Runaway CPU investigation for dockerd: socket churn at bpf_lsm_file_permission

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. For public upstream review, prepare the final patch against the upstream default integration branch, usually `master` or `main`; use installed or stable source trees for reproduction/backport validation, not as the default merge-request base unless the contribution docs explicitly say to target a stable branch. 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, branch-base choice, 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. If the plan touches authentication, authorization, credentials, cryptography, sandboxing, permissions, or timing/throttling behavior, treat it as security-sensitive: do not plan a source patch unless validation can reproduce the behavior and analyze the security impact; otherwise plan a no-patch diagnosis/report. 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. Security-sensitive areas such as authentication, authorization, credentials, cryptography, sandboxing, permissions, and timing/throttling behavior need reproduced evidence plus explicit security-impact analysis before leaving a source diff; otherwise return a no-patch diagnosis/report for human review. 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.

A previous Fixer patch attempt already exists for this issue. It was generated by Fixer `0.150.0`. Review that patch before changing code, improve it instead of starting blind, and clean up anything awkward or underexplained. In particular, remove avoidable `goto`, tighten the explanation of what the patch is doing, and make the resulting diff feel ready for upstream git review.
- Prior patch: `./prior-best.patch`
- Prior published session: `./prior-best-session.md`

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. For public upstream review, prepare the final patch against the upstream default integration branch, usually `master` or `main`; use installed or stable source trees for reproduction/backport validation, not as the default merge-request base unless the contribution docs explicitly say to target a stable branch. 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, branch-base choice, 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. Security-sensitive source changes touching authentication, authorization, credentials, cryptography, sandboxing, permissions, or timing/throttling behavior require reproduced evidence and explicit security-impact analysis; otherwise list `None` under `## