow such as avoidable `goto` if there is a cleaner bounded alternative, name any local helper APIs or maintainer conventions the patch should follow, and keep the intended maintainer-facing explanation clear enough that someone unfamiliar with the local complaint wording can still follow the fix. In `## Validation`, name the reproducible configure/build/test entrypoint you will try from the workspace root before any focused leaf compile or smoke check, and include one bounded independent reproduction attempt for the collected failure signal when it is safe and cheap. Do not plan to claim `reproduced` unless that reproduction command or test can actually show the failure.

## Patch Pass

You are working on a bounded fixer proposal.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Produce the smallest reasonable patch for the target repository, keep the change upstreamable, prefer the clearest control flow available, and do not keep avoidable `goto` when a simpler structure would read better. Before introducing new file, process, allocation, locking, networking, or platform APIs, inspect nearby code and project contribution docs for existing helpers or compatibility wrappers and use those local patterns unless you can explain why they do not fit. Validate from a reproducible workspace-root entrypoint before falling back to focused leaf commands; if a build or test cannot run, report the exact command, the exact blocker, and any narrower check you ran instead. During validation, also try one bounded independent reproduction of the collected failure signal when it is safe and cheap, such as a failing test, smoke command, perf/strace comparison, or before/after runtime check. Only use `reproduced` if that command or test actually reproduced the failure; otherwise keep `observed` and report the reproduction blocker. The final explanation must connect the observed issue evidence to the actual code change, not just paraphrase the diff. Write like a maintainer is going to read the patch mail cold: explain the bug in plain language, define subsystem-specific jargon the first time you need it, and make the causal story obvious. Explicitly classify evidence confidence as `reproduced`, `observed`, or `inferred`: `reproduced` means you reproduced the failure locally; `observed` means Fixer has direct crash/log/trace evidence but you did not independently reproduce it; `inferred` means the source patch is not pull-request-ready, so do not leave a source diff unless you first gather stronger observed/reproduced evidence; otherwise return a no-patch diagnosis/report. For any source-changing `observed` patch, say explicitly in `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. If you introduce non-obvious state translation, index remapping, or backend split logic, add a short source comment that explains the invariant being preserved.

Start by explaining the likely root cause from the collected perf, strace, and /proc evidence. If you cannot land a safe patch, leave a diagnosis that is strong enough for an upstream bug report.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. 

Keep the change narrowly scoped and summarize validation clearly.

In every authoring pass, your final response must start with `Subject: <single-line git commit subject>` and then include these markdown sections exactly:

## Commit Message
A short upstream-friendly explanation of what changed and why. Write it in plain language that a maintainer can follow without local complaint context. If you use subsystem jargon, define it immediately.

## Evidence Confidence
Exactly one word: `reproduced`, `observed`, or `inferred`. Use `reproduced` only when you reproduced the failure locally with a command or test, and include that command/test in `## Validation`. Use `observed` when Fixer has direct crash/log/trace evidence but you did not independently reproduce it. If `## Git Add Paths` lists source files for an `observed` patch, `## Issue Connection` must explicitly say the failure was observed by Fixer and not independently reproduced. Use `inferred` for profiler/strace/indirect evidence; inferred responses may be no-patch diagnoses or reports, but inferred source patches are not pull-request-ready until stronger evidence is gathered.

## Issue Connection
Write this as maintainer-facing patch mail, not as local Fixer notes. Cover four things explicitly in readable sentences: the user-visible symptom or the exact collected signal, the code-level cause or the cautious inference from evidence, the specific change you made, and the expected effect. Do not invent a reproducer, command line, crash, or user-visible failure that is not present in the evidence bundle. If the evidence is direct-but-not-reproduced, say it was observed by Fixer and not independently reproduced. If the evidence is indirect and you did not gather stronger evidence, do not leave a source diff; write a no-patch diagnosis/report instead. Include an explicit effect sentence such as `The expected effect is ...`, `This should reduce ...`, or `This prevents ...` for source patches. If the logic is non-obvious in code, mention that you added a short explanatory comment.

## Git Add Paths
List the repo-relative paths that belong in the final patch, one per line. Use `None` only when you intentionally made no source changes. Include intentionally new files, and do not list generated build artifacts.

## Validation
List the checks you ran, or say clearly that you could not run them. Include the independent reproduction command/test and result when `## Evidence Confidence` is `reproduced`; if reproduction was attempted but blocked, name the exact blocker and keep confidence at `observed` or `inferred`.

Before editing, read the plan at `./plan-output.txt` and follow it unless the code proves part of it wrong. If you change course, say so explicitly in the final write-up instead of silently drifting from the plan.

## Review Pass 1

You are reviewing a freshly generated fixer patch.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Review the first patch pass. The original pre-edit snapshot is available at `./source` for diffing.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. The latest author response is at `./patch-output.txt`. Inspect the current code and changed paths like a strict code reviewer. Focus on correctness, regressions, maintainability, awkward control flow such as avoidable `goto`, missing validation, weak or non-gittable commit message text, and explanations that fail to connect the observed issue evidence to the code change. Also review the maintainer experience: the patch mail should be easy to accept upstream, the user-visible bug should be explained in plain language, subsystem-specific jargon should be defined when first used, and any non-obvious state translation or index remapping in code should have a short explanatory comment. Reject patches that omit `## Evidence Confidence`, use anything other than `reproduced`, `observed`, or `inferred`, or sound more certain than that evidence level allows. Reject patches that claim `reproduced` unless `## Validation` names the concrete reproduction command or test and its result. Reject patches that invent a reproducer, command line, crash, or user-visible failure not present in the evidence bundle; indirect profiler or strace evidence may justify a cautious mitigation, but the author must say it is indirect instead of presenting it as a confirmed upstream bug. Reject patches that introduce generic libc/std APIs when nearby code or project docs provide a local compat/helper API for the same job, unless the author explicitly justifies the exception. Reject validation that only reports a leaf object/syntax build when a project-level configure/build/test entrypoint exists and was not attempted; if a full build cannot run, the author must show the exact failed command and blocker.

Do not apply code changes in this pass.

Return a short markdown review report. The first non-empty line must be exactly one of:

RESULT: ok
RESULT: fix-needed

If you choose `RESULT: fix-needed`, add a `## Findings` section with concrete, actionable items.

Response

## Plan Pass

## Problem
Fixer observed `dockerd` sleeping with many futex waits during a short profile. The bundle reports 0.1% CPU, `__schedule` as the hot kernel path, process state `S (sleeping)`, and strace excerpts dominated by unfinished `futex(... FUTEX_WAIT_PRIVATE ...)` plus a few `waitid(P_PIDFD, ...)` calls. The classifier labels this as `socket-churn`, but the embedded excerpts do not show an active socket retry loop or a user-visible failure.

## Evidence Confidence
inferred

## Proposed Subject
No patch: diagnose dockerd sleeping/futex profile as insufficient for an upstream source change

## Patch Plan
Do not edit source in this pass unless stronger evidence is collected first. The current evidence is profiler/strace/process-state data without symbols, logs, a reproducer, or a mapped source frame. A source patch would be speculative.

If additional evidence is collected before editing, target `engine/` first because `/usr/sbin/dockerd` is the application entrypoint. Start at `engine/cmd/dockerd/docker.go`, `engine/cmd/dockerd/daemon.go`, then only inspect runtime/containerd paths such as `engine/libcontainerd/remote/client.go` if traces implicate containerd event processing. Avoid treating Go runtime futex parking as a Moby bug unless goroutine stacks or logs identify a daemon-level loop.

Contribution/style docs found: `engine/CONTRIBUTING.md`, `engine/README.md`, `engine/hack/README.md`, and `engine/TESTING.md`. Conventions to follow for any later patch: use `containerd/log` logging, context cancellation patterns, existing daemon/libcontainerd helpers such as `libcontainerd/queue`, add unit tests for bug fixes, and run `gofmt -s`. No relevant file/process/allocation compatibility helper is needed for the no-patch diagnosis.

No prior Fixer patch appears to exist in the workspace; Debian quilt patches are packaging/build/test related and should not be replaced for this evidence.

## Risks
A patch based only on this bundle could “fix” normal Go scheduler parking or idle daemon behavior. The installed version was `28.5.2+dfsg3-2` while the workspace is `28.5.2+dfsg4-1`, and the raw investigation files referenced in the JSON are not present, so address-to-source mapping and independent trace review are limited.

## Validation
Before any future focused check, try the reproducible workspace-root entrypoint `debian/rules build` or, if full package build is too expensive, document that blocker and run the upstream unit entrypoint from `engine/` with `make test-unit`.

Bounded independent reproduction attempt: start a test `dockerd` only if safe root/containerd/systemd prerequisites are available, using isolated `--data-root`, `--exec-root`, `--pidfile`, and a Unix socket, then sample `strace -f -e futex,waitid` and `/proc/$pid/status`. Do not claim `reproduced` unless that command shows the same problematic signal beyond normal idle futex waits.

## Patch Pass

Subject: No patch: diagnose dockerd futex profile

## Commit Message
No source change was made. The collected data points to `dockerd` threads parked in futex waits while the process was sleeping, but it does not identify a Moby code path, retry loop, or user-visible daemon failure that is safe to patch upstream.

## Evidence Confidence
inferred

## Issue Connection
Fixer collected a short profile of `/usr/sbin/dockerd` showing `__schedule` as the hot kernel path, process state `S (sleeping)`, 0.1% CPU, many unfinished `FUTEX_WAIT_PRIVATE` calls, and a few `waitid(P_PIDFD, ...)` calls. That signal is consistent with Go/runtime goroutines or OS threads being parked, but the bundle does not include symbolized daemon frames, goroutine stacks, logs, or socket syscall excerpts that prove a daemon-level socket churn bug.

The cautious code-level conclusion is that there is no identified Moby source defect yet. I followed the saved plan and did not make a speculative source edit. Contribution docs and local conventions checked earlier point to `engine/CONTRIBUTING.md`, `engine/TESTING.md`, `containerd/log`, context cancellation patterns, and `libcontainerd/queue` if future evidence implicates the daemon/containerd event path, but no relevant helper applies to a no-patch diagnosis.

The expected effect is no behavior change. The useful upstream action is to collect stronger evidence: symbolized `dockerd` frames or goroutine dumps correlated with an active retry loop before proposing a patch.

## Git Add Paths
None

## Validation
`dpkg-checkbuilddeps`: failed because many build dependencies are missing, including `dh-golang`, `golang-any`, and the Go library packages required by Debian packaging.

`timeout 60s debian/rules build`: failed before compilation with `Can't locate Debian/Debhelper/Sequence/golang.pm`, confirming the workspace cannot run the package build entrypoint without `dh-golang`.

Independent reproduction attempt: `timeout --signal=TERM 12s strace -f -e trace=futex,waitid ... /usr/sbin/dockerd ...` with isolated `/tmp` roots and network side effects disabled. It was blocked by sandbox ptrace restrictions: `PTRACE_TRACEME: Operation not permitted`, so the futex signal was not reproduced.

A narrower isolated `dockerd` smoke without strace also failed before startup because the sandbox disallowed creating the Unix listener socket: `setsockopt: operation not permitted`.

`git status --short`: clean; no source changes were left.

## Review Pass 1

RESULT: ok

No findings. The author correctly left no source diff for indirect profiler/strace evidence, used `## Evidence Confidence` as `inferred`, avoided inventing a reproducer or confirmed upstream bug, and reported the project-level build/reproduction blockers clearly. `git diff` is empty and `git status --short` is clean.

diagnosis-only report

report

dockerd likely remains stuck in a socket churn loop. A diagnosis report and patch proposal were created locally.

state: readycreated: 2026-05-13 09:42 UTCvalidation: ready
Published session

Prompt

## Plan Pass

You are planning a fixer patch before any edits happen.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. The original pre-edit snapshot is available at `./source` if you need to inspect it. For interpreter processes, plan from the script/application entrypoint evidence first and include the runtime only as a second investigation target unless the evidence proves a runtime bug.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. Inspect the relevant code, nearby callers, project contribution docs, and local helper/compat APIs, but do not edit files in this pass.

Return a short markdown plan with these exact sections:

## Problem
## Evidence Confidence
## Proposed Subject
## Patch Plan
## Risks
## Validation

Classify `## Evidence Confidence` as exactly one of `reproduced`, `observed`, or `inferred`. Use `inferred` only for a no-patch diagnosis/report plan unless you can name the extra evidence you will collect before editing; inferred source patches are blocked by Fixer because they are not pull-request-ready. For `observed` source-patch plans, plan to say in the final `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. The plan must explain how the proposed code change addresses the observed issue evidence, call out any prior Fixer patch that should be improved or replaced, reject awkward control flow such as avoidable `goto` if there is a cleaner bounded alternative, name any local helper APIs or maintainer conventions the patch should follow, and keep the intended maintainer-facing explanation clear enough that someone unfamiliar with the local complaint wording can still follow the fix. In `## Validation`, name the reproducible configure/build/test entrypoint you will try from the workspace root before any focused leaf compile or smoke check, and include one bounded independent reproduction attempt for the collected failure signal when it is safe and cheap. Do not plan to claim `reproduced` unless that reproduction command or test can actually show the failure.

## Patch Pass

You are working on a bounded fixer proposal.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Produce the smallest reasonable patch for the target repository, keep the change upstreamable, prefer the clearest control flow available, and do not keep avoidable `goto` when a simpler structure would read better. Before introducing new file, process, allocation, locking, networking, or platform APIs, inspect nearby code and project contribution docs for existing helpers or compatibility wrappers and use those local patterns unless you can explain why they do not fit. Validate from a reproducible workspace-root entrypoint before falling back to focused leaf commands; if a build or test cannot run, report the exact command, the exact blocker, and any narrower check you ran instead. During validation, also try one bounded independent reproduction of the collected failure signal when it is safe and cheap, such as a failing test, smoke command, perf/strace comparison, or before/after runtime check. Only use `reproduced` if that command or test actually reproduced the failure; otherwise keep `observed` and report the reproduction blocker. The final explanation must connect the observed issue evidence to the actual code change, not just paraphrase the diff. Write like a maintainer is going to read the patch mail cold: explain the bug in plain language, define subsystem-specific jargon the first time you need it, and make the causal story obvious. Explicitly classify evidence confidence as `reproduced`, `observed`, or `inferred`: `reproduced` means you reproduced the failure locally; `observed` means Fixer has direct crash/log/trace evidence but you did not independently reproduce it; `inferred` means the source patch is not pull-request-ready, so do not leave a source diff unless you first gather stronger observed/reproduced evidence; otherwise return a no-patch diagnosis/report. For any source-changing `observed` patch, say explicitly in `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. If you introduce non-obvious state translation, index remapping, or backend split logic, add a short source comment that explains the invariant being preserved.

Start by explaining the likely root cause from the collected perf, strace, and /proc evidence. If you cannot land a safe patch, leave a diagnosis that is strong enough for an upstream bug report.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. 

Keep the change narrowly scoped and summarize validation clearly.

In every authoring pass, your final response must start with `Subject: <single-line git commit subject>` and then include these markdown sections exactly:

## Commit Message
A short upstream-friendly explanation of what changed and why. Write it in plain language that a maintainer can follow without local complaint context. If you use subsystem jargon, define it immediately.

## Evidence Confidence
Exactly one word: `reproduced`, `observed`, or `inferred`. Use `reproduced` only when you reproduced the failure locally with a command or test, and include that command/test in `## Validation`. Use `observed` when Fixer has direct crash/log/trace evidence but you did not independently reproduce it. If `## Git Add Paths` lists source files for an `observed` patch, `## Issue Connection` must explicitly say the failure was observed by Fixer and not independently reproduced. Use `inferred` for profiler/strace/indirect evidence; inferred responses may be no-patch diagnoses or reports, but inferred source patches are not pull-request-ready until stronger evidence is gathered.

## Issue Connection
Write this as maintainer-facing patch mail, not as local Fixer notes. Cover four things explicitly in readable sentences: the user-visible symptom or the exact collected signal, the code-level cause or the cautious inference from evidence, the specific change you made, and the expected effect. Do not invent a reproducer, command line, crash, or user-visible failure that is not present in the evidence bundle. If the evidence is direct-but-not-reproduced, say it was observed by Fixer and not independently reproduced. If the evidence is indirect and you did not gather stronger evidence, do not leave a source diff; write a no-patch diagnosis/report instead. Include an explicit effect sentence such as `The expected effect is ...`, `This should reduce ...`, or `This prevents ...` for source patches. If the logic is non-obvious in code, mention that you added a short explanatory comment.

## Git Add Paths
List the repo-relative paths that belong in the final patch, one per line. Use `None` only when you intentionally made no source changes. Include intentionally new files, and do not list generated build artifacts.

## Validation
List the checks you ran, or say clearly that you could not run them. Include the independent reproduction command/test and result when `## Evidence Confidence` is `reproduced`; if reproduction was attempted but blocked, name the exact blocker and keep confidence at `observed` or `inferred`.

Before editing, read the plan at `./plan-output.txt` and follow it unless the code proves part of it wrong. If you change course, say so explicitly in the final write-up instead of silently drifting from the plan.

## Review Pass 1

You are reviewing a freshly generated fixer patch.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Review the first patch pass. The original pre-edit snapshot is available at `./source` for diffing.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. The latest author response is at `./patch-output.txt`. Inspect the current code and changed paths like a strict code reviewer. Focus on correctness, regressions, maintainability, awkward control flow such as avoidable `goto`, missing validation, weak or non-gittable commit message text, and explanations that fail to connect the observed issue evidence to the code change. Also review the maintainer experience: the patch mail should be easy to accept upstream, the user-visible bug should be explained in plain language, subsystem-specific jargon should be defined when first used, and any non-obvious state translation or index remapping in code should have a short explanatory comment. Reject patches that omit `## Evidence Confidence`, use anything other than `reproduced`, `observed`, or `inferred`, or sound more certain than that evidence level allows. Reject patches that claim `reproduced` unless `## Validation` names the concrete reproduction command or test and its result. Reject patches that invent a reproducer, command line, crash, or user-visible failure not present in the evidence bundle; indirect profiler or strace evidence may justify a cautious mitigation, but the author must say it is indirect instead of presenting it as a confirmed upstream bug. Reject patches that introduce generic libc/std APIs when nearby code or project docs provide a local compat/helper API for the same job, unless the author explicitly justifies the exception. Reject validation that only reports a leaf object/syntax build when a project-level configure/build/test entrypoint exists and was not attempted; if a full build cannot run, the author must show the exact failed command and blocker.

Do not apply code changes in this pass.

Return a short markdown review report. The first non-empty line must be exactly one of:

RESULT: ok
RESULT: fix-needed

If you choose `RESULT: fix-needed`, add a `## Findings` section with concrete, actionable items.

Response

## Plan Pass

## Problem
`dockerd` was observed by Fixer with 185 threads, mostly sleeping in futex waits, with sampled kernel time under `__schedule`, some `waitid(P_PIDFD, ...)`, `nanosleep`, `epoll_pwait`, and `recvmsg EAGAIN`. The collected backtraces are unsymbolized, CPU was only 0.1%, and the evidence does not identify a Go package, goroutine, API request, container lifecycle path, or reproducible user-visible failure.

## Evidence Confidence
inferred

## Proposed Subject
No source patch yet: collect symbolized daemon/goroutine evidence before editing.

## Patch Plan
Do not edit the upstream engine in this pass. A source patch would be speculative because the current bundle shows an observed daemon state, not a localized bug.

Before any later patch, collect at least one of these extra evidence items:
- A symbolized stack/goroutine dump from the same `dockerd` build, preferably via Moby’s existing goroutine dump support in `engine/pkg/stack` and the daemon debug trap paths.
- PC-to-symbol mapping for the sampled `/usr/sbin/dockerd` addresses using the matching Debian build/debug artifact.
- A focused runtime trace showing which daemon subsystem is creating or retaining the many waiting goroutines/threads.

If that evidence points to a real daemon leak or churn loop, patch the implicated upstream engine package rather than Debian packaging. Follow Moby conventions from `engine/CONTRIBUTING.md` and `engine/TESTING.md`: keep changes under the relevant `daemon`, `cmd/dockerd`, `libcontainerd`, or `libnetwork` package, add a unit test for a bug fix, run `gofmt -s -w`, and avoid new `integration-cli` tests. For logging, use the existing `log.G(ctx)` convention; for goroutine dump/debugging paths, prefer existing `engine/pkg/stack` helpers. No relevant local file-I/O/process wrapper was identified for a concrete patch target yet, though nearby code uses package-specific helpers such as `reexec.Command` where appropriate.

No prior Fixer patch for this issue was found in the workspace. If a later fix touches retry loops, avoid unbounded or awkward `goto`-style control flow; prefer bounded `for`/`select` loops with context cancellation or clear retry limits.

## Risks
The current “socket-churn” label conflicts with the dominant futex/sleeping evidence and low CPU sample. Patching now risks changing unrelated daemon behavior, masking normal idle goroutines, or addressing the Go/runtime/containerd boundary without proof that the fault is in Moby source.

## Validation
For a later source patch, start from the workspace root with the Debian build/test entrypoint: `dpkg-buildpackage -us -uc -b`, or at minimum `debian/rules build` followed by `debian/rules override_dh_auto_test` if the full package build is too expensive.

After localization, run the focused upstream test entrypoint from the configured engine tree: `cd _build/src/github.com/docker/docker && PATH=$GOPATH/bin:$PATH TESTFLAGS='-test.short -vet=off -test.run <targeted-test>' ./hack/test/unit`.

Bounded independent reproduction attempt before claiming reproduction: build `dockerd`, start it in an isolated temporary data root with a test socket for a short timeout, capture goroutine/thread counts and a goroutine dump before and after the suspected operation, and verify the specific futex/thread growth or churn signal changes. Do not claim `reproduced` unless that command actually shows the failure.

## Patch Pass

Subject: Diagnose unsymbolized dockerd scheduler sample

## Commit Message
No source patch was made. The likely root cause cannot be assigned to Moby source from the collected data: `dockerd` was sleeping in futex waits with unsymbolized frames, so the evidence is consistent with Go runtime goroutines parked on locks or waits but does not identify the daemon subsystem that created them.

## Evidence Confidence
inferred

## Issue Connection
Fixer collected a perf/strace/proc sample from `/usr/sbin/dockerd` showing 185 threads, `wchan=futex_do_wait`, 100% of sampled time under kernel `__schedule`, low process CPU at 0.1%, and top syscalls dominated by `futex`, `nanosleep`, `epoll_pwait`, and `waitid(P_PIDFD, ...)`. The backtraces are unsymbolized addresses, and the raw investigation directory referenced by the evidence is not present in this workspace.

The cautious code-level inference is that many Go runtime threads were parked or waiting, but the evidence does not connect that state to a specific Moby package, retry loop, socket path, container lifecycle operation, or leak. I followed the saved plan and did not change course: leaving a source diff here would be an inferred patch, not pull-request-ready.

I checked Moby’s contribution/testing docs and nearby daemon conventions. A later patch should follow `engine/CONTRIBUTING.md` and `engine/TESTING.md`, use `log.G(ctx)` for daemon logging, and prefer existing diagnostic helpers such as `engine/pkg/stack` for goroutine dumps. No relevant local helper was found for a concrete source change because no touched subsystem could be identified. No prior Fixer patch for this issue was found.

The expected effect of this no-patch result is to avoid landing a speculative daemon behavior change until symbolized goroutine/source evidence identifies the actual faulty path.

## Git Add Paths
None

## Validation
`dpkg-buildpackage -us -uc -b` from the workspace root failed before build/test execution. Exact blocker: exit code 3 from `dpkg-checkbuilddeps`, reporting unmet build dependencies including `dh-golang`, `golang-any`, `go-md2man`, and many required `golang-*-dev` packages.

Bounded independent reproduction attempt:
`timeout 8s /usr/sbin/dockerd --debug --data-root "$tmpdir/data" --exec-root "$tmpdir/exec" --pidfile "$tmpdir/dockerd.pid" -H "unix://$tmpdir/docker.sock" --iptables=false --bridge=none --ip-forward=false --ip-masq=false --containerd=/run/containerd/containerd.sock`

Result: did not reproduce the futex/thread signal. It exited with status 1 before startup: `failed to load listeners: can't create unix socket ... setsockopt: operation not permitted`.

Also ran `git diff --check` and `git status --short`; both were clean.

## Review Pass 1

RESULT: ok

The first pass correctly leaves no source diff for indirect, unsymbolized profiler/strace evidence and classifies confidence as `inferred`. The author response includes the required sections, does not invent a reproducer or claim a confirmed upstream bug, and reports the project-level build command plus blocker.

I verified `git diff` is empty and a comparison with the original source snapshot only shows workspace metadata directories (`.agents`, `.codex`). The no-patch diagnosis is appropriate until symbolized goroutine/source evidence identifies a concrete daemon subsystem.

diagnosis-only report

report

dockerd likely remains stuck in a socket churn loop. A diagnosis report and patch proposal were created locally.

state: readycreated: 2026-05-13 09:42 UTCvalidation: ready
Published session

Prompt

## Plan Pass

You are planning a fixer patch before any edits happen.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. The original pre-edit snapshot is available at `./source` if you need to inspect it. For interpreter processes, plan from the script/application entrypoint evidence first and include the runtime only as a second investigation target unless the evidence proves a runtime bug.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. Inspect the relevant code, nearby callers, project contribution docs, and local helper/compat APIs, but do not edit files in this pass.

Return a short markdown plan with these exact sections:

## Problem
## Evidence Confidence
## Proposed Subject
## Patch Plan
## Risks
## Validation

Classify `## Evidence Confidence` as exactly one of `reproduced`, `observed`, or `inferred`. Use `inferred` only for a no-patch diagnosis/report plan unless you can name the extra evidence you will collect before editing; inferred source patches are blocked by Fixer because they are not pull-request-ready. For `observed` source-patch plans, plan to say in the final `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. The plan must explain how the proposed code change addresses the observed issue evidence, call out any prior Fixer patch that should be improved or replaced, reject awkward control flow such as avoidable `goto` if there is a cleaner bounded alternative, name any local helper APIs or maintainer conventions the patch should follow, and keep the intended maintainer-facing explanation clear enough that someone unfamiliar with the local complaint wording can still follow the fix. In `## Validation`, name the reproducible configure/build/test entrypoint you will try from the workspace root before any focused leaf compile or smoke check, and include one bounded independent reproduction attempt for the collected failure signal when it is safe and cheap. Do not plan to claim `reproduced` unless that reproduction command or test can actually show the failure.

## Patch Pass

You are working on a bounded fixer proposal.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Produce the smallest reasonable patch for the target repository, keep the change upstreamable, prefer the clearest control flow available, and do not keep avoidable `goto` when a simpler structure would read better. Before introducing new file, process, allocation, locking, networking, or platform APIs, inspect nearby code and project contribution docs for existing helpers or compatibility wrappers and use those local patterns unless you can explain why they do not fit. Validate from a reproducible workspace-root entrypoint before falling back to focused leaf commands; if a build or test cannot run, report the exact command, the exact blocker, and any narrower check you ran instead. During validation, also try one bounded independent reproduction of the collected failure signal when it is safe and cheap, such as a failing test, smoke command, perf/strace comparison, or before/after runtime check. Only use `reproduced` if that command or test actually reproduced the failure; otherwise keep `observed` and report the reproduction blocker. The final explanation must connect the observed issue evidence to the actual code change, not just paraphrase the diff. Write like a maintainer is going to read the patch mail cold: explain the bug in plain language, define subsystem-specific jargon the first time you need it, and make the causal story obvious. Explicitly classify evidence confidence as `reproduced`, `observed`, or `inferred`: `reproduced` means you reproduced the failure locally; `observed` means Fixer has direct crash/log/trace evidence but you did not independently reproduce it; `inferred` means the source patch is not pull-request-ready, so do not leave a source diff unless you first gather stronger observed/reproduced evidence; otherwise return a no-patch diagnosis/report. For any source-changing `observed` patch, say explicitly in `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. If you introduce non-obvious state translation, index remapping, or backend split logic, add a short source comment that explains the invariant being preserved.

Start by explaining the likely root cause from the collected perf, strace, and /proc evidence. If you cannot land a safe patch, leave a diagnosis that is strong enough for an upstream bug report.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. 

Keep the change narrowly scoped and summarize validation clearly.

In every authoring pass, your final response must start with `Subject: <single-line git commit subject>` and then include these markdown sections exactly:

## Commit Message
A short upstream-friendly explanation of what changed and why. Write it in plain language that a maintainer can follow without local complaint context. If you use subsystem jargon, define it immediately.

## Evidence Confidence
Exactly one word: `reproduced`, `observed`, or `inferred`. Use `reproduced` only when you reproduced the failure locally with a command or test, and include that command/test in `## Validation`. Use `observed` when Fixer has direct crash/log/trace evidence but you did not independently reproduce it. If `## Git Add Paths` lists source files for an `observed` patch, `## Issue Connection` must explicitly say the failure was observed by Fixer and not independently reproduced. Use `inferred` for profiler/strace/indirect evidence; inferred responses may be no-patch diagnoses or reports, but inferred source patches are not pull-request-ready until stronger evidence is gathered.

## Issue Connection
Write this as maintainer-facing patch mail, not as local Fixer notes. Cover four things explicitly in readable sentences: the user-visible symptom or the exact collected signal, the code-level cause or the cautious inference from evidence, the specific change you made, and the expected effect. Do not invent a reproducer, command line, crash, or user-visible failure that is not present in the evidence bundle. If the evidence is direct-but-not-reproduced, say it was observed by Fixer and not independently reproduced. If the evidence is indirect and you did not gather stronger evidence, do not leave a source diff; write a no-patch diagnosis/report instead. Include an explicit effect sentence such as `The expected effect is ...`, `This should reduce ...`, or `This prevents ...` for source patches. If the logic is non-obvious in code, mention that you added a short explanatory comment.

## Git Add Paths
List the repo-relative paths that belong in the final patch, one per line. Use `None` only when you intentionally made no source changes. Include intentionally new files, and do not list generated build artifacts.

## Validation
List the checks you ran, or say clearly that you could not run them. Include the independent reproduction command/test and result when `## Evidence Confidence` is `reproduced`; if reproduction was attempted but blocked, name the exact blocker and keep confidence at `observed` or `inferred`.

Before editing, read the plan at `./plan-output.txt` and follow it unless the code proves part of it wrong. If you change course, say so explicitly in the final write-up instead of silently drifting from the plan.

## Review Pass 1

You are reviewing a freshly generated fixer patch.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Review the first patch pass. The original pre-edit snapshot is available at `./source` for diffing.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. The latest author response is at `./patch-output.txt`. Inspect the current code and changed paths like a strict code reviewer. Focus on correctness, regressions, maintainability, awkward control flow such as avoidable `goto`, missing validation, weak or non-gittable commit message text, and explanations that fail to connect the observed issue evidence to the code change. Also review the maintainer experience: the patch mail should be easy to accept upstream, the user-visible bug should be explained in plain language, subsystem-specific jargon should be defined when first used, and any non-obvious state translation or index remapping in code should have a short explanatory comment. Reject patches that omit `## Evidence Confidence`, use anything other than `reproduced`, `observed`, or `inferred`, or sound more certain than that evidence level allows. Reject patches that claim `reproduced` unless `## Validation` names the concrete reproduction command or test and its result. Reject patches that invent a reproducer, command line, crash, or user-visible failure not present in the evidence bundle; indirect profiler or strace evidence may justify a cautious mitigation, but the author must say it is indirect instead of presenting it as a confirmed upstream bug. Reject patches that introduce generic libc/std APIs when nearby code or project docs provide a local compat/helper API for the same job, unless the author explicitly justifies the exception. Reject validation that only reports a leaf object/syntax build when a project-level configure/build/test entrypoint exists and was not attempted; if a full build cannot run, the author must show the exact failed command and blocker.

Do not apply code changes in this pass.

Return a short markdown review report. The first non-empty line must be exactly one of:

RESULT: ok
RESULT: fix-needed

If you choose `RESULT: fix-needed`, add a `## Findings` section with concrete, actionable items.

Response

## Plan Pass

## Problem
`dockerd` was observed by Fixer with 185 threads, mostly sleeping in futex waits, with sampled kernel time under `__schedule`, some `waitid(P_PIDFD, ...)`, `nanosleep`, `epoll_pwait`, and `recvmsg EAGAIN`. The collected backtraces are unsymbolized, CPU was only 0.1%, and the evidence does not identify a Go package, goroutine, API request, container lifecycle path, or reproducible user-visible failure.

## Evidence Confidence
inferred

## Proposed Subject
No source patch yet: collect symbolized daemon/goroutine evidence before editing.

## Patch Plan
Do not edit the upstream engine in this pass. A source patch would be speculative because the current bundle shows an observed daemon state, not a localized bug.

Before any later patch, collect at least one of these extra evidence items:
- A symbolized stack/goroutine dump from the same `dockerd` build, preferably via Moby’s existing goroutine dump support in `engine/pkg/stack` and the daemon debug trap paths.
- PC-to-symbol mapping for the sampled `/usr/sbin/dockerd` addresses using the matching Debian build/debug artifact.
- A focused runtime trace showing which daemon subsystem is creating or retaining the many waiting goroutines/threads.

If that evidence points to a real daemon leak or churn loop, patch the implicated upstream engine package rather than Debian packaging. Follow Moby conventions from `engine/CONTRIBUTING.md` and `engine/TESTING.md`: keep changes under the relevant `daemon`, `cmd/dockerd`, `libcontainerd`, or `libnetwork` package, add a unit test for a bug fix, run `gofmt -s -w`, and avoid new `integration-cli` tests. For logging, use the existing `log.G(ctx)` convention; for goroutine dump/debugging paths, prefer existing `engine/pkg/stack` helpers. No relevant local file-I/O/process wrapper was identified for a concrete patch target yet, though nearby code uses package-specific helpers such as `reexec.Command` where appropriate.

No prior Fixer patch for this issue was found in the workspace. If a later fix touches retry loops, avoid unbounded or awkward `goto`-style control flow; prefer bounded `for`/`select` loops with context cancellation or clear retry limits.

## Risks
The current “socket-churn” label conflicts with the dominant futex/sleeping evidence and low CPU sample. Patching now risks changing unrelated daemon behavior, masking normal idle goroutines, or addressing the Go/runtime/containerd boundary without proof that the fault is in Moby source.

## Validation
For a later source patch, start from the workspace root with the Debian build/test entrypoint: `dpkg-buildpackage -us -uc -b`, or at minimum `debian/rules build` followed by `debian/rules override_dh_auto_test` if the full package build is too expensive.

After localization, run the focused upstream test entrypoint from the configured engine tree: `cd _build/src/github.com/docker/docker && PATH=$GOPATH/bin:$PATH TESTFLAGS='-test.short -vet=off -test.run <targeted-test>' ./hack/test/unit`.

Bounded independent reproduction attempt before claiming reproduction: build `dockerd`, start it in an isolated temporary data root with a test socket for a short timeout, capture goroutine/thread counts and a goroutine dump before and after the suspected operation, and verify the specific futex/thread growth or churn signal changes. Do not claim `reproduced` unless that command actually shows the failure.

## Patch Pass

Subject: Diagnose unsymbolized dockerd scheduler sample

## Commit Message
No source patch was made. The likely root cause cannot be assigned to Moby source from the collected data: `dockerd` was sleeping in futex waits with unsymbolized frames, so the evidence is consistent with Go runtime goroutines parked on locks or waits but does not identify the daemon subsystem that created them.

## Evidence Confidence
inferred

## Issue Connection
Fixer collected a perf/strace/proc sample from `/usr/sbin/dockerd` showing 185 threads, `wchan=futex_do_wait`, 100% of sampled time under kernel `__schedule`, low process CPU at 0.1%, and top syscalls dominated by `futex`, `nanosleep`, `epoll_pwait`, and `waitid(P_PIDFD, ...)`. The backtraces are unsymbolized addresses, and the raw investigation directory referenced by the evidence is not present in this workspace.

The cautious code-level inference is that many Go runtime threads were parked or waiting, but the evidence does not connect that state to a specific Moby package, retry loop, socket path, container lifecycle operation, or leak. I followed the saved plan and did not change course: leaving a source diff here would be an inferred patch, not pull-request-ready.

I checked Moby’s contribution/testing docs and nearby daemon conventions. A later patch should follow `engine/CONTRIBUTING.md` and `engine/TESTING.md`, use `log.G(ctx)` for daemon logging, and prefer existing diagnostic helpers such as `engine/pkg/stack` for goroutine dumps. No relevant local helper was found for a concrete source change because no touched subsystem could be identified. No prior Fixer patch for this issue was found.

The expected effect of this no-patch result is to avoid landing a speculative daemon behavior change until symbolized goroutine/source evidence identifies the actual faulty path.

## Git Add Paths
None

## Validation
`dpkg-buildpackage -us -uc -b` from the workspace root failed before build/test execution. Exact blocker: exit code 3 from `dpkg-checkbuilddeps`, reporting unmet build dependencies including `dh-golang`, `golang-any`, `go-md2man`, and many required `golang-*-dev` packages.

Bounded independent reproduction attempt:
`timeout 8s /usr/sbin/dockerd --debug --data-root "$tmpdir/data" --exec-root "$tmpdir/exec" --pidfile "$tmpdir/dockerd.pid" -H "unix://$tmpdir/docker.sock" --iptables=false --bridge=none --ip-forward=false --ip-masq=false --containerd=/run/containerd/containerd.sock`

Result: did not reproduce the futex/thread signal. It exited with status 1 before startup: `failed to load listeners: can't create unix socket ... setsockopt: operation not permitted`.

Also ran `git diff --check` and `git status --short`; both were clean.

## Review Pass 1

RESULT: ok

The first pass correctly leaves no source diff for indirect, unsymbolized profiler/strace evidence and classifies confidence as `inferred`. The author response includes the required sections, does not invent a reproducer or claim a confirmed upstream bug, and reports the project-level build command plus blocker.

I verified `git diff` is empty and a comparison with the original source snapshot only shows workspace metadata directories (`.agents`, `.codex`). The no-patch diagnosis is appropriate until symbolized goroutine/source evidence identifies a concrete daemon subsystem.

diagnosis-only report

report

dockerd likely remains stuck in a socket churn loop. A diagnosis report and patch proposal were created locally.

state: readycreated: 2026-05-13 08:22 UTCvalidation: ready
Published session

Prompt

## Plan Pass

You are planning a fixer patch before any edits happen.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. The original pre-edit snapshot is available at `./source` if you need to inspect it. For interpreter processes, plan from the script/application entrypoint evidence first and include the runtime only as a second investigation target unless the evidence proves a runtime bug.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. Inspect the relevant code, nearby callers, project contribution docs, and local helper/compat APIs, but do not edit files in this pass.

Return a short markdown plan with these exact sections:

## Problem
## Evidence Confidence
## Proposed Subject
## Patch Plan
## Risks
## Validation

Classify `## Evidence Confidence` as exactly one of `reproduced`, `observed`, or `inferred`. Use `inferred` only for a no-patch diagnosis/report plan unless you can name the extra evidence you will collect before editing; inferred source patches are blocked by Fixer because they are not pull-request-ready. For `observed` source-patch plans, plan to say in the final `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. The plan must explain how the proposed code change addresses the observed issue evidence, call out any prior Fixer patch that should be improved or replaced, reject awkward control flow such as avoidable `goto` if there is a cleaner bounded alternative, name any local helper APIs or maintainer conventions the patch should follow, and keep the intended maintainer-facing explanation clear enough that someone unfamiliar with the local complaint wording can still follow the fix. In `## Validation`, name the reproducible configure/build/test entrypoint you will try from the workspace root before any focused leaf compile or smoke check, and include one bounded independent reproduction attempt for the collected failure signal when it is safe and cheap. Do not plan to claim `reproduced` unless that reproduction command or test can actually show the failure.

## Patch Pass

You are working on a bounded fixer proposal.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Produce the smallest reasonable patch for the target repository, keep the change upstreamable, prefer the clearest control flow available, and do not keep avoidable `goto` when a simpler structure would read better. Before introducing new file, process, allocation, locking, networking, or platform APIs, inspect nearby code and project contribution docs for existing helpers or compatibility wrappers and use those local patterns unless you can explain why they do not fit. Validate from a reproducible workspace-root entrypoint before falling back to focused leaf commands; if a build or test cannot run, report the exact command, the exact blocker, and any narrower check you ran instead. During validation, also try one bounded independent reproduction of the collected failure signal when it is safe and cheap, such as a failing test, smoke command, perf/strace comparison, or before/after runtime check. Only use `reproduced` if that command or test actually reproduced the failure; otherwise keep `observed` and report the reproduction blocker. The final explanation must connect the observed issue evidence to the actual code change, not just paraphrase the diff. Write like a maintainer is going to read the patch mail cold: explain the bug in plain language, define subsystem-specific jargon the first time you need it, and make the causal story obvious. Explicitly classify evidence confidence as `reproduced`, `observed`, or `inferred`: `reproduced` means you reproduced the failure locally; `observed` means Fixer has direct crash/log/trace evidence but you did not independently reproduce it; `inferred` means the source patch is not pull-request-ready, so do not leave a source diff unless you first gather stronger observed/reproduced evidence; otherwise return a no-patch diagnosis/report. For any source-changing `observed` patch, say explicitly in `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. If you introduce non-obvious state translation, index remapping, or backend split logic, add a short source comment that explains the invariant being preserved.

Start by explaining the likely root cause from the collected perf, strace, and /proc evidence. If you cannot land a safe patch, leave a diagnosis that is strong enough for an upstream bug report.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. 

Keep the change narrowly scoped and summarize validation clearly.

In every authoring pass, your final response must start with `Subject: <single-line git commit subject>` and then include these markdown sections exactly:

## Commit Message
A short upstream-friendly explanation of what changed and why. Write it in plain language that a maintainer can follow without local complaint context. If you use subsystem jargon, define it immediately.

## Evidence Confidence
Exactly one word: `reproduced`, `observed`, or `inferred`. Use `reproduced` only when you reproduced the failure locally with a command or test, and include that command/test in `## Validation`. Use `observed` when Fixer has direct crash/log/trace evidence but you did not independently reproduce it. If `## Git Add Paths` lists source files for an `observed` patch, `## Issue Connection` must explicitly say the failure was observed by Fixer and not independently reproduced. Use `inferred` for profiler/strace/indirect evidence; inferred responses may be no-patch diagnoses or reports, but inferred source patches are not pull-request-ready until stronger evidence is gathered.

## Issue Connection
Write this as maintainer-facing patch mail, not as local Fixer notes. Cover four things explicitly in readable sentences: the user-visible symptom or the exact collected signal, the code-level cause or the cautious inference from evidence, the specific change you made, and the expected effect. Do not invent a reproducer, command line, crash, or user-visible failure that is not present in the evidence bundle. If the evidence is direct-but-not-reproduced, say it was observed by Fixer and not independently reproduced. If the evidence is indirect and you did not gather stronger evidence, do not leave a source diff; write a no-patch diagnosis/report instead. Include an explicit effect sentence such as `The expected effect is ...`, `This should reduce ...`, or `This prevents ...` for source patches. If the logic is non-obvious in code, mention that you added a short explanatory comment.

## Git Add Paths
List the repo-relative paths that belong in the final patch, one per line. Use `None` only when you intentionally made no source changes. Include intentionally new files, and do not list generated build artifacts.

## Validation
List the checks you ran, or say clearly that you could not run them. Include the independent reproduction command/test and result when `## Evidence Confidence` is `reproduced`; if reproduction was attempted but blocked, name the exact blocker and keep confidence at `observed` or `inferred`.

Before editing, read the plan at `./plan-output.txt` and follow it unless the code proves part of it wrong. If you change course, say so explicitly in the final write-up instead of silently drifting from the plan.

## Review Pass 1

You are reviewing a freshly generated fixer patch.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Review the first patch pass. The original pre-edit snapshot is available at `./source` for diffing.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. The latest author response is at `./patch-output.txt`. Inspect the current code and changed paths like a strict code reviewer. Focus on correctness, regressions, maintainability, awkward control flow such as avoidable `goto`, missing validation, weak or non-gittable commit message text, and explanations that fail to connect the observed issue evidence to the code change. Also review the maintainer experience: the patch mail should be easy to accept upstream, the user-visible bug should be explained in plain language, subsystem-specific jargon should be defined when first used, and any non-obvious state translation or index remapping in code should have a short explanatory comment. Reject patches that omit `## Evidence Confidence`, use anything other than `reproduced`, `observed`, or `inferred`, or sound more certain than that evidence level allows. Reject patches that claim `reproduced` unless `## Validation` names the concrete reproduction command or test and its result. Reject patches that invent a reproducer, command line, crash, or user-visible failure not present in the evidence bundle; indirect profiler or strace evidence may justify a cautious mitigation, but the author must say it is indirect instead of presenting it as a confirmed upstream bug. Reject patches that introduce generic libc/std APIs when nearby code or project docs provide a local compat/helper API for the same job, unless the author explicitly justifies the exception. Reject validation that only reports a leaf object/syntax build when a project-level configure/build/test entrypoint exists and was not attempted; if a full build cannot run, the author must show the exact failed command and blocker.

Do not apply code changes in this pass.

Return a short markdown review report. The first non-empty line must be exactly one of:

RESULT: ok
RESULT: fix-needed

If you choose `RESULT: fix-needed`, add a `## Findings` section with concrete, actionable items.

Response

## Plan Pass

## Problem

Fixer observed an installed `dockerd` process started as `/usr/sbin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock` with ~185 threads, very low CPU, kernel hot path `__schedule`, and strace excerpts dominated by `FUTEX_WAIT_PRIVATE` plus a few `waitid(P_PIDFD, ...)` calls. The evidence labels this as `socket-churn`, but the embedded syscall excerpts show sleeping/waiting rather than an actionable socket retry loop. Raw artifact paths referenced in `evidence.json` are not present, so there is no symbolic Go stack or fd/socket mapping available.

## Evidence Confidence

inferred

## Proposed Subject

No source patch yet: diagnose the `dockerd` idle/waiting profile before changing upstream Moby code.

## Patch Plan

1. Treat `engine/cmd/dockerd/docker.go` and `engine/cmd/dockerd/daemon.go` as the application entrypoint path, not the Go runtime, unless new evidence proves a runtime issue.
2. Collect the missing decisive evidence before editing: a symbolic goroutine dump using dockerd’s existing SIGUSR1 stack dump trap, plus fd/socket mapping and a short strace that confirms whether there is actual socket churn or only normal futex/pidfd waits.
3. If that evidence identifies a bounded daemon bug, patch the relevant upstream Moby subsystem and add a focused unit test. Likely local conventions/helpers to follow are `github.com/containerd/log` for logging, `github.com/pkg/errors` wrapping style in older daemon/listener code, `github.com/docker/go-connections/sockets` for socket creation, `github.com/coreos/go-systemd/v22/activation` for `fd://` listeners, and `gofmt -s -w`.
4. Do not add speculative backoff, goroutine limits, or runtime futex changes from the current evidence. The current embedded profile is consistent with an idle daemon sleeping in Go/runtime synchronization.
5. No prior Fixer patch is present in the workspace (`git status --short` is clean), so there is no existing Fixer change to improve or replace.
6. Avoid awkward control flow such as avoidable `goto`; if a patch becomes justified, keep it as a small bounded branch or helper matching nearby daemon/listener style.

## Risks

The main risk is misdiagnosing normal idle `dockerd` behavior as a daemon bug. The evidence classifier says socket churn, but the visible syscalls and CPU profile do not prove a retry loop, user-visible failure, or specific source hotspot. A source patch without the extra stack/fd evidence would not be pull-request-ready.

## Validation

Before any focused leaf compile or smoke check, use the project’s documented test entrypoint from the workspace root: `cd engine && make test-unit` where feasible, or the Debian packaging path `debian/rules override_dh_auto_configure` followed by the relevant `override_dh_auto_build`/`override_dh_auto_test` target if validating the packaged source layout.

Bounded independent reproduction attempt: start a local `dockerd` in an isolated temp root/exec-root with `-H fd://` only if systemd-style fd activation can be cheaply simulated, capture a 5-second `strace -f` and SIGUSR1 goroutine dump while idle, and verify whether it reproduces the observed futex/pidfd waiting signal. Do not claim `reproduced` unless that command actually shows the same waiting profile.

## Patch Pass

Subject: No patch: diagnose dockerd idle wait profile

## Commit Message

Likely root cause: the collected perf, strace, and `/proc` evidence points to an idle or blocked Go daemon, not a confirmed socket retry bug. `dockerd` was sleeping with 0.1% CPU, perf was entirely in the kernel scheduler, and the visible strace lines are futex waits plus pidfd waits. I followed the saved plan and left no source diff because the evidence is indirect and does not identify an upstreamable code-level fix.

## Evidence Confidence

inferred

## Issue Connection

The collected signal is a `dockerd` process started with `-H fd:// --containerd=/run/containerd/containerd.sock`, about 185 threads, process state `S (sleeping)`, perf hot path `__schedule`, and strace excerpts dominated by `FUTEX_WAIT_PRIVATE`. Although the evidence bundle labels the loop as `socket-churn`, the embedded excerpts do not show a concrete socket retry loop, error, crash, or user-visible failure.

The cautious code-level inference is that these samples are consistent with normal Go/runtime synchronization or daemon goroutines waiting for work. The missing raw artifacts mean there is no symbolic goroutine dump, fd target list, or complete strace available to connect the sampled wait state to `engine/cmd/dockerd`, `engine/daemon/listeners`, containerd dialing, or another specific subsystem.

I made no source change. A source patch from this evidence would be speculative and not pull-request-ready. The next upstream-useful report should include a SIGUSR1 goroutine dump from dockerd’s existing stack dump trap, fd/socket targets, and a complete short strace/perf sample showing whether there is actual socket churn.

I checked the contribution/testing docs and nearby daemon/listener code. Relevant local conventions/helpers found were `github.com/containerd/log` for logging, `github.com/coreos/go-systemd/v22/activation` for `fd://` socket activation, `github.com/docker/go-connections/sockets` for socket creation, and Moby’s `make test-unit` test entrypoint. No relevant helper was needed because no patch was made.

## Git Add Paths

None

## Validation

`cd engine && make test-unit`  
Blocked before Go tests: the target tried to build/load the `docker-dev` image and failed with `ERROR: mkdir /root/.docker: read-only file system`.

Independent reproduction attempt:  
`timeout 10s strace -f -e trace=futex,waitid -o /tmp/fixer-dockerd-version.strace /usr/sbin/dockerd --version`  
Blocked by sandbox ptrace restrictions: `PTRACE_TRACEME: Operation not permitted` and `ptrace(PTRACE_SEIZE, 6): Operation not permitted`.

Raw evidence check:  
`test -d /var/lib/fixer/investigations/2026-05-06T20-26-06.323932540+00-00-dockerd-b732bcc6a3ff ...` reported the raw investigation directory is missing, so the embedded evidence could not be strengthened locally.

`git status --short` is clean; no patch was left in the workspace.

## Review Pass 1

RESULT: ok

No source diff is present, and the author response correctly treats the profiler/strace evidence as indirect. `## Evidence Confidence` is `inferred`, `## Git Add Paths` is `None`, and the explanation does not invent a crash, reproducer, or confirmed socket bug beyond the bundle.

Validation is acceptable for a no-patch diagnosis: the workspace-level `make test-unit` entrypoint was attempted and the blocker is stated, and the bounded reproduction attempt was blocked by ptrace restrictions. The response also names the relevant local daemon/listener helpers and explains why no helper was used.

diagnosis-only report

report

dockerd likely remains stuck in a socket churn loop. A diagnosis report and patch proposal were created locally.

state: readycreated: 2026-05-13 08:22 UTCvalidation: ready
Published session

Prompt

## Plan Pass

You are planning a fixer patch before any edits happen.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. The original pre-edit snapshot is available at `./source` if you need to inspect it. For interpreter processes, plan from the script/application entrypoint evidence first and include the runtime only as a second investigation target unless the evidence proves a runtime bug.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. Inspect the relevant code, nearby callers, project contribution docs, and local helper/compat APIs, but do not edit files in this pass.

Return a short markdown plan with these exact sections:

## Problem
## Evidence Confidence
## Proposed Subject
## Patch Plan
## Risks
## Validation

Classify `## Evidence Confidence` as exactly one of `reproduced`, `observed`, or `inferred`. Use `inferred` only for a no-patch diagnosis/report plan unless you can name the extra evidence you will collect before editing; inferred source patches are blocked by Fixer because they are not pull-request-ready. For `observed` source-patch plans, plan to say in the final `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. The plan must explain how the proposed code change addresses the observed issue evidence, call out any prior Fixer patch that should be improved or replaced, reject awkward control flow such as avoidable `goto` if there is a cleaner bounded alternative, name any local helper APIs or maintainer conventions the patch should follow, and keep the intended maintainer-facing explanation clear enough that someone unfamiliar with the local complaint wording can still follow the fix. In `## Validation`, name the reproducible configure/build/test entrypoint you will try from the workspace root before any focused leaf compile or smoke check, and include one bounded independent reproduction attempt for the collected failure signal when it is safe and cheap. Do not plan to claim `reproduced` unless that reproduction command or test can actually show the failure.

## Patch Pass

You are working on a bounded fixer proposal.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Produce the smallest reasonable patch for the target repository, keep the change upstreamable, prefer the clearest control flow available, and do not keep avoidable `goto` when a simpler structure would read better. Before introducing new file, process, allocation, locking, networking, or platform APIs, inspect nearby code and project contribution docs for existing helpers or compatibility wrappers and use those local patterns unless you can explain why they do not fit. Validate from a reproducible workspace-root entrypoint before falling back to focused leaf commands; if a build or test cannot run, report the exact command, the exact blocker, and any narrower check you ran instead. During validation, also try one bounded independent reproduction of the collected failure signal when it is safe and cheap, such as a failing test, smoke command, perf/strace comparison, or before/after runtime check. Only use `reproduced` if that command or test actually reproduced the failure; otherwise keep `observed` and report the reproduction blocker. The final explanation must connect the observed issue evidence to the actual code change, not just paraphrase the diff. Write like a maintainer is going to read the patch mail cold: explain the bug in plain language, define subsystem-specific jargon the first time you need it, and make the causal story obvious. Explicitly classify evidence confidence as `reproduced`, `observed`, or `inferred`: `reproduced` means you reproduced the failure locally; `observed` means Fixer has direct crash/log/trace evidence but you did not independently reproduce it; `inferred` means the source patch is not pull-request-ready, so do not leave a source diff unless you first gather stronger observed/reproduced evidence; otherwise return a no-patch diagnosis/report. For any source-changing `observed` patch, say explicitly in `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. If you introduce non-obvious state translation, index remapping, or backend split logic, add a short source comment that explains the invariant being preserved.

Start by explaining the likely root cause from the collected perf, strace, and /proc evidence. If you cannot land a safe patch, leave a diagnosis that is strong enough for an upstream bug report.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. 

Keep the change narrowly scoped and summarize validation clearly.

In every authoring pass, your final response must start with `Subject: <single-line git commit subject>` and then include these markdown sections exactly:

## Commit Message
A short upstream-friendly explanation of what changed and why. Write it in plain language that a maintainer can follow without local complaint context. If you use subsystem jargon, define it immediately.

## Evidence Confidence
Exactly one word: `reproduced`, `observed`, or `inferred`. Use `reproduced` only when you reproduced the failure locally with a command or test, and include that command/test in `## Validation`. Use `observed` when Fixer has direct crash/log/trace evidence but you did not independently reproduce it. If `## Git Add Paths` lists source files for an `observed` patch, `## Issue Connection` must explicitly say the failure was observed by Fixer and not independently reproduced. Use `inferred` for profiler/strace/indirect evidence; inferred responses may be no-patch diagnoses or reports, but inferred source patches are not pull-request-ready until stronger evidence is gathered.

## Issue Connection
Write this as maintainer-facing patch mail, not as local Fixer notes. Cover four things explicitly in readable sentences: the user-visible symptom or the exact collected signal, the code-level cause or the cautious inference from evidence, the specific change you made, and the expected effect. Do not invent a reproducer, command line, crash, or user-visible failure that is not present in the evidence bundle. If the evidence is direct-but-not-reproduced, say it was observed by Fixer and not independently reproduced. If the evidence is indirect and you did not gather stronger evidence, do not leave a source diff; write a no-patch diagnosis/report instead. Include an explicit effect sentence such as `The expected effect is ...`, `This should reduce ...`, or `This prevents ...` for source patches. If the logic is non-obvious in code, mention that you added a short explanatory comment.

## Git Add Paths
List the repo-relative paths that belong in the final patch, one per line. Use `None` only when you intentionally made no source changes. Include intentionally new files, and do not list generated build artifacts.

## Validation
List the checks you ran, or say clearly that you could not run them. Include the independent reproduction command/test and result when `## Evidence Confidence` is `reproduced`; if reproduction was attempted but blocked, name the exact blocker and keep confidence at `observed` or `inferred`.

Before editing, read the plan at `./plan-output.txt` and follow it unless the code proves part of it wrong. If you change course, say so explicitly in the final write-up instead of silently drifting from the plan.

## Review Pass 1

You are reviewing a freshly generated fixer patch.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Review the first patch pass. The original pre-edit snapshot is available at `./source` for diffing.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. The latest author response is at `./patch-output.txt`. Inspect the current code and changed paths like a strict code reviewer. Focus on correctness, regressions, maintainability, awkward control flow such as avoidable `goto`, missing validation, weak or non-gittable commit message text, and explanations that fail to connect the observed issue evidence to the code change. Also review the maintainer experience: the patch mail should be easy to accept upstream, the user-visible bug should be explained in plain language, subsystem-specific jargon should be defined when first used, and any non-obvious state translation or index remapping in code should have a short explanatory comment. Reject patches that omit `## Evidence Confidence`, use anything other than `reproduced`, `observed`, or `inferred`, or sound more certain than that evidence level allows. Reject patches that claim `reproduced` unless `## Validation` names the concrete reproduction command or test and its result. Reject patches that invent a reproducer, command line, crash, or user-visible failure not present in the evidence bundle; indirect profiler or strace evidence may justify a cautious mitigation, but the author must say it is indirect instead of presenting it as a confirmed upstream bug. Reject patches that introduce generic libc/std APIs when nearby code or project docs provide a local compat/helper API for the same job, unless the author explicitly justifies the exception. Reject validation that only reports a leaf object/syntax build when a project-level configure/build/test entrypoint exists and was not attempted; if a full build cannot run, the author must show the exact failed command and blocker.

Do not apply code changes in this pass.

Return a short markdown review report. The first non-empty line must be exactly one of:

RESULT: ok
RESULT: fix-needed

If you choose `RESULT: fix-needed`, add a `## Findings` section with concrete, actionable items.

Response

## Plan Pass

## Problem

Fixer observed an installed `dockerd` process started as `/usr/sbin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock` with ~185 threads, very low CPU, kernel hot path `__schedule`, and strace excerpts dominated by `FUTEX_WAIT_PRIVATE` plus a few `waitid(P_PIDFD, ...)` calls. The evidence labels this as `socket-churn`, but the embedded syscall excerpts show sleeping/waiting rather than an actionable socket retry loop. Raw artifact paths referenced in `evidence.json` are not present, so there is no symbolic Go stack or fd/socket mapping available.

## Evidence Confidence

inferred

## Proposed Subject

No source patch yet: diagnose the `dockerd` idle/waiting profile before changing upstream Moby code.

## Patch Plan

1. Treat `engine/cmd/dockerd/docker.go` and `engine/cmd/dockerd/daemon.go` as the application entrypoint path, not the Go runtime, unless new evidence proves a runtime issue.
2. Collect the missing decisive evidence before editing: a symbolic goroutine dump using dockerd’s existing SIGUSR1 stack dump trap, plus fd/socket mapping and a short strace that confirms whether there is actual socket churn or only normal futex/pidfd waits.
3. If that evidence identifies a bounded daemon bug, patch the relevant upstream Moby subsystem and add a focused unit test. Likely local conventions/helpers to follow are `github.com/containerd/log` for logging, `github.com/pkg/errors` wrapping style in older daemon/listener code, `github.com/docker/go-connections/sockets` for socket creation, `github.com/coreos/go-systemd/v22/activation` for `fd://` listeners, and `gofmt -s -w`.
4. Do not add speculative backoff, goroutine limits, or runtime futex changes from the current evidence. The current embedded profile is consistent with an idle daemon sleeping in Go/runtime synchronization.
5. No prior Fixer patch is present in the workspace (`git status --short` is clean), so there is no existing Fixer change to improve or replace.
6. Avoid awkward control flow such as avoidable `goto`; if a patch becomes justified, keep it as a small bounded branch or helper matching nearby daemon/listener style.

## Risks

The main risk is misdiagnosing normal idle `dockerd` behavior as a daemon bug. The evidence classifier says socket churn, but the visible syscalls and CPU profile do not prove a retry loop, user-visible failure, or specific source hotspot. A source patch without the extra stack/fd evidence would not be pull-request-ready.

## Validation

Before any focused leaf compile or smoke check, use the project’s documented test entrypoint from the workspace root: `cd engine && make test-unit` where feasible, or the Debian packaging path `debian/rules override_dh_auto_configure` followed by the relevant `override_dh_auto_build`/`override_dh_auto_test` target if validating the packaged source layout.

Bounded independent reproduction attempt: start a local `dockerd` in an isolated temp root/exec-root with `-H fd://` only if systemd-style fd activation can be cheaply simulated, capture a 5-second `strace -f` and SIGUSR1 goroutine dump while idle, and verify whether it reproduces the observed futex/pidfd waiting signal. Do not claim `reproduced` unless that command actually shows the same waiting profile.

## Patch Pass

Subject: No patch: diagnose dockerd idle wait profile

## Commit Message

Likely root cause: the collected perf, strace, and `/proc` evidence points to an idle or blocked Go daemon, not a confirmed socket retry bug. `dockerd` was sleeping with 0.1% CPU, perf was entirely in the kernel scheduler, and the visible strace lines are futex waits plus pidfd waits. I followed the saved plan and left no source diff because the evidence is indirect and does not identify an upstreamable code-level fix.

## Evidence Confidence

inferred

## Issue Connection

The collected signal is a `dockerd` process started with `-H fd:// --containerd=/run/containerd/containerd.sock`, about 185 threads, process state `S (sleeping)`, perf hot path `__schedule`, and strace excerpts dominated by `FUTEX_WAIT_PRIVATE`. Although the evidence bundle labels the loop as `socket-churn`, the embedded excerpts do not show a concrete socket retry loop, error, crash, or user-visible failure.

The cautious code-level inference is that these samples are consistent with normal Go/runtime synchronization or daemon goroutines waiting for work. The missing raw artifacts mean there is no symbolic goroutine dump, fd target list, or complete strace available to connect the sampled wait state to `engine/cmd/dockerd`, `engine/daemon/listeners`, containerd dialing, or another specific subsystem.

I made no source change. A source patch from this evidence would be speculative and not pull-request-ready. The next upstream-useful report should include a SIGUSR1 goroutine dump from dockerd’s existing stack dump trap, fd/socket targets, and a complete short strace/perf sample showing whether there is actual socket churn.

I checked the contribution/testing docs and nearby daemon/listener code. Relevant local conventions/helpers found were `github.com/containerd/log` for logging, `github.com/coreos/go-systemd/v22/activation` for `fd://` socket activation, `github.com/docker/go-connections/sockets` for socket creation, and Moby’s `make test-unit` test entrypoint. No relevant helper was needed because no patch was made.

## Git Add Paths

None

## Validation

`cd engine && make test-unit`  
Blocked before Go tests: the target tried to build/load the `docker-dev` image and failed with `ERROR: mkdir /root/.docker: read-only file system`.

Independent reproduction attempt:  
`timeout 10s strace -f -e trace=futex,waitid -o /tmp/fixer-dockerd-version.strace /usr/sbin/dockerd --version`  
Blocked by sandbox ptrace restrictions: `PTRACE_TRACEME: Operation not permitted` and `ptrace(PTRACE_SEIZE, 6): Operation not permitted`.

Raw evidence check:  
`test -d /var/lib/fixer/investigations/2026-05-06T20-26-06.323932540+00-00-dockerd-b732bcc6a3ff ...` reported the raw investigation directory is missing, so the embedded evidence could not be strengthened locally.

`git status --short` is clean; no patch was left in the workspace.

## Review Pass 1

RESULT: ok

No source diff is present, and the author response correctly treats the profiler/strace evidence as indirect. `## Evidence Confidence` is `inferred`, `## Git Add Paths` is `None`, and the explanation does not invent a crash, reproducer, or confirmed socket bug beyond the bundle.

Validation is acceptable for a no-patch diagnosis: the workspace-level `make test-unit` entrypoint was attempted and the blocker is stated, and the bounded reproduction attempt was blocked by ptrace restrictions. The response also names the relevant local daemon/listener helpers and explains why no helper was used.

diagnosis-only report

report

dockerd likely remains stuck in a socket churn loop. A diagnosis report and patch proposal were created locally.

state: readycreated: 2026-05-13 06:56 UTCvalidation: ready
Published session

Prompt

## Plan Pass

You are planning a fixer patch before any edits happen.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. The original pre-edit snapshot is available at `./source` if you need to inspect it. For interpreter processes, plan from the script/application entrypoint evidence first and include the runtime only as a second investigation target unless the evidence proves a runtime bug.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. Inspect the relevant code, nearby callers, project contribution docs, and local helper/compat APIs, but do not edit files in this pass.

Return a short markdown plan with these exact sections:

## Problem
## Evidence Confidence
## Proposed Subject
## Patch Plan
## Risks
## Validation

Classify `## Evidence Confidence` as exactly one of `reproduced`, `observed`, or `inferred`. Use `inferred` only for a no-patch diagnosis/report plan unless you can name the extra evidence you will collect before editing; inferred source patches are blocked by Fixer because they are not pull-request-ready. For `observed` source-patch plans, plan to say in the final `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. The plan must explain how the proposed code change addresses the observed issue evidence, call out any prior Fixer patch that should be improved or replaced, reject awkward control flow such as avoidable `goto` if there is a cleaner bounded alternative, name any local helper APIs or maintainer conventions the patch should follow, and keep the intended maintainer-facing explanation clear enough that someone unfamiliar with the local complaint wording can still follow the fix. In `## Validation`, name the reproducible configure/build/test entrypoint you will try from the workspace root before any focused leaf compile or smoke check, and include one bounded independent reproduction attempt for the collected failure signal when it is safe and cheap. Do not plan to claim `reproduced` unless that reproduction command or test can actually show the failure.

## Patch Pass

You are working on a bounded fixer proposal.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Produce the smallest reasonable patch for the target repository, keep the change upstreamable, prefer the clearest control flow available, and do not keep avoidable `goto` when a simpler structure would read better. Before introducing new file, process, allocation, locking, networking, or platform APIs, inspect nearby code and project contribution docs for existing helpers or compatibility wrappers and use those local patterns unless you can explain why they do not fit. Validate from a reproducible workspace-root entrypoint before falling back to focused leaf commands; if a build or test cannot run, report the exact command, the exact blocker, and any narrower check you ran instead. During validation, also try one bounded independent reproduction of the collected failure signal when it is safe and cheap, such as a failing test, smoke command, perf/strace comparison, or before/after runtime check. Only use `reproduced` if that command or test actually reproduced the failure; otherwise keep `observed` and report the reproduction blocker. The final explanation must connect the observed issue evidence to the actual code change, not just paraphrase the diff. Write like a maintainer is going to read the patch mail cold: explain the bug in plain language, define subsystem-specific jargon the first time you need it, and make the causal story obvious. Explicitly classify evidence confidence as `reproduced`, `observed`, or `inferred`: `reproduced` means you reproduced the failure locally; `observed` means Fixer has direct crash/log/trace evidence but you did not independently reproduce it; `inferred` means the source patch is not pull-request-ready, so do not leave a source diff unless you first gather stronger observed/reproduced evidence; otherwise return a no-patch diagnosis/report. For any source-changing `observed` patch, say explicitly in `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. If you introduce non-obvious state translation, index remapping, or backend split logic, add a short source comment that explains the invariant being preserved.

Start by explaining the likely root cause from the collected perf, strace, and /proc evidence. If you cannot land a safe patch, leave a diagnosis that is strong enough for an upstream bug report.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. 

Keep the change narrowly scoped and summarize validation clearly.

In every authoring pass, your final response must start with `Subject: <single-line git commit subject>` and then include these markdown sections exactly:

## Commit Message
A short upstream-friendly explanation of what changed and why. Write it in plain language that a maintainer can follow without local complaint context. If you use subsystem jargon, define it immediately.

## Evidence Confidence
Exactly one word: `reproduced`, `observed`, or `inferred`. Use `reproduced` only when you reproduced the failure locally with a command or test, and include that command/test in `## Validation`. Use `observed` when Fixer has direct crash/log/trace evidence but you did not independently reproduce it. If `## Git Add Paths` lists source files for an `observed` patch, `## Issue Connection` must explicitly say the failure was observed by Fixer and not independently reproduced. Use `inferred` for profiler/strace/indirect evidence; inferred responses may be no-patch diagnoses or reports, but inferred source patches are not pull-request-ready until stronger evidence is gathered.

## Issue Connection
Write this as maintainer-facing patch mail, not as local Fixer notes. Cover four things explicitly in readable sentences: the user-visible symptom or the exact collected signal, the code-level cause or the cautious inference from evidence, the specific change you made, and the expected effect. Do not invent a reproducer, command line, crash, or user-visible failure that is not present in the evidence bundle. If the evidence is direct-but-not-reproduced, say it was observed by Fixer and not independently reproduced. If the evidence is indirect and you did not gather stronger evidence, do not leave a source diff; write a no-patch diagnosis/report instead. Include an explicit effect sentence such as `The expected effect is ...`, `This should reduce ...`, or `This prevents ...` for source patches. If the logic is non-obvious in code, mention that you added a short explanatory comment.

## Git Add Paths
List the repo-relative paths that belong in the final patch, one per line. Use `None` only when you intentionally made no source changes. Include intentionally new files, and do not list generated build artifacts.

## Validation
List the checks you ran, or say clearly that you could not run them. Include the independent reproduction command/test and result when `## Evidence Confidence` is `reproduced`; if reproduction was attempted but blocked, name the exact blocker and keep confidence at `observed` or `inferred`.

Before editing, read the plan at `./plan-output.txt` and follow it unless the code proves part of it wrong. If you change course, say so explicitly in the final write-up instead of silently drifting from the plan.

## Review Pass 1

You are reviewing a freshly generated fixer patch.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Review the first patch pass. The original pre-edit snapshot is available at `./source` for diffing.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. The latest author response is at `./patch-output.txt`. Inspect the current code and changed paths like a strict code reviewer. Focus on correctness, regressions, maintainability, awkward control flow such as avoidable `goto`, missing validation, weak or non-gittable commit message text, and explanations that fail to connect the observed issue evidence to the code change. Also review the maintainer experience: the patch mail should be easy to accept upstream, the user-visible bug should be explained in plain language, subsystem-specific jargon should be defined when first used, and any non-obvious state translation or index remapping in code should have a short explanatory comment. Reject patches that omit `## Evidence Confidence`, use anything other than `reproduced`, `observed`, or `inferred`, or sound more certain than that evidence level allows. Reject patches that claim `reproduced` unless `## Validation` names the concrete reproduction command or test and its result. Reject patches that invent a reproducer, command line, crash, or user-visible failure not present in the evidence bundle; indirect profiler or strace evidence may justify a cautious mitigation, but the author must say it is indirect instead of presenting it as a confirmed upstream bug. Reject patches that introduce generic libc/std APIs when nearby code or project docs provide a local compat/helper API for the same job, unless the author explicitly justifies the exception. Reject validation that only reports a leaf object/syntax build when a project-level configure/build/test entrypoint exists and was not attempted; if a full build cannot run, the author must show the exact failed command and blocker.

Do not apply code changes in this pass.

Return a short markdown review report. The first non-empty line must be exactly one of:

RESULT: ok
RESULT: fix-needed

If you choose `RESULT: fix-needed`, add a `## Findings` section with concrete, actionable items.

Response

## Plan Pass

## Problem
Fixer observed `dockerd` with 185 threads mostly sleeping in futex waits; the embedded strace excerpt shows futex, nanosleep, epoll, waitid, and a few nonblocking `recvmsg`/`EAGAIN` calls. The bundle labels this as likely socket churn, but CPU was only 0.1% and symbols are stripped, so the evidence does not identify a concrete `dockerd` source defect.

## Evidence Confidence
inferred

## Proposed Subject
No source patch: request stronger dockerd churn evidence

## Patch Plan
Do not edit source in this pass. Prepare a no-patch diagnosis/report because the available evidence is indirect profiler/strace output, the raw artifact files are absent from the workspace, and the backtrace contains unresolved addresses only.

Before any future source patch, collect stronger evidence: symbolized goroutine or native stacks from the same `dockerd` build, full strace with fd targets, and ideally a bounded before/after reproducer showing socket retry churn. The first code targets would be the `dockerd` entrypoint and daemon listener/containerd paths: `engine/cmd/dockerd/docker.go`, `engine/cmd/dockerd/daemon.go`, `engine/daemon/listeners/listeners_linux.go`, and `engine/daemon/daemon.go`.

Follow Moby conventions from `engine/CONTRIBUTING.md`/`engine/TESTING.md`: Go changes require focused unit tests and `gofmt -s`. Relevant local helpers/conventions found include `containerd/log` via `log.G(ctx)`, listener setup through `daemon/listeners.Init`, socket creation through `github.com/docker/go-connections/sockets`, systemd activation through `activation.Listeners`, runtime path lookup through `homedir.GetRuntimeDir`, and managed containerd startup through `libcontainerd/supervisor.Start`. No awkward `goto`-style control flow should be introduced; if a later patch is justified, use bounded returns and existing helper APIs.

No prior Fixer patch was present to improve or replace; only existing Debian quilt patches are applied.

## Risks
A source patch now would likely be speculative. The observed process was sleeping rather than consuming significant CPU, and unresolved addresses prevent mapping the futex waits to daemon code versus Go runtime, gRPC/containerd internals, plugin waiters, or ordinary idle goroutines. Patching listener, containerd, or retry logic without stronger evidence risks changing daemon startup or socket activation behavior for no confirmed bug.

## Validation
Primary reproducible workspace-root entrypoint to try before focused checks: `DEB_BUILD_OPTIONS=nocheck dpkg-buildpackage -us -uc -b`, or `debian/rules build` if a full package build is too expensive.

Focused checks after any future source change: from `engine`, run `go test` for the touched package, for example `go test ./cmd/dockerd ./daemon/listeners`, then run `gofmt -s -w` on changed Go files.

Bounded independent reproduction attempt: only if safe on the test host, run a short, isolated `dockerd` under `timeout` with temporary `--data-root`, `--exec-root`, a temporary Unix host socket, and a known containerd socket, while collecting `strace -f -e trace=futex,nanosleep,epoll_pwait,recvmsg`. Do not claim reproduction unless this actually shows the same futex/socket-churn signal.

## Patch Pass

Subject: No source patch for inferred dockerd churn

## Commit Message
No source changes were made. The collected perf, strace, and `/proc` evidence points to an idle or waiting `dockerd` process with many threads blocked in futex waits, but it does not identify a specific daemon bug or a safe upstream code change.

## Evidence Confidence
inferred

## Issue Connection
Fixer collected a short profile of `/usr/sbin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock` showing `__schedule` as the hot kernel path, `dockerd` in `S (sleeping)`, `wchan` at `futex_do_wait`, 185 threads, and strace excerpts dominated by futex waits with some `nanosleep`, `epoll_pwait`, `waitid`, and nonblocking `recvmsg`/`EAGAIN`.

The likely root cause from the available evidence is not a confirmed busy loop in Moby code. It is a cautious inference that the daemon had many goroutines or runtime threads blocked on Go/runtime synchronization, gRPC/containerd waits, plugin/process waits, or normal listener activity. The process CPU was only 0.1%, the backtrace addresses were unsymbolized, and the raw strace, fd-target, and gdb files referenced by the bundle were not present in the workspace, so the trace cannot be tied to a concrete source location.

I followed the saved plan and did not change course: no source patch is left because an inferred source patch would be speculative and not pull-request-ready. A useful upstream report should first collect symbolized goroutine/native stacks for the same build, full fd-target data, and a bounded reproduction or before/after trace that maps the churn to a daemon subsystem.

Local conventions checked: `engine/CONTRIBUTING.md` and `engine/TESTING.md` require focused tests and `gofmt -s` for Go changes. Relevant daemon helpers found include `containerd/log` via `log.G(ctx)`, listener setup through `daemon/listeners.Init`, socket creation through `github.com/docker/go-connections/sockets`, systemd activation through `activation.Listeners`, runtime path lookup through `homedir.GetRuntimeDir`, and managed containerd startup through `libcontainerd/supervisor.Start`.

## Git Add Paths
None

## Validation
`timeout 120s env DEB_BUILD_OPTIONS=nocheck dpkg-buildpackage -us -uc -b` from the workspace root failed before building because Debian build dependencies are not installed, starting with `dh-golang`, `golang-any`, `go-md2man`, and many Go library packages.

Independent reproduction attempt: `timeout 10s strace -f -e trace=futex,nanosleep,epoll_pwait,recvmsg /usr/sbin/dockerd --validate --config-file <tempfile>` could not run because ptrace is blocked: `PTRACE_TRACEME: Operation not permitted` and `ptrace(PTRACE_SEIZE, 7): Operation not permitted`.

Fallback smoke check: `timeout 10s /usr/sbin/dockerd --validate --config-file <tempfile>` completed with `configuration OK`. This does not reproduce the collected futex/socket-churn signal because it does not run the long-lived daemon path.

## Review Pass 1

RESULT: ok

No source changes are present in the workspace, and the author response correctly treats the evidence as `inferred` rather than leaving a speculative source patch.

The response includes the required sections, uses a valid evidence confidence value, avoids inventing a reproducer, reports the project-level build attempt and exact dependency blocker, and explains why the perf/strace evidence is insufficient to tie the futex waits to a concrete Moby code defect. It also names relevant Moby conventions and daemon helper APIs (`log.G`, `listeners.Init`, `go-connections/sockets`, `activation.Listeners`, `homedir.GetRuntimeDir`, and `supervisor.Start`).

diagnosis-only report

report

dockerd likely remains stuck in a socket churn loop. A diagnosis report and patch proposal were created locally.

state: readycreated: 2026-05-13 06:56 UTCvalidation: ready
Published session

Prompt

## Plan Pass

You are planning a fixer patch before any edits happen.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. The original pre-edit snapshot is available at `./source` if you need to inspect it. For interpreter processes, plan from the script/application entrypoint evidence first and include the runtime only as a second investigation target unless the evidence proves a runtime bug.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. Inspect the relevant code, nearby callers, project contribution docs, and local helper/compat APIs, but do not edit files in this pass.

Return a short markdown plan with these exact sections:

## Problem
## Evidence Confidence
## Proposed Subject
## Patch Plan
## Risks
## Validation

Classify `## Evidence Confidence` as exactly one of `reproduced`, `observed`, or `inferred`. Use `inferred` only for a no-patch diagnosis/report plan unless you can name the extra evidence you will collect before editing; inferred source patches are blocked by Fixer because they are not pull-request-ready. For `observed` source-patch plans, plan to say in the final `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. The plan must explain how the proposed code change addresses the observed issue evidence, call out any prior Fixer patch that should be improved or replaced, reject awkward control flow such as avoidable `goto` if there is a cleaner bounded alternative, name any local helper APIs or maintainer conventions the patch should follow, and keep the intended maintainer-facing explanation clear enough that someone unfamiliar with the local complaint wording can still follow the fix. In `## Validation`, name the reproducible configure/build/test entrypoint you will try from the workspace root before any focused leaf compile or smoke check, and include one bounded independent reproduction attempt for the collected failure signal when it is safe and cheap. Do not plan to claim `reproduced` unless that reproduction command or test can actually show the failure.

## Patch Pass

You are working on a bounded fixer proposal.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Produce the smallest reasonable patch for the target repository, keep the change upstreamable, prefer the clearest control flow available, and do not keep avoidable `goto` when a simpler structure would read better. Before introducing new file, process, allocation, locking, networking, or platform APIs, inspect nearby code and project contribution docs for existing helpers or compatibility wrappers and use those local patterns unless you can explain why they do not fit. Validate from a reproducible workspace-root entrypoint before falling back to focused leaf commands; if a build or test cannot run, report the exact command, the exact blocker, and any narrower check you ran instead. During validation, also try one bounded independent reproduction of the collected failure signal when it is safe and cheap, such as a failing test, smoke command, perf/strace comparison, or before/after runtime check. Only use `reproduced` if that command or test actually reproduced the failure; otherwise keep `observed` and report the reproduction blocker. The final explanation must connect the observed issue evidence to the actual code change, not just paraphrase the diff. Write like a maintainer is going to read the patch mail cold: explain the bug in plain language, define subsystem-specific jargon the first time you need it, and make the causal story obvious. Explicitly classify evidence confidence as `reproduced`, `observed`, or `inferred`: `reproduced` means you reproduced the failure locally; `observed` means Fixer has direct crash/log/trace evidence but you did not independently reproduce it; `inferred` means the source patch is not pull-request-ready, so do not leave a source diff unless you first gather stronger observed/reproduced evidence; otherwise return a no-patch diagnosis/report. For any source-changing `observed` patch, say explicitly in `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. If you introduce non-obvious state translation, index remapping, or backend split logic, add a short source comment that explains the invariant being preserved.

Start by explaining the likely root cause from the collected perf, strace, and /proc evidence. If you cannot land a safe patch, leave a diagnosis that is strong enough for an upstream bug report.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. 

Keep the change narrowly scoped and summarize validation clearly.

In every authoring pass, your final response must start with `Subject: <single-line git commit subject>` and then include these markdown sections exactly:

## Commit Message
A short upstream-friendly explanation of what changed and why. Write it in plain language that a maintainer can follow without local complaint context. If you use subsystem jargon, define it immediately.

## Evidence Confidence
Exactly one word: `reproduced`, `observed`, or `inferred`. Use `reproduced` only when you reproduced the failure locally with a command or test, and include that command/test in `## Validation`. Use `observed` when Fixer has direct crash/log/trace evidence but you did not independently reproduce it. If `## Git Add Paths` lists source files for an `observed` patch, `## Issue Connection` must explicitly say the failure was observed by Fixer and not independently reproduced. Use `inferred` for profiler/strace/indirect evidence; inferred responses may be no-patch diagnoses or reports, but inferred source patches are not pull-request-ready until stronger evidence is gathered.

## Issue Connection
Write this as maintainer-facing patch mail, not as local Fixer notes. Cover four things explicitly in readable sentences: the user-visible symptom or the exact collected signal, the code-level cause or the cautious inference from evidence, the specific change you made, and the expected effect. Do not invent a reproducer, command line, crash, or user-visible failure that is not present in the evidence bundle. If the evidence is direct-but-not-reproduced, say it was observed by Fixer and not independently reproduced. If the evidence is indirect and you did not gather stronger evidence, do not leave a source diff; write a no-patch diagnosis/report instead. Include an explicit effect sentence such as `The expected effect is ...`, `This should reduce ...`, or `This prevents ...` for source patches. If the logic is non-obvious in code, mention that you added a short explanatory comment.

## Git Add Paths
List the repo-relative paths that belong in the final patch, one per line. Use `None` only when you intentionally made no source changes. Include intentionally new files, and do not list generated build artifacts.

## Validation
List the checks you ran, or say clearly that you could not run them. Include the independent reproduction command/test and result when `## Evidence Confidence` is `reproduced`; if reproduction was attempted but blocked, name the exact blocker and keep confidence at `observed` or `inferred`.

Before editing, read the plan at `./plan-output.txt` and follow it unless the code proves part of it wrong. If you change course, say so explicitly in the final write-up instead of silently drifting from the plan.

## Review Pass 1

You are reviewing a freshly generated fixer patch.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Review the first patch pass. The original pre-edit snapshot is available at `./source` for diffing.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. The latest author response is at `./patch-output.txt`. Inspect the current code and changed paths like a strict code reviewer. Focus on correctness, regressions, maintainability, awkward control flow such as avoidable `goto`, missing validation, weak or non-gittable commit message text, and explanations that fail to connect the observed issue evidence to the code change. Also review the maintainer experience: the patch mail should be easy to accept upstream, the user-visible bug should be explained in plain language, subsystem-specific jargon should be defined when first used, and any non-obvious state translation or index remapping in code should have a short explanatory comment. Reject patches that omit `## Evidence Confidence`, use anything other than `reproduced`, `observed`, or `inferred`, or sound more certain than that evidence level allows. Reject patches that claim `reproduced` unless `## Validation` names the concrete reproduction command or test and its result. Reject patches that invent a reproducer, command line, crash, or user-visible failure not present in the evidence bundle; indirect profiler or strace evidence may justify a cautious mitigation, but the author must say it is indirect instead of presenting it as a confirmed upstream bug. Reject patches that introduce generic libc/std APIs when nearby code or project docs provide a local compat/helper API for the same job, unless the author explicitly justifies the exception. Reject validation that only reports a leaf object/syntax build when a project-level configure/build/test entrypoint exists and was not attempted; if a full build cannot run, the author must show the exact failed command and blocker.

Do not apply code changes in this pass.

Return a short markdown review report. The first non-empty line must be exactly one of:

RESULT: ok
RESULT: fix-needed

If you choose `RESULT: fix-needed`, add a `## Findings` section with concrete, actionable items.

Response

## Plan Pass

## Problem
Fixer observed `dockerd` with 185 threads mostly sleeping in futex waits; the embedded strace excerpt shows futex, nanosleep, epoll, waitid, and a few nonblocking `recvmsg`/`EAGAIN` calls. The bundle labels this as likely socket churn, but CPU was only 0.1% and symbols are stripped, so the evidence does not identify a concrete `dockerd` source defect.

## Evidence Confidence
inferred

## Proposed Subject
No source patch: request stronger dockerd churn evidence

## Patch Plan
Do not edit source in this pass. Prepare a no-patch diagnosis/report because the available evidence is indirect profiler/strace output, the raw artifact files are absent from the workspace, and the backtrace contains unresolved addresses only.

Before any future source patch, collect stronger evidence: symbolized goroutine or native stacks from the same `dockerd` build, full strace with fd targets, and ideally a bounded before/after reproducer showing socket retry churn. The first code targets would be the `dockerd` entrypoint and daemon listener/containerd paths: `engine/cmd/dockerd/docker.go`, `engine/cmd/dockerd/daemon.go`, `engine/daemon/listeners/listeners_linux.go`, and `engine/daemon/daemon.go`.

Follow Moby conventions from `engine/CONTRIBUTING.md`/`engine/TESTING.md`: Go changes require focused unit tests and `gofmt -s`. Relevant local helpers/conventions found include `containerd/log` via `log.G(ctx)`, listener setup through `daemon/listeners.Init`, socket creation through `github.com/docker/go-connections/sockets`, systemd activation through `activation.Listeners`, runtime path lookup through `homedir.GetRuntimeDir`, and managed containerd startup through `libcontainerd/supervisor.Start`. No awkward `goto`-style control flow should be introduced; if a later patch is justified, use bounded returns and existing helper APIs.

No prior Fixer patch was present to improve or replace; only existing Debian quilt patches are applied.

## Risks
A source patch now would likely be speculative. The observed process was sleeping rather than consuming significant CPU, and unresolved addresses prevent mapping the futex waits to daemon code versus Go runtime, gRPC/containerd internals, plugin waiters, or ordinary idle goroutines. Patching listener, containerd, or retry logic without stronger evidence risks changing daemon startup or socket activation behavior for no confirmed bug.

## Validation
Primary reproducible workspace-root entrypoint to try before focused checks: `DEB_BUILD_OPTIONS=nocheck dpkg-buildpackage -us -uc -b`, or `debian/rules build` if a full package build is too expensive.

Focused checks after any future source change: from `engine`, run `go test` for the touched package, for example `go test ./cmd/dockerd ./daemon/listeners`, then run `gofmt -s -w` on changed Go files.

Bounded independent reproduction attempt: only if safe on the test host, run a short, isolated `dockerd` under `timeout` with temporary `--data-root`, `--exec-root`, a temporary Unix host socket, and a known containerd socket, while collecting `strace -f -e trace=futex,nanosleep,epoll_pwait,recvmsg`. Do not claim reproduction unless this actually shows the same futex/socket-churn signal.

## Patch Pass

Subject: No source patch for inferred dockerd churn

## Commit Message
No source changes were made. The collected perf, strace, and `/proc` evidence points to an idle or waiting `dockerd` process with many threads blocked in futex waits, but it does not identify a specific daemon bug or a safe upstream code change.

## Evidence Confidence
inferred

## Issue Connection
Fixer collected a short profile of `/usr/sbin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock` showing `__schedule` as the hot kernel path, `dockerd` in `S (sleeping)`, `wchan` at `futex_do_wait`, 185 threads, and strace excerpts dominated by futex waits with some `nanosleep`, `epoll_pwait`, `waitid`, and nonblocking `recvmsg`/`EAGAIN`.

The likely root cause from the available evidence is not a confirmed busy loop in Moby code. It is a cautious inference that the daemon had many goroutines or runtime threads blocked on Go/runtime synchronization, gRPC/containerd waits, plugin/process waits, or normal listener activity. The process CPU was only 0.1%, the backtrace addresses were unsymbolized, and the raw strace, fd-target, and gdb files referenced by the bundle were not present in the workspace, so the trace cannot be tied to a concrete source location.

I followed the saved plan and did not change course: no source patch is left because an inferred source patch would be speculative and not pull-request-ready. A useful upstream report should first collect symbolized goroutine/native stacks for the same build, full fd-target data, and a bounded reproduction or before/after trace that maps the churn to a daemon subsystem.

Local conventions checked: `engine/CONTRIBUTING.md` and `engine/TESTING.md` require focused tests and `gofmt -s` for Go changes. Relevant daemon helpers found include `containerd/log` via `log.G(ctx)`, listener setup through `daemon/listeners.Init`, socket creation through `github.com/docker/go-connections/sockets`, systemd activation through `activation.Listeners`, runtime path lookup through `homedir.GetRuntimeDir`, and managed containerd startup through `libcontainerd/supervisor.Start`.

## Git Add Paths
None

## Validation
`timeout 120s env DEB_BUILD_OPTIONS=nocheck dpkg-buildpackage -us -uc -b` from the workspace root failed before building because Debian build dependencies are not installed, starting with `dh-golang`, `golang-any`, `go-md2man`, and many Go library packages.

Independent reproduction attempt: `timeout 10s strace -f -e trace=futex,nanosleep,epoll_pwait,recvmsg /usr/sbin/dockerd --validate --config-file <tempfile>` could not run because ptrace is blocked: `PTRACE_TRACEME: Operation not permitted` and `ptrace(PTRACE_SEIZE, 7): Operation not permitted`.

Fallback smoke check: `timeout 10s /usr/sbin/dockerd --validate --config-file <tempfile>` completed with `configuration OK`. This does not reproduce the collected futex/socket-churn signal because it does not run the long-lived daemon path.

## Review Pass 1

RESULT: ok

No source changes are present in the workspace, and the author response correctly treats the evidence as `inferred` rather than leaving a speculative source patch.

The response includes the required sections, uses a valid evidence confidence value, avoids inventing a reproducer, reports the project-level build attempt and exact dependency blocker, and explains why the perf/strace evidence is insufficient to tie the futex waits to a concrete Moby code defect. It also names relevant Moby conventions and daemon helper APIs (`log.G`, `listeners.Init`, `go-connections/sockets`, `activation.Listeners`, `homedir.GetRuntimeDir`, and `supervisor.Start`).

diagnosis-only report

report

dockerd likely remains stuck in a socket churn loop. A diagnosis report and patch proposal were created locally.

state: readycreated: 2026-05-13 05:42 UTCvalidation: ready
Published session

Prompt

## Plan Pass

You are planning a fixer patch before any edits happen.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. The original pre-edit snapshot is available at `./source` if you need to inspect it. For interpreter processes, plan from the script/application entrypoint evidence first and include the runtime only as a second investigation target unless the evidence proves a runtime bug.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. Inspect the relevant code, nearby callers, project contribution docs, and local helper/compat APIs, but do not edit files in this pass.

Return a short markdown plan with these exact sections:

## Problem
## Evidence Confidence
## Proposed Subject
## Patch Plan
## Risks
## Validation

Classify `## Evidence Confidence` as exactly one of `reproduced`, `observed`, or `inferred`. Use `inferred` only for a no-patch diagnosis/report plan unless you can name the extra evidence you will collect before editing; inferred source patches are blocked by Fixer because they are not pull-request-ready. For `observed` source-patch plans, plan to say in the final `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. The plan must explain how the proposed code change addresses the observed issue evidence, call out any prior Fixer patch that should be improved or replaced, reject awkward control flow such as avoidable `goto` if there is a cleaner bounded alternative, name any local helper APIs or maintainer conventions the patch should follow, and keep the intended maintainer-facing explanation clear enough that someone unfamiliar with the local complaint wording can still follow the fix. In `## Validation`, name the reproducible configure/build/test entrypoint you will try from the workspace root before any focused leaf compile or smoke check, and include one bounded independent reproduction attempt for the collected failure signal when it is safe and cheap. Do not plan to claim `reproduced` unless that reproduction command or test can actually show the failure.

## Patch Pass

You are working on a bounded fixer proposal.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Produce the smallest reasonable patch for the target repository, keep the change upstreamable, prefer the clearest control flow available, and do not keep avoidable `goto` when a simpler structure would read better. Before introducing new file, process, allocation, locking, networking, or platform APIs, inspect nearby code and project contribution docs for existing helpers or compatibility wrappers and use those local patterns unless you can explain why they do not fit. Validate from a reproducible workspace-root entrypoint before falling back to focused leaf commands; if a build or test cannot run, report the exact command, the exact blocker, and any narrower check you ran instead. During validation, also try one bounded independent reproduction of the collected failure signal when it is safe and cheap, such as a failing test, smoke command, perf/strace comparison, or before/after runtime check. Only use `reproduced` if that command or test actually reproduced the failure; otherwise keep `observed` and report the reproduction blocker. The final explanation must connect the observed issue evidence to the actual code change, not just paraphrase the diff. Write like a maintainer is going to read the patch mail cold: explain the bug in plain language, define subsystem-specific jargon the first time you need it, and make the causal story obvious. Explicitly classify evidence confidence as `reproduced`, `observed`, or `inferred`: `reproduced` means you reproduced the failure locally; `observed` means Fixer has direct crash/log/trace evidence but you did not independently reproduce it; `inferred` means the source patch is not pull-request-ready, so do not leave a source diff unless you first gather stronger observed/reproduced evidence; otherwise return a no-patch diagnosis/report. For any source-changing `observed` patch, say explicitly in `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. If you introduce non-obvious state translation, index remapping, or backend split logic, add a short source comment that explains the invariant being preserved.

Start by explaining the likely root cause from the collected perf, strace, and /proc evidence. If you cannot land a safe patch, leave a diagnosis that is strong enough for an upstream bug report.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. 

Keep the change narrowly scoped and summarize validation clearly.

In every authoring pass, your final response must start with `Subject: <single-line git commit subject>` and then include these markdown sections exactly:

## Commit Message
A short upstream-friendly explanation of what changed and why. Write it in plain language that a maintainer can follow without local complaint context. If you use subsystem jargon, define it immediately.

## Evidence Confidence
Exactly one word: `reproduced`, `observed`, or `inferred`. Use `reproduced` only when you reproduced the failure locally with a command or test, and include that command/test in `## Validation`. Use `observed` when Fixer has direct crash/log/trace evidence but you did not independently reproduce it. If `## Git Add Paths` lists source files for an `observed` patch, `## Issue Connection` must explicitly say the failure was observed by Fixer and not independently reproduced. Use `inferred` for profiler/strace/indirect evidence; inferred responses may be no-patch diagnoses or reports, but inferred source patches are not pull-request-ready until stronger evidence is gathered.

## Issue Connection
Write this as maintainer-facing patch mail, not as local Fixer notes. Cover four things explicitly in readable sentences: the user-visible symptom or the exact collected signal, the code-level cause or the cautious inference from evidence, the specific change you made, and the expected effect. Do not invent a reproducer, command line, crash, or user-visible failure that is not present in the evidence bundle. If the evidence is direct-but-not-reproduced, say it was observed by Fixer and not independently reproduced. If the evidence is indirect and you did not gather stronger evidence, do not leave a source diff; write a no-patch diagnosis/report instead. Include an explicit effect sentence such as `The expected effect is ...`, `This should reduce ...`, or `This prevents ...` for source patches. If the logic is non-obvious in code, mention that you added a short explanatory comment.

## Git Add Paths
List the repo-relative paths that belong in the final patch, one per line. Use `None` only when you intentionally made no source changes. Include intentionally new files, and do not list generated build artifacts.

## Validation
List the checks you ran, or say clearly that you could not run them. Include the independent reproduction command/test and result when `## Evidence Confidence` is `reproduced`; if reproduction was attempted but blocked, name the exact blocker and keep confidence at `observed` or `inferred`.

Before editing, read the plan at `./plan-output.txt` and follow it unless the code proves part of it wrong. If you change course, say so explicitly in the final write-up instead of silently drifting from the plan.

## Review Pass 1

You are reviewing a freshly generated fixer patch.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Review the first patch pass. The original pre-edit snapshot is available at `./source` for diffing.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. The latest author response is at `./patch-output.txt`. Inspect the current code and changed paths like a strict code reviewer. Focus on correctness, regressions, maintainability, awkward control flow such as avoidable `goto`, missing validation, weak or non-gittable commit message text, and explanations that fail to connect the observed issue evidence to the code change. Also review the maintainer experience: the patch mail should be easy to accept upstream, the user-visible bug should be explained in plain language, subsystem-specific jargon should be defined when first used, and any non-obvious state translation or index remapping in code should have a short explanatory comment. Reject patches that omit `## Evidence Confidence`, use anything other than `reproduced`, `observed`, or `inferred`, or sound more certain than that evidence level allows. Reject patches that claim `reproduced` unless `## Validation` names the concrete reproduction command or test and its result. Reject patches that invent a reproducer, command line, crash, or user-visible failure not present in the evidence bundle; indirect profiler or strace evidence may justify a cautious mitigation, but the author must say it is indirect instead of presenting it as a confirmed upstream bug. Reject patches that introduce generic libc/std APIs when nearby code or project docs provide a local compat/helper API for the same job, unless the author explicitly justifies the exception. Reject validation that only reports a leaf object/syntax build when a project-level configure/build/test entrypoint exists and was not attempted; if a full build cannot run, the author must show the exact failed command and blocker.

Do not apply code changes in this pass.

Return a short markdown review report. The first non-empty line must be exactly one of:

RESULT: ok
RESULT: fix-needed

If you choose `RESULT: fix-needed`, add a `## Findings` section with concrete, actionable items.

Response

## Plan Pass

## Problem

Fixer sampled `dockerd` running as `/usr/sbin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock` and reported a 3s profile dominated by kernel `__schedule` and futex waits, with process state `S (sleeping)` and only 0.1% CPU. The bundle labels this as “socket-churn”, but the visible syscall sequence is futex/futex/futex and the Go backtraces are unsymbolized, so there is no source-level failing loop, listener, or containerd call path to patch yet.

## Evidence Confidence

inferred

## Proposed Subject

No source patch in this pass. Prepare a diagnosis/report and require one extra evidence collection step before editing: symbolized Go stacks or a goroutine dump from the sampled `dockerd`, plus the missing raw `strace.log`/fd listing referenced by `evidence.json`.

## Patch Plan

- Do not invent a user-visible dockerd failure from this profiler-only evidence.
- Treat `engine/cmd/dockerd` as the entrypoint first; only investigate containerd runtime behavior second, because the evidence command line points to dockerd and does not prove a runtime bug.
- If later evidence identifies `fd://` listener setup, follow the existing path: `loadListeners` in `engine/cmd/dockerd/daemon.go` calls `daemon/listeners.Init`, which uses `coreos/go-systemd/activation` helpers for socket activation. Keep logging through `containerd/log`’s `log.G(ctx)` convention.
- If a patch becomes justified, keep it upstream-style in `engine/`, not Debian-local, add a focused unit test near `engine/cmd/dockerd/daemon_linux_test.go` or `engine/daemon/listeners`, and use simple bounded returns/guards rather than avoidable `goto`.
- No prior Fixer patch was found in the worktree or Debian patch series, so there is nothing to improve or replace.

## Risks

The current evidence may describe normal idle dockerd behavior: many sleeping goroutines blocked on futexes, low CPU, and no captured user-space symbols. A speculative source change would be unlikely to pass upstream review because it cannot be tied to a concrete bug or reproducer.

## Validation

Before any focused check, run from the workspace root: `cd engine && make test-unit`.

If later evidence justifies a listener-path patch, follow with `cd engine && go test ./cmd/dockerd ./daemon/listeners`. For a bounded independent reproduction attempt, run an unmodified local dockerd/listener activation unit test such as `cd engine && go test ./cmd/dockerd -run TestLoadListenerNoAddr -count=1`; only claim reproduction if that command or a collected goroutine/strace signal actually shows the failure.

## Patch Pass

Subject: No patch: dockerd futex profile lacks source-level fault

## Commit Message
No source change was made. The collected signal points to `dockerd` sleeping in futex waits with very low CPU, but it does not identify a failing Go call path or a reproducible user-visible bug.

## Evidence Confidence
inferred

## Issue Connection
Fixer collected a `dockerd` profile for `/usr/sbin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock` showing process state `S (sleeping)`, 0.1% CPU, kernel `__schedule`, and a dominant futex wait sequence. Although the bundle labels the sample as “socket-churn,” the visible `/proc`, perf, and strace excerpts look more like idle or blocked goroutines than a proven tight socket retry loop.

The cautious code-level inference is that more evidence is needed before changing upstream Moby. The backtraces in the bundle are unsymbolized, and the raw `strace.log`, fd target list, and gdb backtrace paths referenced by `evidence.json` are not present in this workspace. I inspected the relevant `dockerd` entrypoint and listener path: `loadListeners` in `engine/cmd/dockerd/daemon.go` delegates `fd://` handling to `daemon/listeners.Init`, which uses `coreos/go-systemd/activation`; logging follows `containerd/log` via `log.G(ctx)`. No local helper or convention pointed to a safe targeted mitigation.

I followed the saved plan and did not leave a speculative source diff. The expected effect is that this proposal remains upstreamable as a diagnosis/report instead of presenting normal-looking futex wait evidence as a confirmed daemon bug.

## Git Add Paths
None

## Validation
Checked contribution and test guidance in `engine/CONTRIBUTING.md` and `engine/TESTING.md`, plus nearby listener code in `engine/cmd/dockerd/daemon.go`, `engine/cmd/dockerd/daemon_linux_test.go`, and `engine/daemon/listeners/listeners_linux.go`.

Validation attempted from the documented entrypoint:
`cd engine && timeout 120s make test-unit`
Blocked because the Makefile invoked Docker Buildx, which failed with `ERROR: mkdir /root/.docker: read-only file system`.

Independent reproduction attempt:
`cd engine && go test ./cmd/dockerd -run TestLoadListenerNoAddr -count=1`
Blocked by missing writable Go cache/home and dependency resolution. Retried with:
`cd engine && env HOME=/tmp GOCACHE=/tmp/go-cache GOFLAGS=-mod=vendor go test ./cmd/dockerd -run TestLoadListenerNoAddr -count=1`
That was blocked by inconsistent vendoring between `go.mod` and `vendor/modules.txt` in this Debian source snapshot.

Also checked for stronger local evidence: the raw `strace.log`, `fd-targets.txt`, and `gdb-bt.txt` referenced by the evidence bundle are missing, and there is no built executable `dockerd` in the workspace to symbolize or smoke-test.

## Review Pass 1

RESULT: ok

No source diff is present, and the author correctly treated the profiler-only futex evidence as insufficient for an upstream patch. The response includes `## Evidence Confidence` with valid value `inferred`, does not invent a reproducer or confirmed user-visible bug, names the relevant local listener/helper path (`loadListeners`, `daemon/listeners.Init`, `coreos/go-systemd/activation`, `log.G(ctx)`), and reports the project-level validation attempt with the exact blocker before narrower checks.

Residual workspace-only items such as `engine/bundles` appear ignored/untracked and are not listed for git add.

diagnosis-only report

report

dockerd likely remains stuck in a socket churn loop. A diagnosis report and patch proposal were created locally.

state: readycreated: 2026-05-13 05:42 UTCvalidation: ready
Published session

Prompt

## Plan Pass

You are planning a fixer patch before any edits happen.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. The original pre-edit snapshot is available at `./source` if you need to inspect it. For interpreter processes, plan from the script/application entrypoint evidence first and include the runtime only as a second investigation target unless the evidence proves a runtime bug.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. Inspect the relevant code, nearby callers, project contribution docs, and local helper/compat APIs, but do not edit files in this pass.

Return a short markdown plan with these exact sections:

## Problem
## Evidence Confidence
## Proposed Subject
## Patch Plan
## Risks
## Validation

Classify `## Evidence Confidence` as exactly one of `reproduced`, `observed`, or `inferred`. Use `inferred` only for a no-patch diagnosis/report plan unless you can name the extra evidence you will collect before editing; inferred source patches are blocked by Fixer because they are not pull-request-ready. For `observed` source-patch plans, plan to say in the final `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. The plan must explain how the proposed code change addresses the observed issue evidence, call out any prior Fixer patch that should be improved or replaced, reject awkward control flow such as avoidable `goto` if there is a cleaner bounded alternative, name any local helper APIs or maintainer conventions the patch should follow, and keep the intended maintainer-facing explanation clear enough that someone unfamiliar with the local complaint wording can still follow the fix. In `## Validation`, name the reproducible configure/build/test entrypoint you will try from the workspace root before any focused leaf compile or smoke check, and include one bounded independent reproduction attempt for the collected failure signal when it is safe and cheap. Do not plan to claim `reproduced` unless that reproduction command or test can actually show the failure.

## Patch Pass

You are working on a bounded fixer proposal.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Produce the smallest reasonable patch for the target repository, keep the change upstreamable, prefer the clearest control flow available, and do not keep avoidable `goto` when a simpler structure would read better. Before introducing new file, process, allocation, locking, networking, or platform APIs, inspect nearby code and project contribution docs for existing helpers or compatibility wrappers and use those local patterns unless you can explain why they do not fit. Validate from a reproducible workspace-root entrypoint before falling back to focused leaf commands; if a build or test cannot run, report the exact command, the exact blocker, and any narrower check you ran instead. During validation, also try one bounded independent reproduction of the collected failure signal when it is safe and cheap, such as a failing test, smoke command, perf/strace comparison, or before/after runtime check. Only use `reproduced` if that command or test actually reproduced the failure; otherwise keep `observed` and report the reproduction blocker. The final explanation must connect the observed issue evidence to the actual code change, not just paraphrase the diff. Write like a maintainer is going to read the patch mail cold: explain the bug in plain language, define subsystem-specific jargon the first time you need it, and make the causal story obvious. Explicitly classify evidence confidence as `reproduced`, `observed`, or `inferred`: `reproduced` means you reproduced the failure locally; `observed` means Fixer has direct crash/log/trace evidence but you did not independently reproduce it; `inferred` means the source patch is not pull-request-ready, so do not leave a source diff unless you first gather stronger observed/reproduced evidence; otherwise return a no-patch diagnosis/report. For any source-changing `observed` patch, say explicitly in `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. If you introduce non-obvious state translation, index remapping, or backend split logic, add a short source comment that explains the invariant being preserved.

Start by explaining the likely root cause from the collected perf, strace, and /proc evidence. If you cannot land a safe patch, leave a diagnosis that is strong enough for an upstream bug report.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. 

Keep the change narrowly scoped and summarize validation clearly.

In every authoring pass, your final response must start with `Subject: <single-line git commit subject>` and then include these markdown sections exactly:

## Commit Message
A short upstream-friendly explanation of what changed and why. Write it in plain language that a maintainer can follow without local complaint context. If you use subsystem jargon, define it immediately.

## Evidence Confidence
Exactly one word: `reproduced`, `observed`, or `inferred`. Use `reproduced` only when you reproduced the failure locally with a command or test, and include that command/test in `## Validation`. Use `observed` when Fixer has direct crash/log/trace evidence but you did not independently reproduce it. If `## Git Add Paths` lists source files for an `observed` patch, `## Issue Connection` must explicitly say the failure was observed by Fixer and not independently reproduced. Use `inferred` for profiler/strace/indirect evidence; inferred responses may be no-patch diagnoses or reports, but inferred source patches are not pull-request-ready until stronger evidence is gathered.

## Issue Connection
Write this as maintainer-facing patch mail, not as local Fixer notes. Cover four things explicitly in readable sentences: the user-visible symptom or the exact collected signal, the code-level cause or the cautious inference from evidence, the specific change you made, and the expected effect. Do not invent a reproducer, command line, crash, or user-visible failure that is not present in the evidence bundle. If the evidence is direct-but-not-reproduced, say it was observed by Fixer and not independently reproduced. If the evidence is indirect and you did not gather stronger evidence, do not leave a source diff; write a no-patch diagnosis/report instead. Include an explicit effect sentence such as `The expected effect is ...`, `This should reduce ...`, or `This prevents ...` for source patches. If the logic is non-obvious in code, mention that you added a short explanatory comment.

## Git Add Paths
List the repo-relative paths that belong in the final patch, one per line. Use `None` only when you intentionally made no source changes. Include intentionally new files, and do not list generated build artifacts.

## Validation
List the checks you ran, or say clearly that you could not run them. Include the independent reproduction command/test and result when `## Evidence Confidence` is `reproduced`; if reproduction was attempted but blocked, name the exact blocker and keep confidence at `observed` or `inferred`.

Before editing, read the plan at `./plan-output.txt` and follow it unless the code proves part of it wrong. If you change course, say so explicitly in the final write-up instead of silently drifting from the plan.

## Review Pass 1

You are reviewing a freshly generated fixer patch.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Review the first patch pass. The original pre-edit snapshot is available at `./source` for diffing.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. The latest author response is at `./patch-output.txt`. Inspect the current code and changed paths like a strict code reviewer. Focus on correctness, regressions, maintainability, awkward control flow such as avoidable `goto`, missing validation, weak or non-gittable commit message text, and explanations that fail to connect the observed issue evidence to the code change. Also review the maintainer experience: the patch mail should be easy to accept upstream, the user-visible bug should be explained in plain language, subsystem-specific jargon should be defined when first used, and any non-obvious state translation or index remapping in code should have a short explanatory comment. Reject patches that omit `## Evidence Confidence`, use anything other than `reproduced`, `observed`, or `inferred`, or sound more certain than that evidence level allows. Reject patches that claim `reproduced` unless `## Validation` names the concrete reproduction command or test and its result. Reject patches that invent a reproducer, command line, crash, or user-visible failure not present in the evidence bundle; indirect profiler or strace evidence may justify a cautious mitigation, but the author must say it is indirect instead of presenting it as a confirmed upstream bug. Reject patches that introduce generic libc/std APIs when nearby code or project docs provide a local compat/helper API for the same job, unless the author explicitly justifies the exception. Reject validation that only reports a leaf object/syntax build when a project-level configure/build/test entrypoint exists and was not attempted; if a full build cannot run, the author must show the exact failed command and blocker.

Do not apply code changes in this pass.

Return a short markdown review report. The first non-empty line must be exactly one of:

RESULT: ok
RESULT: fix-needed

If you choose `RESULT: fix-needed`, add a `## Findings` section with concrete, actionable items.

Response

## Plan Pass

## Problem

Fixer sampled `dockerd` running as `/usr/sbin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock` and reported a 3s profile dominated by kernel `__schedule` and futex waits, with process state `S (sleeping)` and only 0.1% CPU. The bundle labels this as “socket-churn”, but the visible syscall sequence is futex/futex/futex and the Go backtraces are unsymbolized, so there is no source-level failing loop, listener, or containerd call path to patch yet.

## Evidence Confidence

inferred

## Proposed Subject

No source patch in this pass. Prepare a diagnosis/report and require one extra evidence collection step before editing: symbolized Go stacks or a goroutine dump from the sampled `dockerd`, plus the missing raw `strace.log`/fd listing referenced by `evidence.json`.

## Patch Plan

- Do not invent a user-visible dockerd failure from this profiler-only evidence.
- Treat `engine/cmd/dockerd` as the entrypoint first; only investigate containerd runtime behavior second, because the evidence command line points to dockerd and does not prove a runtime bug.
- If later evidence identifies `fd://` listener setup, follow the existing path: `loadListeners` in `engine/cmd/dockerd/daemon.go` calls `daemon/listeners.Init`, which uses `coreos/go-systemd/activation` helpers for socket activation. Keep logging through `containerd/log`’s `log.G(ctx)` convention.
- If a patch becomes justified, keep it upstream-style in `engine/`, not Debian-local, add a focused unit test near `engine/cmd/dockerd/daemon_linux_test.go` or `engine/daemon/listeners`, and use simple bounded returns/guards rather than avoidable `goto`.
- No prior Fixer patch was found in the worktree or Debian patch series, so there is nothing to improve or replace.

## Risks

The current evidence may describe normal idle dockerd behavior: many sleeping goroutines blocked on futexes, low CPU, and no captured user-space symbols. A speculative source change would be unlikely to pass upstream review because it cannot be tied to a concrete bug or reproducer.

## Validation

Before any focused check, run from the workspace root: `cd engine && make test-unit`.

If later evidence justifies a listener-path patch, follow with `cd engine && go test ./cmd/dockerd ./daemon/listeners`. For a bounded independent reproduction attempt, run an unmodified local dockerd/listener activation unit test such as `cd engine && go test ./cmd/dockerd -run TestLoadListenerNoAddr -count=1`; only claim reproduction if that command or a collected goroutine/strace signal actually shows the failure.

## Patch Pass

Subject: No patch: dockerd futex profile lacks source-level fault

## Commit Message
No source change was made. The collected signal points to `dockerd` sleeping in futex waits with very low CPU, but it does not identify a failing Go call path or a reproducible user-visible bug.

## Evidence Confidence
inferred

## Issue Connection
Fixer collected a `dockerd` profile for `/usr/sbin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock` showing process state `S (sleeping)`, 0.1% CPU, kernel `__schedule`, and a dominant futex wait sequence. Although the bundle labels the sample as “socket-churn,” the visible `/proc`, perf, and strace excerpts look more like idle or blocked goroutines than a proven tight socket retry loop.

The cautious code-level inference is that more evidence is needed before changing upstream Moby. The backtraces in the bundle are unsymbolized, and the raw `strace.log`, fd target list, and gdb backtrace paths referenced by `evidence.json` are not present in this workspace. I inspected the relevant `dockerd` entrypoint and listener path: `loadListeners` in `engine/cmd/dockerd/daemon.go` delegates `fd://` handling to `daemon/listeners.Init`, which uses `coreos/go-systemd/activation`; logging follows `containerd/log` via `log.G(ctx)`. No local helper or convention pointed to a safe targeted mitigation.

I followed the saved plan and did not leave a speculative source diff. The expected effect is that this proposal remains upstreamable as a diagnosis/report instead of presenting normal-looking futex wait evidence as a confirmed daemon bug.

## Git Add Paths
None

## Validation
Checked contribution and test guidance in `engine/CONTRIBUTING.md` and `engine/TESTING.md`, plus nearby listener code in `engine/cmd/dockerd/daemon.go`, `engine/cmd/dockerd/daemon_linux_test.go`, and `engine/daemon/listeners/listeners_linux.go`.

Validation attempted from the documented entrypoint:
`cd engine && timeout 120s make test-unit`
Blocked because the Makefile invoked Docker Buildx, which failed with `ERROR: mkdir /root/.docker: read-only file system`.

Independent reproduction attempt:
`cd engine && go test ./cmd/dockerd -run TestLoadListenerNoAddr -count=1`
Blocked by missing writable Go cache/home and dependency resolution. Retried with:
`cd engine && env HOME=/tmp GOCACHE=/tmp/go-cache GOFLAGS=-mod=vendor go test ./cmd/dockerd -run TestLoadListenerNoAddr -count=1`
That was blocked by inconsistent vendoring between `go.mod` and `vendor/modules.txt` in this Debian source snapshot.

Also checked for stronger local evidence: the raw `strace.log`, `fd-targets.txt`, and `gdb-bt.txt` referenced by the evidence bundle are missing, and there is no built executable `dockerd` in the workspace to symbolize or smoke-test.

## Review Pass 1

RESULT: ok

No source diff is present, and the author correctly treated the profiler-only futex evidence as insufficient for an upstream patch. The response includes `## Evidence Confidence` with valid value `inferred`, does not invent a reproducer or confirmed user-visible bug, names the relevant local listener/helper path (`loadListeners`, `daemon/listeners.Init`, `coreos/go-systemd/activation`, `log.G(ctx)`), and reports the project-level validation attempt with the exact blocker before narrower checks.

Residual workspace-only items such as `engine/bundles` appear ignored/untracked and are not listed for git add.

diagnosis-only report

report

dockerd likely remains stuck in a socket churn loop. A diagnosis report and patch proposal were created locally.

state: readycreated: 2026-05-13 04:26 UTCvalidation: ready
Published session

Prompt

## Plan Pass

You are planning a fixer patch before any edits happen.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. The original pre-edit snapshot is available at `./source` if you need to inspect it. For interpreter processes, plan from the script/application entrypoint evidence first and include the runtime only as a second investigation target unless the evidence proves a runtime bug.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. Inspect the relevant code, nearby callers, project contribution docs, and local helper/compat APIs, but do not edit files in this pass.

Return a short markdown plan with these exact sections:

## Problem
## Evidence Confidence
## Proposed Subject
## Patch Plan
## Risks
## Validation

Classify `## Evidence Confidence` as exactly one of `reproduced`, `observed`, or `inferred`. Use `inferred` only for a no-patch diagnosis/report plan unless you can name the extra evidence you will collect before editing; inferred source patches are blocked by Fixer because they are not pull-request-ready. For `observed` source-patch plans, plan to say in the final `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. The plan must explain how the proposed code change addresses the observed issue evidence, call out any prior Fixer patch that should be improved or replaced, reject awkward control flow such as avoidable `goto` if there is a cleaner bounded alternative, name any local helper APIs or maintainer conventions the patch should follow, and keep the intended maintainer-facing explanation clear enough that someone unfamiliar with the local complaint wording can still follow the fix. In `## Validation`, name the reproducible configure/build/test entrypoint you will try from the workspace root before any focused leaf compile or smoke check, and include one bounded independent reproduction attempt for the collected failure signal when it is safe and cheap. Do not plan to claim `reproduced` unless that reproduction command or test can actually show the failure.

## Patch Pass

You are working on a bounded fixer proposal.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Produce the smallest reasonable patch for the target repository, keep the change upstreamable, prefer the clearest control flow available, and do not keep avoidable `goto` when a simpler structure would read better. Before introducing new file, process, allocation, locking, networking, or platform APIs, inspect nearby code and project contribution docs for existing helpers or compatibility wrappers and use those local patterns unless you can explain why they do not fit. Validate from a reproducible workspace-root entrypoint before falling back to focused leaf commands; if a build or test cannot run, report the exact command, the exact blocker, and any narrower check you ran instead. During validation, also try one bounded independent reproduction of the collected failure signal when it is safe and cheap, such as a failing test, smoke command, perf/strace comparison, or before/after runtime check. Only use `reproduced` if that command or test actually reproduced the failure; otherwise keep `observed` and report the reproduction blocker. The final explanation must connect the observed issue evidence to the actual code change, not just paraphrase the diff. Write like a maintainer is going to read the patch mail cold: explain the bug in plain language, define subsystem-specific jargon the first time you need it, and make the causal story obvious. Explicitly classify evidence confidence as `reproduced`, `observed`, or `inferred`: `reproduced` means you reproduced the failure locally; `observed` means Fixer has direct crash/log/trace evidence but you did not independently reproduce it; `inferred` means the source patch is not pull-request-ready, so do not leave a source diff unless you first gather stronger observed/reproduced evidence; otherwise return a no-patch diagnosis/report. For any source-changing `observed` patch, say explicitly in `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. If you introduce non-obvious state translation, index remapping, or backend split logic, add a short source comment that explains the invariant being preserved.

Start by explaining the likely root cause from the collected perf, strace, and /proc evidence. If you cannot land a safe patch, leave a diagnosis that is strong enough for an upstream bug report.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. 

Keep the change narrowly scoped and summarize validation clearly.

In every authoring pass, your final response must start with `Subject: <single-line git commit subject>` and then include these markdown sections exactly:

## Commit Message
A short upstream-friendly explanation of what changed and why. Write it in plain language that a maintainer can follow without local complaint context. If you use subsystem jargon, define it immediately.

## Evidence Confidence
Exactly one word: `reproduced`, `observed`, or `inferred`. Use `reproduced` only when you reproduced the failure locally with a command or test, and include that command/test in `## Validation`. Use `observed` when Fixer has direct crash/log/trace evidence but you did not independently reproduce it. If `## Git Add Paths` lists source files for an `observed` patch, `## Issue Connection` must explicitly say the failure was observed by Fixer and not independently reproduced. Use `inferred` for profiler/strace/indirect evidence; inferred responses may be no-patch diagnoses or reports, but inferred source patches are not pull-request-ready until stronger evidence is gathered.

## Issue Connection
Write this as maintainer-facing patch mail, not as local Fixer notes. Cover four things explicitly in readable sentences: the user-visible symptom or the exact collected signal, the code-level cause or the cautious inference from evidence, the specific change you made, and the expected effect. Do not invent a reproducer, command line, crash, or user-visible failure that is not present in the evidence bundle. If the evidence is direct-but-not-reproduced, say it was observed by Fixer and not independently reproduced. If the evidence is indirect and you did not gather stronger evidence, do not leave a source diff; write a no-patch diagnosis/report instead. Include an explicit effect sentence such as `The expected effect is ...`, `This should reduce ...`, or `This prevents ...` for source patches. If the logic is non-obvious in code, mention that you added a short explanatory comment.

## Git Add Paths
List the repo-relative paths that belong in the final patch, one per line. Use `None` only when you intentionally made no source changes. Include intentionally new files, and do not list generated build artifacts.

## Validation
List the checks you ran, or say clearly that you could not run them. Include the independent reproduction command/test and result when `## Evidence Confidence` is `reproduced`; if reproduction was attempted but blocked, name the exact blocker and keep confidence at `observed` or `inferred`.

Before editing, read the plan at `./plan-output.txt` and follow it unless the code proves part of it wrong. If you change course, say so explicitly in the final write-up instead of silently drifting from the plan.

## Review Pass 1

You are reviewing a freshly generated fixer patch.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Review the first patch pass. The original pre-edit snapshot is available at `./source` for diffing.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. The latest author response is at `./patch-output.txt`. Inspect the current code and changed paths like a strict code reviewer. Focus on correctness, regressions, maintainability, awkward control flow such as avoidable `goto`, missing validation, weak or non-gittable commit message text, and explanations that fail to connect the observed issue evidence to the code change. Also review the maintainer experience: the patch mail should be easy to accept upstream, the user-visible bug should be explained in plain language, subsystem-specific jargon should be defined when first used, and any non-obvious state translation or index remapping in code should have a short explanatory comment. Reject patches that omit `## Evidence Confidence`, use anything other than `reproduced`, `observed`, or `inferred`, or sound more certain than that evidence level allows. Reject patches that claim `reproduced` unless `## Validation` names the concrete reproduction command or test and its result. Reject patches that invent a reproducer, command line, crash, or user-visible failure not present in the evidence bundle; indirect profiler or strace evidence may justify a cautious mitigation, but the author must say it is indirect instead of presenting it as a confirmed upstream bug. Reject patches that introduce generic libc/std APIs when nearby code or project docs provide a local compat/helper API for the same job, unless the author explicitly justifies the exception. Reject validation that only reports a leaf object/syntax build when a project-level configure/build/test entrypoint exists and was not attempted; if a full build cannot run, the author must show the exact failed command and blocker.

Do not apply code changes in this pass.

Return a short markdown review report. The first non-empty line must be exactly one of:

RESULT: ok
RESULT: fix-needed

If you choose `RESULT: fix-needed`, add a `## Findings` section with concrete, actionable items.

Response

## Plan Pass

## Problem

Fixer observed `dockerd` started as `/usr/sbin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock` with low CPU, many sleeping threads, futex waits, and an automated `socket-churn` classification. The available evidence is profiler/strace/proc excerpts only; raw strace/fd artifacts referenced in `evidence.json` are not present in this workspace, and the stripped backtrace cannot be mapped to Go symbols.

## Evidence Confidence

inferred

## Proposed Subject

No source patch yet: collect symbolized dockerd socket/futex evidence before editing

## Patch Plan

Do not edit source in this pass. The evidence does not yet identify a source-level defect strongly enough for an upstreamable `docker.io`/Moby patch.

Before any future patch, collect stronger evidence by mapping the hot `dockerd` goroutines to source: obtain a symbolized goroutine dump or rebuild/run an unstripped `dockerd`, then repeat a bounded `strace -f -tt -e trace=futex,network` sample against the same `-H fd:// --containerd=...` startup shape.

If stronger evidence implicates socket activation/API serving, patch in `engine/daemon/listeners` or `engine/cmd/dockerd` following existing conventions: `log.G(ctx)` for logging, `github.com/docker/go-connections/sockets` for socket creation, `homedir.StickRuntimeDirContents` for runtime-dir socket handling, and existing `reexec`-based tests in `engine/cmd/dockerd/daemon_linux_test.go`. Avoid awkward `goto`; use bounded loops/timers like the existing `waitServe` pattern.

No prior Fixer source patch is present in the workspace (`git diff` is empty), so there is nothing to replace yet.

## Risks

A speculative source change could mask normal Go runtime futex parking or normal daemon idle behavior. The excerpt shows the process sleeping with very low CPU, while the `socket-churn` label is automated and not backed by available raw socket syscall details.

A future patch in listener/containerd reconnect paths could affect daemon startup under systemd socket activation, so it needs a focused regression test around `fd://` listener selection and shutdown/retry behavior.

## Validation

Primary workspace-root entrypoint to try after a real patch: `dpkg-buildpackage -us -uc -b`, which exercises the Debian build and the package test hooks from `debian/rules`.

Focused checks after that, if needed: `cd engine && make test-unit TESTDIRS=./cmd/dockerd TESTFLAGS='-run TestLoadListenerNoAddr'` or the equivalent Debian GOPATH test path after `dh_auto_configure`.

Bounded independent reproduction attempt before editing: run a short local `dockerd --validate`/listener-focused test and, only if a safe daemon instance is available, sample it with `timeout 10s strace -f -tt -e trace=futex,network` to see whether the collected futex/socket signal can actually be reproduced. Do not claim `reproduced` unless that command shows the same signal.

## Patch Pass

Subject: no source change for inferred dockerd socket-churn profile

## Commit Message

No patch was made. The collected data shows a sleeping `dockerd` with many futex waits and an automated socket-churn classification, but the available backtrace is stripped and the raw strace/fd artifacts are not present in this workspace. That is not enough to identify an upstream source defect.

## Evidence Confidence

inferred

## Issue Connection

The likely root cause cannot be established from the available evidence. The perf signal points at kernel scheduling, `/proc` shows `dockerd` sleeping with about `0.1%` CPU, and the included strace excerpt shows threads blocked in `FUTEX_WAIT_PRIVATE`. That can describe ordinary parked Go goroutines as well as a real retry loop. The bundle also labels the profile as `socket-churn`, but the raw socket syscall trace needed to connect that label to a Moby code path is unavailable here.

I followed the saved plan and did not change course: no source diff was left because an inferred source patch would not be pull-request-ready. I inspected Moby’s contribution/testing docs and the likely daemon paths. If stronger evidence later implicates listener setup, the relevant local conventions are `engine/daemon/listeners`, `github.com/docker/go-connections/sockets`, systemd activation helpers, `homedir.StickRuntimeDirContents`, `log.G(ctx)`, and the existing `reexec` socket-activation tests.

No code change was made. The expected effect is to avoid shipping a speculative daemon change until a symbolized goroutine dump, unstripped backtrace, or reproducible strace/perf sample ties the futex/socket signal to a specific Moby loop.

## Git Add Paths

None

## Validation

Read `./plan-output.txt` and followed its no-patch recommendation.

Workspace-root build preflight: `dpkg-checkbuilddeps` failed because build dependencies are not installed, starting with `dh-golang`, `golang-any`, `go-md2man`, and many Go `-dev` packages. Because of that blocker and because no source files changed, I did not run `dpkg-buildpackage -us -uc -b`.

Independent reproduction attempt: `ps -C dockerd -o pid=,args=` found no live `dockerd` process to sample. `strace` is installed, but without a safe target PID I could not repeat the futex/network trace. The raw evidence paths for `strace.log` and `fd-targets.txt` also do not exist in this sandbox.

Focused leaf check: `cd engine && go test ./cmd/dockerd -run TestLoadListenerNoAddr -count=1` failed before running tests because module imports are unavailable with lookup disabled by `-mod=readonly`; it also reported `GOCACHE`/`HOME` unset. `git diff --stat` and `git status --short` produced no output, confirming no local source changes.

## Review Pass 1

RESULT: ok

The first pass leaves no source diff, which matches the evidence level. The author response includes `## Evidence Confidence` with valid value `inferred`, avoids claiming a reproduced bug, and does not invent a user-visible failure beyond the profiler/strace evidence.

I found no changed paths in `git status`, `git diff --stat`, or `git diff`. The no-patch diagnosis is consistent with the bundle: stripped backtraces, futex waits, low CPU, and unavailable raw artifacts do not identify a pull-request-ready Moby source defect.

The response also names relevant local conventions for any future daemon/listener patch: `github.com/docker/go-connections/sockets`, systemd activation helpers, `homedir.StickRuntimeDirContents`, `log.G(ctx)`, and existing `reexec` tests. Validation is acceptable for a no-source-change pass: it reports the workspace-root build preflight blocker, the failed bounded reproduction attempt, and the focused test environment blocker.

diagnosis-only report

report

dockerd likely remains stuck in a socket churn loop. A diagnosis report and patch proposal were created locally.

state: readycreated: 2026-05-13 04:26 UTCvalidation: ready
Published session

Prompt

## Plan Pass

You are planning a fixer patch before any edits happen.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. The original pre-edit snapshot is available at `./source` if you need to inspect it. For interpreter processes, plan from the script/application entrypoint evidence first and include the runtime only as a second investigation target unless the evidence proves a runtime bug.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. Inspect the relevant code, nearby callers, project contribution docs, and local helper/compat APIs, but do not edit files in this pass.

Return a short markdown plan with these exact sections:

## Problem
## Evidence Confidence
## Proposed Subject
## Patch Plan
## Risks
## Validation

Classify `## Evidence Confidence` as exactly one of `reproduced`, `observed`, or `inferred`. Use `inferred` only for a no-patch diagnosis/report plan unless you can name the extra evidence you will collect before editing; inferred source patches are blocked by Fixer because they are not pull-request-ready. For `observed` source-patch plans, plan to say in the final `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. The plan must explain how the proposed code change addresses the observed issue evidence, call out any prior Fixer patch that should be improved or replaced, reject awkward control flow such as avoidable `goto` if there is a cleaner bounded alternative, name any local helper APIs or maintainer conventions the patch should follow, and keep the intended maintainer-facing explanation clear enough that someone unfamiliar with the local complaint wording can still follow the fix. In `## Validation`, name the reproducible configure/build/test entrypoint you will try from the workspace root before any focused leaf compile or smoke check, and include one bounded independent reproduction attempt for the collected failure signal when it is safe and cheap. Do not plan to claim `reproduced` unless that reproduction command or test can actually show the failure.

## Patch Pass

You are working on a bounded fixer proposal.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Produce the smallest reasonable patch for the target repository, keep the change upstreamable, prefer the clearest control flow available, and do not keep avoidable `goto` when a simpler structure would read better. Before introducing new file, process, allocation, locking, networking, or platform APIs, inspect nearby code and project contribution docs for existing helpers or compatibility wrappers and use those local patterns unless you can explain why they do not fit. Validate from a reproducible workspace-root entrypoint before falling back to focused leaf commands; if a build or test cannot run, report the exact command, the exact blocker, and any narrower check you ran instead. During validation, also try one bounded independent reproduction of the collected failure signal when it is safe and cheap, such as a failing test, smoke command, perf/strace comparison, or before/after runtime check. Only use `reproduced` if that command or test actually reproduced the failure; otherwise keep `observed` and report the reproduction blocker. The final explanation must connect the observed issue evidence to the actual code change, not just paraphrase the diff. Write like a maintainer is going to read the patch mail cold: explain the bug in plain language, define subsystem-specific jargon the first time you need it, and make the causal story obvious. Explicitly classify evidence confidence as `reproduced`, `observed`, or `inferred`: `reproduced` means you reproduced the failure locally; `observed` means Fixer has direct crash/log/trace evidence but you did not independently reproduce it; `inferred` means the source patch is not pull-request-ready, so do not leave a source diff unless you first gather stronger observed/reproduced evidence; otherwise return a no-patch diagnosis/report. For any source-changing `observed` patch, say explicitly in `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. If you introduce non-obvious state translation, index remapping, or backend split logic, add a short source comment that explains the invariant being preserved.

Start by explaining the likely root cause from the collected perf, strace, and /proc evidence. If you cannot land a safe patch, leave a diagnosis that is strong enough for an upstream bug report.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. 

Keep the change narrowly scoped and summarize validation clearly.

In every authoring pass, your final response must start with `Subject: <single-line git commit subject>` and then include these markdown sections exactly:

## Commit Message
A short upstream-friendly explanation of what changed and why. Write it in plain language that a maintainer can follow without local complaint context. If you use subsystem jargon, define it immediately.

## Evidence Confidence
Exactly one word: `reproduced`, `observed`, or `inferred`. Use `reproduced` only when you reproduced the failure locally with a command or test, and include that command/test in `## Validation`. Use `observed` when Fixer has direct crash/log/trace evidence but you did not independently reproduce it. If `## Git Add Paths` lists source files for an `observed` patch, `## Issue Connection` must explicitly say the failure was observed by Fixer and not independently reproduced. Use `inferred` for profiler/strace/indirect evidence; inferred responses may be no-patch diagnoses or reports, but inferred source patches are not pull-request-ready until stronger evidence is gathered.

## Issue Connection
Write this as maintainer-facing patch mail, not as local Fixer notes. Cover four things explicitly in readable sentences: the user-visible symptom or the exact collected signal, the code-level cause or the cautious inference from evidence, the specific change you made, and the expected effect. Do not invent a reproducer, command line, crash, or user-visible failure that is not present in the evidence bundle. If the evidence is direct-but-not-reproduced, say it was observed by Fixer and not independently reproduced. If the evidence is indirect and you did not gather stronger evidence, do not leave a source diff; write a no-patch diagnosis/report instead. Include an explicit effect sentence such as `The expected effect is ...`, `This should reduce ...`, or `This prevents ...` for source patches. If the logic is non-obvious in code, mention that you added a short explanatory comment.

## Git Add Paths
List the repo-relative paths that belong in the final patch, one per line. Use `None` only when you intentionally made no source changes. Include intentionally new files, and do not list generated build artifacts.

## Validation
List the checks you ran, or say clearly that you could not run them. Include the independent reproduction command/test and result when `## Evidence Confidence` is `reproduced`; if reproduction was attempted but blocked, name the exact blocker and keep confidence at `observed` or `inferred`.

Before editing, read the plan at `./plan-output.txt` and follow it unless the code proves part of it wrong. If you change course, say so explicitly in the final write-up instead of silently drifting from the plan.

## Review Pass 1

You are reviewing a freshly generated fixer patch.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Review the first patch pass. The original pre-edit snapshot is available at `./source` for diffing.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. The latest author response is at `./patch-output.txt`. Inspect the current code and changed paths like a strict code reviewer. Focus on correctness, regressions, maintainability, awkward control flow such as avoidable `goto`, missing validation, weak or non-gittable commit message text, and explanations that fail to connect the observed issue evidence to the code change. Also review the maintainer experience: the patch mail should be easy to accept upstream, the user-visible bug should be explained in plain language, subsystem-specific jargon should be defined when first used, and any non-obvious state translation or index remapping in code should have a short explanatory comment. Reject patches that omit `## Evidence Confidence`, use anything other than `reproduced`, `observed`, or `inferred`, or sound more certain than that evidence level allows. Reject patches that claim `reproduced` unless `## Validation` names the concrete reproduction command or test and its result. Reject patches that invent a reproducer, command line, crash, or user-visible failure not present in the evidence bundle; indirect profiler or strace evidence may justify a cautious mitigation, but the author must say it is indirect instead of presenting it as a confirmed upstream bug. Reject patches that introduce generic libc/std APIs when nearby code or project docs provide a local compat/helper API for the same job, unless the author explicitly justifies the exception. Reject validation that only reports a leaf object/syntax build when a project-level configure/build/test entrypoint exists and was not attempted; if a full build cannot run, the author must show the exact failed command and blocker.

Do not apply code changes in this pass.

Return a short markdown review report. The first non-empty line must be exactly one of:

RESULT: ok
RESULT: fix-needed

If you choose `RESULT: fix-needed`, add a `## Findings` section with concrete, actionable items.

Response

## Plan Pass

## Problem

Fixer observed `dockerd` started as `/usr/sbin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock` with low CPU, many sleeping threads, futex waits, and an automated `socket-churn` classification. The available evidence is profiler/strace/proc excerpts only; raw strace/fd artifacts referenced in `evidence.json` are not present in this workspace, and the stripped backtrace cannot be mapped to Go symbols.

## Evidence Confidence

inferred

## Proposed Subject

No source patch yet: collect symbolized dockerd socket/futex evidence before editing

## Patch Plan

Do not edit source in this pass. The evidence does not yet identify a source-level defect strongly enough for an upstreamable `docker.io`/Moby patch.

Before any future patch, collect stronger evidence by mapping the hot `dockerd` goroutines to source: obtain a symbolized goroutine dump or rebuild/run an unstripped `dockerd`, then repeat a bounded `strace -f -tt -e trace=futex,network` sample against the same `-H fd:// --containerd=...` startup shape.

If stronger evidence implicates socket activation/API serving, patch in `engine/daemon/listeners` or `engine/cmd/dockerd` following existing conventions: `log.G(ctx)` for logging, `github.com/docker/go-connections/sockets` for socket creation, `homedir.StickRuntimeDirContents` for runtime-dir socket handling, and existing `reexec`-based tests in `engine/cmd/dockerd/daemon_linux_test.go`. Avoid awkward `goto`; use bounded loops/timers like the existing `waitServe` pattern.

No prior Fixer source patch is present in the workspace (`git diff` is empty), so there is nothing to replace yet.

## Risks

A speculative source change could mask normal Go runtime futex parking or normal daemon idle behavior. The excerpt shows the process sleeping with very low CPU, while the `socket-churn` label is automated and not backed by available raw socket syscall details.

A future patch in listener/containerd reconnect paths could affect daemon startup under systemd socket activation, so it needs a focused regression test around `fd://` listener selection and shutdown/retry behavior.

## Validation

Primary workspace-root entrypoint to try after a real patch: `dpkg-buildpackage -us -uc -b`, which exercises the Debian build and the package test hooks from `debian/rules`.

Focused checks after that, if needed: `cd engine && make test-unit TESTDIRS=./cmd/dockerd TESTFLAGS='-run TestLoadListenerNoAddr'` or the equivalent Debian GOPATH test path after `dh_auto_configure`.

Bounded independent reproduction attempt before editing: run a short local `dockerd --validate`/listener-focused test and, only if a safe daemon instance is available, sample it with `timeout 10s strace -f -tt -e trace=futex,network` to see whether the collected futex/socket signal can actually be reproduced. Do not claim `reproduced` unless that command shows the same signal.

## Patch Pass

Subject: no source change for inferred dockerd socket-churn profile

## Commit Message

No patch was made. The collected data shows a sleeping `dockerd` with many futex waits and an automated socket-churn classification, but the available backtrace is stripped and the raw strace/fd artifacts are not present in this workspace. That is not enough to identify an upstream source defect.

## Evidence Confidence

inferred

## Issue Connection

The likely root cause cannot be established from the available evidence. The perf signal points at kernel scheduling, `/proc` shows `dockerd` sleeping with about `0.1%` CPU, and the included strace excerpt shows threads blocked in `FUTEX_WAIT_PRIVATE`. That can describe ordinary parked Go goroutines as well as a real retry loop. The bundle also labels the profile as `socket-churn`, but the raw socket syscall trace needed to connect that label to a Moby code path is unavailable here.

I followed the saved plan and did not change course: no source diff was left because an inferred source patch would not be pull-request-ready. I inspected Moby’s contribution/testing docs and the likely daemon paths. If stronger evidence later implicates listener setup, the relevant local conventions are `engine/daemon/listeners`, `github.com/docker/go-connections/sockets`, systemd activation helpers, `homedir.StickRuntimeDirContents`, `log.G(ctx)`, and the existing `reexec` socket-activation tests.

No code change was made. The expected effect is to avoid shipping a speculative daemon change until a symbolized goroutine dump, unstripped backtrace, or reproducible strace/perf sample ties the futex/socket signal to a specific Moby loop.

## Git Add Paths

None

## Validation

Read `./plan-output.txt` and followed its no-patch recommendation.

Workspace-root build preflight: `dpkg-checkbuilddeps` failed because build dependencies are not installed, starting with `dh-golang`, `golang-any`, `go-md2man`, and many Go `-dev` packages. Because of that blocker and because no source files changed, I did not run `dpkg-buildpackage -us -uc -b`.

Independent reproduction attempt: `ps -C dockerd -o pid=,args=` found no live `dockerd` process to sample. `strace` is installed, but without a safe target PID I could not repeat the futex/network trace. The raw evidence paths for `strace.log` and `fd-targets.txt` also do not exist in this sandbox.

Focused leaf check: `cd engine && go test ./cmd/dockerd -run TestLoadListenerNoAddr -count=1` failed before running tests because module imports are unavailable with lookup disabled by `-mod=readonly`; it also reported `GOCACHE`/`HOME` unset. `git diff --stat` and `git status --short` produced no output, confirming no local source changes.

## Review Pass 1

RESULT: ok

The first pass leaves no source diff, which matches the evidence level. The author response includes `## Evidence Confidence` with valid value `inferred`, avoids claiming a reproduced bug, and does not invent a user-visible failure beyond the profiler/strace evidence.

I found no changed paths in `git status`, `git diff --stat`, or `git diff`. The no-patch diagnosis is consistent with the bundle: stripped backtraces, futex waits, low CPU, and unavailable raw artifacts do not identify a pull-request-ready Moby source defect.

The response also names relevant local conventions for any future daemon/listener patch: `github.com/docker/go-connections/sockets`, systemd activation helpers, `homedir.StickRuntimeDirContents`, `log.G(ctx)`, and existing `reexec` tests. Validation is acceptable for a no-source-change pass: it reports the workspace-root build preflight blocker, the failed bounded reproduction attempt, and the focused test environment blocker.

diagnosis-only report

report

dockerd likely remains stuck in a socket churn loop. A diagnosis report and patch proposal were created locally.

state: readycreated: 2026-05-13 02:46 UTCvalidation: ready
Published session

Prompt

## Plan Pass

You are planning a fixer patch before any edits happen.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. The original pre-edit snapshot is available at `./source` if you need to inspect it. For interpreter processes, plan from the script/application entrypoint evidence first and include the runtime only as a second investigation target unless the evidence proves a runtime bug.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. Inspect the relevant code, nearby callers, project contribution docs, and local helper/compat APIs, but do not edit files in this pass.

Return a short markdown plan with these exact sections:

## Problem
## Evidence Confidence
## Proposed Subject
## Patch Plan
## Risks
## Validation

Classify `## Evidence Confidence` as exactly one of `reproduced`, `observed`, or `inferred`. Use `inferred` only for a no-patch diagnosis/report plan unless you can name the extra evidence you will collect before editing; inferred source patches are blocked by Fixer because they are not pull-request-ready. For `observed` source-patch plans, plan to say in the final `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. The plan must explain how the proposed code change addresses the observed issue evidence, call out any prior Fixer patch that should be improved or replaced, reject awkward control flow such as avoidable `goto` if there is a cleaner bounded alternative, name any local helper APIs or maintainer conventions the patch should follow, and keep the intended maintainer-facing explanation clear enough that someone unfamiliar with the local complaint wording can still follow the fix. In `## Validation`, name the reproducible configure/build/test entrypoint you will try from the workspace root before any focused leaf compile or smoke check, and include one bounded independent reproduction attempt for the collected failure signal when it is safe and cheap. Do not plan to claim `reproduced` unless that reproduction command or test can actually show the failure.

## Patch Pass

You are working on a bounded fixer proposal.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Produce the smallest reasonable patch for the target repository, keep the change upstreamable, prefer the clearest control flow available, and do not keep avoidable `goto` when a simpler structure would read better. Before introducing new file, process, allocation, locking, networking, or platform APIs, inspect nearby code and project contribution docs for existing helpers or compatibility wrappers and use those local patterns unless you can explain why they do not fit. Validate from a reproducible workspace-root entrypoint before falling back to focused leaf commands; if a build or test cannot run, report the exact command, the exact blocker, and any narrower check you ran instead. During validation, also try one bounded independent reproduction of the collected failure signal when it is safe and cheap, such as a failing test, smoke command, perf/strace comparison, or before/after runtime check. Only use `reproduced` if that command or test actually reproduced the failure; otherwise keep `observed` and report the reproduction blocker. The final explanation must connect the observed issue evidence to the actual code change, not just paraphrase the diff. Write like a maintainer is going to read the patch mail cold: explain the bug in plain language, define subsystem-specific jargon the first time you need it, and make the causal story obvious. Explicitly classify evidence confidence as `reproduced`, `observed`, or `inferred`: `reproduced` means you reproduced the failure locally; `observed` means Fixer has direct crash/log/trace evidence but you did not independently reproduce it; `inferred` means the source patch is not pull-request-ready, so do not leave a source diff unless you first gather stronger observed/reproduced evidence; otherwise return a no-patch diagnosis/report. For any source-changing `observed` patch, say explicitly in `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. If you introduce non-obvious state translation, index remapping, or backend split logic, add a short source comment that explains the invariant being preserved.

Start by explaining the likely root cause from the collected perf, strace, and /proc evidence. If you cannot land a safe patch, leave a diagnosis that is strong enough for an upstream bug report.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. 

Keep the change narrowly scoped and summarize validation clearly.

In every authoring pass, your final response must start with `Subject: <single-line git commit subject>` and then include these markdown sections exactly:

## Commit Message
A short upstream-friendly explanation of what changed and why. Write it in plain language that a maintainer can follow without local complaint context. If you use subsystem jargon, define it immediately.

## Evidence Confidence
Exactly one word: `reproduced`, `observed`, or `inferred`. Use `reproduced` only when you reproduced the failure locally with a command or test, and include that command/test in `## Validation`. Use `observed` when Fixer has direct crash/log/trace evidence but you did not independently reproduce it. If `## Git Add Paths` lists source files for an `observed` patch, `## Issue Connection` must explicitly say the failure was observed by Fixer and not independently reproduced. Use `inferred` for profiler/strace/indirect evidence; inferred responses may be no-patch diagnoses or reports, but inferred source patches are not pull-request-ready until stronger evidence is gathered.

## Issue Connection
Write this as maintainer-facing patch mail, not as local Fixer notes. Cover four things explicitly in readable sentences: the user-visible symptom or the exact collected signal, the code-level cause or the cautious inference from evidence, the specific change you made, and the expected effect. Do not invent a reproducer, command line, crash, or user-visible failure that is not present in the evidence bundle. If the evidence is direct-but-not-reproduced, say it was observed by Fixer and not independently reproduced. If the evidence is indirect and you did not gather stronger evidence, do not leave a source diff; write a no-patch diagnosis/report instead. Include an explicit effect sentence such as `The expected effect is ...`, `This should reduce ...`, or `This prevents ...` for source patches. If the logic is non-obvious in code, mention that you added a short explanatory comment.

## Git Add Paths
List the repo-relative paths that belong in the final patch, one per line. Use `None` only when you intentionally made no source changes. Include intentionally new files, and do not list generated build artifacts.

## Validation
List the checks you ran, or say clearly that you could not run them. Include the independent reproduction command/test and result when `## Evidence Confidence` is `reproduced`; if reproduction was attempted but blocked, name the exact blocker and keep confidence at `observed` or `inferred`.

Before editing, read the plan at `./plan-output.txt` and follow it unless the code proves part of it wrong. If you change course, say so explicitly in the final write-up instead of silently drifting from the plan.

## Review Pass 1

You are reviewing a freshly generated fixer patch.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Review the first patch pass. The original pre-edit snapshot is available at `./source` for diffing.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. The latest author response is at `./patch-output.txt`. Inspect the current code and changed paths like a strict code reviewer. Focus on correctness, regressions, maintainability, awkward control flow such as avoidable `goto`, missing validation, weak or non-gittable commit message text, and explanations that fail to connect the observed issue evidence to the code change. Also review the maintainer experience: the patch mail should be easy to accept upstream, the user-visible bug should be explained in plain language, subsystem-specific jargon should be defined when first used, and any non-obvious state translation or index remapping in code should have a short explanatory comment. Reject patches that omit `## Evidence Confidence`, use anything other than `reproduced`, `observed`, or `inferred`, or sound more certain than that evidence level allows. Reject patches that claim `reproduced` unless `## Validation` names the concrete reproduction command or test and its result. Reject patches that invent a reproducer, command line, crash, or user-visible failure not present in the evidence bundle; indirect profiler or strace evidence may justify a cautious mitigation, but the author must say it is indirect instead of presenting it as a confirmed upstream bug. Reject patches that introduce generic libc/std APIs when nearby code or project docs provide a local compat/helper API for the same job, unless the author explicitly justifies the exception. Reject validation that only reports a leaf object/syntax build when a project-level configure/build/test entrypoint exists and was not attempted; if a full build cannot run, the author must show the exact failed command and blocker.

Do not apply code changes in this pass.

Return a short markdown review report. The first non-empty line must be exactly one of:

RESULT: ok
RESULT: fix-needed

If you choose `RESULT: fix-needed`, add a `## Findings` section with concrete, actionable items.

Response

## Plan Pass

## Problem
Fixer observed `/usr/sbin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock` with 185 threads, process state `S (sleeping)`, very low CPU, and sampled stacks dominated by `futex` / `__schedule`. The bundle’s “socket-churn” label is indirect; embedded `strace` lines mostly show futex waits and `waitid(P_PIDFD, ...)`, and the raw artifact files referenced by the JSON are not available in this workspace.

## Evidence Confidence
inferred

## Proposed Subject
No source patch yet: diagnose insufficient evidence for an upstream-ready `docker.io`/Moby patch. A later patch would need a concrete daemon code path, symbolized goroutine/profile data, or a reproducible API/listener/containerd interaction before editing.

## Patch Plan
Do not edit files in this pass. The current evidence does not identify a failing Moby function, a reproducible user-visible behavior, or a confirmed busy loop; it shows a sleeping Go daemon with many goroutines blocked in futex waits, which can be normal for an idle or connection-heavy daemon.

Contribution/style docs checked: `engine/CONTRIBUTING.md`, `engine/README.md`, `engine/TESTING.md`, and `engine/docs/contributing/test.md`. Maintainer conventions found: daemon work belongs under `engine/daemon` or `engine/cmd/dockerd`; changes need focused unit tests; run `gofmt -s`; avoid new `integration-cli` tests.

Relevant local helpers/conventions found: listener setup goes through `engine/daemon/listeners.Init` and `listenFD` for `fd://`; socket creation uses `github.com/docker/go-connections/sockets`; daemon logging uses `log.G(ctx)` from `github.com/containerd/log`; API serving uses Go `http.Server` with bounded shutdown handling in `engine/cmd/dockerd/daemon.go`. Any future patch should use those helpers instead of ad hoc socket or logging code.

No prior Fixer patch was referenced in the evidence, and scanning the workspace did not find a Fixer-specific patch for this issue. If later evidence points at listener shutdown or FD selection, prefer a small helper or early-return branch over awkward control flow such as avoidable `goto`.

## Risks
Patching from this evidence would risk changing daemon listener, HTTP server, or containerd-supervision behavior based on scheduler/runtime symptoms rather than a proven Moby defect.

A patch aimed only at reducing observed futex waits could mask normal Go runtime blocking behavior and would likely be rejected upstream without a concrete reproduction or symbolized goroutine evidence.

## Validation
Before any future edit, use the reproducible package entrypoint from the workspace root: `dpkg-buildpackage -us -uc -b`, which drives Debian’s `debian/rules` build and test flow, including `engine/hack/test/unit`.

For a focused upstream check after a justified Moby change, run from `engine`: `TESTDIRS='<changed package>' TESTFLAGS='-test.run <focused test>' make test-unit`.

Bounded independent reproduction attempt: if a local `dockerd` is present, sample only `/proc/$pid/status`, `/proc/$pid/wchan`, and `/proc/$pid/task/*/wchan` for a few seconds to see whether the same sleeping/high-thread/futex-wait signal exists. Do not claim `reproduced` unless that command actually shows the same signal.

## Patch Pass

Subject: Diagnose dockerd futex profile evidence

## Commit Message
No source change was made. The collected evidence points to a sleeping Go daemon with many parked goroutines or child-wait goroutines, not to a confirmed Moby code defect. A patch would need symbolized goroutine data, logs, or a reproducer tying the futex waits to a specific daemon path.

## Evidence Confidence
inferred

## Issue Connection
Fixer collected profiler, `strace`, and `/proc` excerpts for `dockerd -H fd:// --containerd=/run/containerd/containerd.sock`: 185 threads, process state `S (sleeping)`, 0.1% CPU, kernel samples in `__schedule`, and `strace` lines dominated by `futex(FUTEX_WAIT_PRIVATE, ...)` with a few `waitid(P_PIDFD, ...)` calls.

The cautious inference is that the daemon was mostly idle or blocked in normal Go runtime synchronization and child-process waiting. The evidence does not identify a user-visible failure, a hot Moby function, a tight retry loop, or a broken listener/containerd path. The raw artifact files referenced by `evidence.json` were not present, so I could not inspect full `strace`, file descriptors, or symbolized stacks.

I followed the saved plan and left no source diff. I inspected the relevant `fd://` and API-serving code and found the local helpers/patterns a future patch should use: `engine/daemon/listeners.Init`, `listenFD`, `github.com/docker/go-connections/sockets`, and `log.G(ctx)`. Moby contribution docs also require focused tests, `gofmt -s`, and daemon changes under the appropriate `engine/daemon` or `engine/cmd/dockerd` packages.

The expected effect of this no-patch diagnosis is to avoid an upstream-unready speculative change. A useful upstream report should request or include symbolized goroutine dumps, full `strace`/FD data, and a reproducible daemon workload before proposing code changes.

## Git Add Paths
None

## Validation
`timeout 60s dpkg-buildpackage -us -uc -b` from the workspace root failed before build/test with `dpkg-checkbuilddeps: error: unmet build dependencies`, including `dh-golang`, `golang-any`, `go-md2man`, and many Go library build dependencies. No narrower source test was run because there is no source change.

Independent reproduction attempt: `pid=$(pgrep -x dockerd | head -n1 || true); ... /proc/$pid/status ...` reported `no local dockerd process found`, so the futex/sleeping-thread signal was not reproduced locally.

`git status --short && git diff --exit-code` passed with no workspace changes.

## Review Pass 1

RESULT: ok

No source changes are present, which matches the `inferred` evidence level and the saved plan. The author does not overclaim reproduction, identifies the evidence as profiler/trace-based, names the relevant Moby helpers and conventions, and reports the workspace-root build attempt plus its dependency blocker.

The no-patch diagnosis is appropriate for the available evidence.

diagnosis-only report

report

dockerd likely remains stuck in a socket churn loop. A diagnosis report and patch proposal were created locally.

state: readycreated: 2026-05-13 02:46 UTCvalidation: ready
Published session

Prompt

## Plan Pass

You are planning a fixer patch before any edits happen.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. The original pre-edit snapshot is available at `./source` if you need to inspect it. For interpreter processes, plan from the script/application entrypoint evidence first and include the runtime only as a second investigation target unless the evidence proves a runtime bug.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. Inspect the relevant code, nearby callers, project contribution docs, and local helper/compat APIs, but do not edit files in this pass.

Return a short markdown plan with these exact sections:

## Problem
## Evidence Confidence
## Proposed Subject
## Patch Plan
## Risks
## Validation

Classify `## Evidence Confidence` as exactly one of `reproduced`, `observed`, or `inferred`. Use `inferred` only for a no-patch diagnosis/report plan unless you can name the extra evidence you will collect before editing; inferred source patches are blocked by Fixer because they are not pull-request-ready. For `observed` source-patch plans, plan to say in the final `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. The plan must explain how the proposed code change addresses the observed issue evidence, call out any prior Fixer patch that should be improved or replaced, reject awkward control flow such as avoidable `goto` if there is a cleaner bounded alternative, name any local helper APIs or maintainer conventions the patch should follow, and keep the intended maintainer-facing explanation clear enough that someone unfamiliar with the local complaint wording can still follow the fix. In `## Validation`, name the reproducible configure/build/test entrypoint you will try from the workspace root before any focused leaf compile or smoke check, and include one bounded independent reproduction attempt for the collected failure signal when it is safe and cheap. Do not plan to claim `reproduced` unless that reproduction command or test can actually show the failure.

## Patch Pass

You are working on a bounded fixer proposal.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Produce the smallest reasonable patch for the target repository, keep the change upstreamable, prefer the clearest control flow available, and do not keep avoidable `goto` when a simpler structure would read better. Before introducing new file, process, allocation, locking, networking, or platform APIs, inspect nearby code and project contribution docs for existing helpers or compatibility wrappers and use those local patterns unless you can explain why they do not fit. Validate from a reproducible workspace-root entrypoint before falling back to focused leaf commands; if a build or test cannot run, report the exact command, the exact blocker, and any narrower check you ran instead. During validation, also try one bounded independent reproduction of the collected failure signal when it is safe and cheap, such as a failing test, smoke command, perf/strace comparison, or before/after runtime check. Only use `reproduced` if that command or test actually reproduced the failure; otherwise keep `observed` and report the reproduction blocker. The final explanation must connect the observed issue evidence to the actual code change, not just paraphrase the diff. Write like a maintainer is going to read the patch mail cold: explain the bug in plain language, define subsystem-specific jargon the first time you need it, and make the causal story obvious. Explicitly classify evidence confidence as `reproduced`, `observed`, or `inferred`: `reproduced` means you reproduced the failure locally; `observed` means Fixer has direct crash/log/trace evidence but you did not independently reproduce it; `inferred` means the source patch is not pull-request-ready, so do not leave a source diff unless you first gather stronger observed/reproduced evidence; otherwise return a no-patch diagnosis/report. For any source-changing `observed` patch, say explicitly in `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. If you introduce non-obvious state translation, index remapping, or backend split logic, add a short source comment that explains the invariant being preserved.

Start by explaining the likely root cause from the collected perf, strace, and /proc evidence. If you cannot land a safe patch, leave a diagnosis that is strong enough for an upstream bug report.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. 

Keep the change narrowly scoped and summarize validation clearly.

In every authoring pass, your final response must start with `Subject: <single-line git commit subject>` and then include these markdown sections exactly:

## Commit Message
A short upstream-friendly explanation of what changed and why. Write it in plain language that a maintainer can follow without local complaint context. If you use subsystem jargon, define it immediately.

## Evidence Confidence
Exactly one word: `reproduced`, `observed`, or `inferred`. Use `reproduced` only when you reproduced the failure locally with a command or test, and include that command/test in `## Validation`. Use `observed` when Fixer has direct crash/log/trace evidence but you did not independently reproduce it. If `## Git Add Paths` lists source files for an `observed` patch, `## Issue Connection` must explicitly say the failure was observed by Fixer and not independently reproduced. Use `inferred` for profiler/strace/indirect evidence; inferred responses may be no-patch diagnoses or reports, but inferred source patches are not pull-request-ready until stronger evidence is gathered.

## Issue Connection
Write this as maintainer-facing patch mail, not as local Fixer notes. Cover four things explicitly in readable sentences: the user-visible symptom or the exact collected signal, the code-level cause or the cautious inference from evidence, the specific change you made, and the expected effect. Do not invent a reproducer, command line, crash, or user-visible failure that is not present in the evidence bundle. If the evidence is direct-but-not-reproduced, say it was observed by Fixer and not independently reproduced. If the evidence is indirect and you did not gather stronger evidence, do not leave a source diff; write a no-patch diagnosis/report instead. Include an explicit effect sentence such as `The expected effect is ...`, `This should reduce ...`, or `This prevents ...` for source patches. If the logic is non-obvious in code, mention that you added a short explanatory comment.

## Git Add Paths
List the repo-relative paths that belong in the final patch, one per line. Use `None` only when you intentionally made no source changes. Include intentionally new files, and do not list generated build artifacts.

## Validation
List the checks you ran, or say clearly that you could not run them. Include the independent reproduction command/test and result when `## Evidence Confidence` is `reproduced`; if reproduction was attempted but blocked, name the exact blocker and keep confidence at `observed` or `inferred`.

Before editing, read the plan at `./plan-output.txt` and follow it unless the code proves part of it wrong. If you change course, say so explicitly in the final write-up instead of silently drifting from the plan.

## Review Pass 1

You are reviewing a freshly generated fixer patch.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Review the first patch pass. The original pre-edit snapshot is available at `./source` for diffing.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. The latest author response is at `./patch-output.txt`. Inspect the current code and changed paths like a strict code reviewer. Focus on correctness, regressions, maintainability, awkward control flow such as avoidable `goto`, missing validation, weak or non-gittable commit message text, and explanations that fail to connect the observed issue evidence to the code change. Also review the maintainer experience: the patch mail should be easy to accept upstream, the user-visible bug should be explained in plain language, subsystem-specific jargon should be defined when first used, and any non-obvious state translation or index remapping in code should have a short explanatory comment. Reject patches that omit `## Evidence Confidence`, use anything other than `reproduced`, `observed`, or `inferred`, or sound more certain than that evidence level allows. Reject patches that claim `reproduced` unless `## Validation` names the concrete reproduction command or test and its result. Reject patches that invent a reproducer, command line, crash, or user-visible failure not present in the evidence bundle; indirect profiler or strace evidence may justify a cautious mitigation, but the author must say it is indirect instead of presenting it as a confirmed upstream bug. Reject patches that introduce generic libc/std APIs when nearby code or project docs provide a local compat/helper API for the same job, unless the author explicitly justifies the exception. Reject validation that only reports a leaf object/syntax build when a project-level configure/build/test entrypoint exists and was not attempted; if a full build cannot run, the author must show the exact failed command and blocker.

Do not apply code changes in this pass.

Return a short markdown review report. The first non-empty line must be exactly one of:

RESULT: ok
RESULT: fix-needed

If you choose `RESULT: fix-needed`, add a `## Findings` section with concrete, actionable items.

Response

## Plan Pass

## Problem
Fixer observed `/usr/sbin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock` with 185 threads, process state `S (sleeping)`, very low CPU, and sampled stacks dominated by `futex` / `__schedule`. The bundle’s “socket-churn” label is indirect; embedded `strace` lines mostly show futex waits and `waitid(P_PIDFD, ...)`, and the raw artifact files referenced by the JSON are not available in this workspace.

## Evidence Confidence
inferred

## Proposed Subject
No source patch yet: diagnose insufficient evidence for an upstream-ready `docker.io`/Moby patch. A later patch would need a concrete daemon code path, symbolized goroutine/profile data, or a reproducible API/listener/containerd interaction before editing.

## Patch Plan
Do not edit files in this pass. The current evidence does not identify a failing Moby function, a reproducible user-visible behavior, or a confirmed busy loop; it shows a sleeping Go daemon with many goroutines blocked in futex waits, which can be normal for an idle or connection-heavy daemon.

Contribution/style docs checked: `engine/CONTRIBUTING.md`, `engine/README.md`, `engine/TESTING.md`, and `engine/docs/contributing/test.md`. Maintainer conventions found: daemon work belongs under `engine/daemon` or `engine/cmd/dockerd`; changes need focused unit tests; run `gofmt -s`; avoid new `integration-cli` tests.

Relevant local helpers/conventions found: listener setup goes through `engine/daemon/listeners.Init` and `listenFD` for `fd://`; socket creation uses `github.com/docker/go-connections/sockets`; daemon logging uses `log.G(ctx)` from `github.com/containerd/log`; API serving uses Go `http.Server` with bounded shutdown handling in `engine/cmd/dockerd/daemon.go`. Any future patch should use those helpers instead of ad hoc socket or logging code.

No prior Fixer patch was referenced in the evidence, and scanning the workspace did not find a Fixer-specific patch for this issue. If later evidence points at listener shutdown or FD selection, prefer a small helper or early-return branch over awkward control flow such as avoidable `goto`.

## Risks
Patching from this evidence would risk changing daemon listener, HTTP server, or containerd-supervision behavior based on scheduler/runtime symptoms rather than a proven Moby defect.

A patch aimed only at reducing observed futex waits could mask normal Go runtime blocking behavior and would likely be rejected upstream without a concrete reproduction or symbolized goroutine evidence.

## Validation
Before any future edit, use the reproducible package entrypoint from the workspace root: `dpkg-buildpackage -us -uc -b`, which drives Debian’s `debian/rules` build and test flow, including `engine/hack/test/unit`.

For a focused upstream check after a justified Moby change, run from `engine`: `TESTDIRS='<changed package>' TESTFLAGS='-test.run <focused test>' make test-unit`.

Bounded independent reproduction attempt: if a local `dockerd` is present, sample only `/proc/$pid/status`, `/proc/$pid/wchan`, and `/proc/$pid/task/*/wchan` for a few seconds to see whether the same sleeping/high-thread/futex-wait signal exists. Do not claim `reproduced` unless that command actually shows the same signal.

## Patch Pass

Subject: Diagnose dockerd futex profile evidence

## Commit Message
No source change was made. The collected evidence points to a sleeping Go daemon with many parked goroutines or child-wait goroutines, not to a confirmed Moby code defect. A patch would need symbolized goroutine data, logs, or a reproducer tying the futex waits to a specific daemon path.

## Evidence Confidence
inferred

## Issue Connection
Fixer collected profiler, `strace`, and `/proc` excerpts for `dockerd -H fd:// --containerd=/run/containerd/containerd.sock`: 185 threads, process state `S (sleeping)`, 0.1% CPU, kernel samples in `__schedule`, and `strace` lines dominated by `futex(FUTEX_WAIT_PRIVATE, ...)` with a few `waitid(P_PIDFD, ...)` calls.

The cautious inference is that the daemon was mostly idle or blocked in normal Go runtime synchronization and child-process waiting. The evidence does not identify a user-visible failure, a hot Moby function, a tight retry loop, or a broken listener/containerd path. The raw artifact files referenced by `evidence.json` were not present, so I could not inspect full `strace`, file descriptors, or symbolized stacks.

I followed the saved plan and left no source diff. I inspected the relevant `fd://` and API-serving code and found the local helpers/patterns a future patch should use: `engine/daemon/listeners.Init`, `listenFD`, `github.com/docker/go-connections/sockets`, and `log.G(ctx)`. Moby contribution docs also require focused tests, `gofmt -s`, and daemon changes under the appropriate `engine/daemon` or `engine/cmd/dockerd` packages.

The expected effect of this no-patch diagnosis is to avoid an upstream-unready speculative change. A useful upstream report should request or include symbolized goroutine dumps, full `strace`/FD data, and a reproducible daemon workload before proposing code changes.

## Git Add Paths
None

## Validation
`timeout 60s dpkg-buildpackage -us -uc -b` from the workspace root failed before build/test with `dpkg-checkbuilddeps: error: unmet build dependencies`, including `dh-golang`, `golang-any`, `go-md2man`, and many Go library build dependencies. No narrower source test was run because there is no source change.

Independent reproduction attempt: `pid=$(pgrep -x dockerd | head -n1 || true); ... /proc/$pid/status ...` reported `no local dockerd process found`, so the futex/sleeping-thread signal was not reproduced locally.

`git status --short && git diff --exit-code` passed with no workspace changes.

## Review Pass 1

RESULT: ok

No source changes are present, which matches the `inferred` evidence level and the saved plan. The author does not overclaim reproduction, identifies the evidence as profiler/trace-based, names the relevant Moby helpers and conventions, and reports the workspace-root build attempt plus its dependency blocker.

The no-patch diagnosis is appropriate for the available evidence.

diagnosis-only report

report

dockerd likely remains stuck in a socket churn loop. A diagnosis report and patch proposal were created locally.

state: readycreated: 2026-05-13 01:36 UTCvalidation: ready
Published session

Prompt

## Plan Pass

You are planning a fixer patch before any edits happen.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. The original pre-edit snapshot is available at `./source` if you need to inspect it. For interpreter processes, plan from the script/application entrypoint evidence first and include the runtime only as a second investigation target unless the evidence proves a runtime bug.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. Inspect the relevant code, nearby callers, project contribution docs, and local helper/compat APIs, but do not edit files in this pass.

Return a short markdown plan with these exact sections:

## Problem
## Evidence Confidence
## Proposed Subject
## Patch Plan
## Risks
## Validation

Classify `## Evidence Confidence` as exactly one of `reproduced`, `observed`, or `inferred`. Use `inferred` only for a no-patch diagnosis/report plan unless you can name the extra evidence you will collect before editing; inferred source patches are blocked by Fixer because they are not pull-request-ready. For `observed` source-patch plans, plan to say in the final `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. The plan must explain how the proposed code change addresses the observed issue evidence, call out any prior Fixer patch that should be improved or replaced, reject awkward control flow such as avoidable `goto` if there is a cleaner bounded alternative, name any local helper APIs or maintainer conventions the patch should follow, and keep the intended maintainer-facing explanation clear enough that someone unfamiliar with the local complaint wording can still follow the fix. In `## Validation`, name the reproducible configure/build/test entrypoint you will try from the workspace root before any focused leaf compile or smoke check, and include one bounded independent reproduction attempt for the collected failure signal when it is safe and cheap. Do not plan to claim `reproduced` unless that reproduction command or test can actually show the failure.

## Patch Pass

You are working on a bounded fixer proposal.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Produce the smallest reasonable patch for the target repository, keep the change upstreamable, prefer the clearest control flow available, and do not keep avoidable `goto` when a simpler structure would read better. Before introducing new file, process, allocation, locking, networking, or platform APIs, inspect nearby code and project contribution docs for existing helpers or compatibility wrappers and use those local patterns unless you can explain why they do not fit. Validate from a reproducible workspace-root entrypoint before falling back to focused leaf commands; if a build or test cannot run, report the exact command, the exact blocker, and any narrower check you ran instead. During validation, also try one bounded independent reproduction of the collected failure signal when it is safe and cheap, such as a failing test, smoke command, perf/strace comparison, or before/after runtime check. Only use `reproduced` if that command or test actually reproduced the failure; otherwise keep `observed` and report the reproduction blocker. The final explanation must connect the observed issue evidence to the actual code change, not just paraphrase the diff. Write like a maintainer is going to read the patch mail cold: explain the bug in plain language, define subsystem-specific jargon the first time you need it, and make the causal story obvious. Explicitly classify evidence confidence as `reproduced`, `observed`, or `inferred`: `reproduced` means you reproduced the failure locally; `observed` means Fixer has direct crash/log/trace evidence but you did not independently reproduce it; `inferred` means the source patch is not pull-request-ready, so do not leave a source diff unless you first gather stronger observed/reproduced evidence; otherwise return a no-patch diagnosis/report. For any source-changing `observed` patch, say explicitly in `## Issue Connection` that the failure was observed by Fixer and not independently reproduced. If you introduce non-obvious state translation, index remapping, or backend split logic, add a short source comment that explains the invariant being preserved.

Start by explaining the likely root cause from the collected perf, strace, and /proc evidence. If you cannot land a safe patch, leave a diagnosis that is strong enough for an upstream bug report.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. 

Keep the change narrowly scoped and summarize validation clearly.

In every authoring pass, your final response must start with `Subject: <single-line git commit subject>` and then include these markdown sections exactly:

## Commit Message
A short upstream-friendly explanation of what changed and why. Write it in plain language that a maintainer can follow without local complaint context. If you use subsystem jargon, define it immediately.

## Evidence Confidence
Exactly one word: `reproduced`, `observed`, or `inferred`. Use `reproduced` only when you reproduced the failure locally with a command or test, and include that command/test in `## Validation`. Use `observed` when Fixer has direct crash/log/trace evidence but you did not independently reproduce it. If `## Git Add Paths` lists source files for an `observed` patch, `## Issue Connection` must explicitly say the failure was observed by Fixer and not independently reproduced. Use `inferred` for profiler/strace/indirect evidence; inferred responses may be no-patch diagnoses or reports, but inferred source patches are not pull-request-ready until stronger evidence is gathered.

## Issue Connection
Write this as maintainer-facing patch mail, not as local Fixer notes. Cover four things explicitly in readable sentences: the user-visible symptom or the exact collected signal, the code-level cause or the cautious inference from evidence, the specific change you made, and the expected effect. Do not invent a reproducer, command line, crash, or user-visible failure that is not present in the evidence bundle. If the evidence is direct-but-not-reproduced, say it was observed by Fixer and not independently reproduced. If the evidence is indirect and you did not gather stronger evidence, do not leave a source diff; write a no-patch diagnosis/report instead. Include an explicit effect sentence such as `The expected effect is ...`, `This should reduce ...`, or `This prevents ...` for source patches. If the logic is non-obvious in code, mention that you added a short explanatory comment.

## Git Add Paths
List the repo-relative paths that belong in the final patch, one per line. Use `None` only when you intentionally made no source changes. Include intentionally new files, and do not list generated build artifacts.

## Validation
List the checks you ran, or say clearly that you could not run them. Include the independent reproduction command/test and result when `## Evidence Confidence` is `reproduced`; if reproduction was attempted but blocked, name the exact blocker and keep confidence at `observed` or `inferred`.

Before editing, read the plan at `./plan-output.txt` and follow it unless the code proves part of it wrong. If you change course, say so explicitly in the final write-up instead of silently drifting from the plan.

## Review Pass 1

You are reviewing a freshly generated fixer patch.

Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. Review the first patch pass. The original pre-edit snapshot is available at `./source` for diffing.

Upstream-style expectation: before planning or editing, check for contribution/style docs (`CONTRIBUTING`, `HACKING`, `README-hacking`, `README.md`, `docs/`, `dev-docs/`) and scan the touched subsystem for local helpers. If the project has wrappers for file IO, path-relative IO, process spawning, memory allocation, logging, locking, or platform compatibility, prefer those wrappers over generic libc/std APIs. Do not invent a reproducer or user-visible failure that is not in the evidence bundle; if the evidence is profiler-only or indirect, describe it as a targeted mitigation or stop with a diagnosis instead of presenting a speculative patch as a confirmed bug fix. In the plan and final validation, name any such helper, convention, or evidence limit you found, or say that no relevant local helper was found. Treat this as a `docker.io` upstream patch, not just a Debian-local workaround. The latest author response is at `./patch-output.txt`. Inspect the current code and changed paths like a strict code reviewer. Focus on correctness, regressions, maintainability, awkward control flow such as avoidable `goto`, missing validation, weak or non-gittable commit message text, and explanations that fail to connect the observed issue evidence to the code change. Also review the maintainer experience: the patch mail should be easy to accept upstream, the user-visible bug should be explained in plain language, subsystem-specific jargon should be defined when first used, and any non-obvious state translation or index remapping in code should have a short explanatory comment. Reject patches that omit `## Evidence Confidence`, use anything other than `reproduced`, `observed`, or `inferred`, or sound more certain than that evidence level allows. Reject patches that claim `reproduced` unless `## Validation` names the concrete reproduction command or test and its result. Reject patches that invent a reproducer, command line, crash, or user-visible failure not present in the evidence bundle; indirect profiler or strace evidence may justify a cautious mitigation, but the author must say it is indirect instead of presenting it as a confirmed upstream bug. Reject patches that introduce generic libc/std APIs when nearby code or project docs provide a local compat/helper API for the same job, unless the author explicitly justifies the exception. Reject validation that only reports a leaf object/syntax build when a project-level configure/build/test entrypoint exists and was not attempted; if a full build cannot run, the author must show the exact failed command and blocker.

Do not apply code changes in this pass.

Return a short markdown review report. The first non-empty line must be exactly one of:

RESULT: ok
RESULT: fix-needed

If you choose `RESULT: fix-needed`, add a `## Findings` section with concrete, actionable items.

Response

## Plan Pass

## Problem
Fixer observed `dockerd` running as `/usr/sbin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock` with 185 threads, process state `S (sleeping)`, very low CPU (`0.1%`), kernel stack in futex wait, and a classifier label of `socket-churn`. The embedded excerpts do not identify a Go symbol, request path, listener, plugin, or containerd callsite. The referenced raw artifacts are not present in this workspace, so there is no actionable source-level failure yet.

## Evidence Confidence
inferred

## Proposed Subject
No source patch yet: collect symbolized `dockerd` goroutine/profile evidence before changing listener or socket-activation code.

## Patch Plan
Do not edit files in this pass. Treat this as a diagnosis/report plan, because an upstream-style patch would otherwise invent a bug from indirect profiler evidence.

Investigate from the application entrypoint first: `engine/cmd/dockerd/docker.go`, then `engine/cmd/dockerd/daemon.go`, especially `loadListeners`, `runDaemon`, and the API `httpServer.Serve` goroutines. Only investigate Go runtime futex behavior second, because the evidence shows sleeping futex waits but not a runtime defect.

Relevant local helpers/conventions found: `listeners.Init`, `listenFD`, `github.com/coreos/go-systemd/v22/activation.Listeners/TLSListeners`, `github.com/docker/go-connections/sockets`, `homedir.StickRuntimeDirContents`, `log.G(ctx)`, and `errors.Wrap/Wrapf`. Any future patch should follow those helpers and existing early-return style; avoid awkward control flow such as adding `goto` around bounded listener cleanup.

No prior Fixer patch or marker for this issue was found in the workspace. Debian patches are packaging/build/test oriented and do not appear to address this evidence.

## Risks
A source patch now would be speculative. The evidence mixes a `socket-churn` classification with excerpts dominated by futex waits and `waitid`, while the target process is sleeping with negligible CPU. That can describe a normal idle daemon with many goroutines, not necessarily a daemon bug.

Changing socket activation or API serve loops without a symbolized stack could regress systemd `fd://` startup, TLS listener activation, or shutdown behavior.

## Validation
Before any focused leaf check, use the workspace-root Debian entrypoint: `DEB_BUILD_OPTIONS=nocheck debian/rules build`. For focused checks after a real hypothesis, use `cd engine && go test ./daemon/listeners ./cmd/dockerd` if dependencies are available.

Bounded independent reproduction attempt: after building, run a short `dockerd` smoke under `timeout` with an isolated temp `--data-root`, `--exec-root`, `--pidfile`, and `-H unix://...`, capturing `strace -f -e trace=futex,network`. Only classify as `reproduced` if that command shows the same collected failure signal, not merely ordinary idle futex waits.

## Patch Pass

Subject: dockerd: Diagnose unsymbolized futex profile

## Commit Message
No source patch was produced. The likely root cause from the collected perf, strace, and `/proc` evidence is an idle or blocked `dockerd` with many goroutines/threads sleeping in futex waits, not an identified `dockerd` socket loop. The evidence does not include a symbolized Go stack or request path tying the signal to listener code.

## Evidence Confidence
inferred

## Issue Connection
The collected signal is `dockerd -H fd:// --containerd=/run/containerd/containerd.sock` in `S (sleeping)` state with 185 threads, `0.1%` CPU, perf hot path in kernel scheduling, `/proc` stack in `futex_wait`, and strace excerpts dominated by `FUTEX_WAIT_PRIVATE` plus some `waitid(P_PIDFD, ...)`. A classifier called this `socket-churn`, but the embedded syscall excerpt does not show repeated socket operations, and the raw strace/GDB files referenced by the bundle are missing from this workspace.

Following the saved plan, I inspected the application entrypoint and listener path first: `engine/cmd/dockerd/docker.go`, `engine/cmd/dockerd/daemon.go`, and `engine/daemon/listeners/listeners_linux.go`. The relevant local patterns are already centralized helpers: `listeners.Init`, `listenFD`, `activation.Listeners/TLSListeners`, `github.com/docker/go-connections/sockets`, `homedir.StickRuntimeDirContents`, `log.G(ctx)`, and `errors.Wrap/Wrapf`. I did not find a narrow control-flow, cleanup, locking, or socket-activation defect that the evidence can support.

No source change was made because an inferred patch would not be pull-request-ready. The expected effect is to avoid shipping a speculative daemon listener change and instead request stronger upstream-report evidence: symbolized goroutine dumps or profiles, complete strace around the alleged churn, and FD targets for the sampled process.

## Git Add Paths
None

## Validation
`DEB_BUILD_OPTIONS=nocheck debian/rules build` failed before compilation: `dh` could not load `Debian/Debhelper/Sequence/golang.pm`, so the workspace lacks the Debian golang debhelper addon.

`go test ./daemon/listeners` failed because `GOCACHE`/`HOME` were unset and module lookup was disabled.

`HOME=/tmp/fixer-home GOCACHE=/tmp/fixer-gocache go test -mod=vendor ./daemon/listeners` failed because this Debian-source layout has inconsistent `go.mod`/`vendor/modules.txt` for direct module-mode testing before Debian’s GOPATH build prep.

Independent reproduction was attempted only to the safe boundary: `pgrep -a dockerd` found no local `dockerd`, the raw investigation files named in `evidence.json` were missing, and no `_build/bin/dockerd` existed after the blocked build. I did not reproduce the failure locally.

## Review Pass 1

RESULT: ok

No source changes are present, and the author correctly treated the evidence as `inferred` rather than forcing a speculative patch. The response names the indirect perf/strace limits, ties the decision to the missing symbolized callsite/raw artifacts, notes the relevant `dockerd` listener helpers and conventions, and reports the project-level build attempt plus exact blockers.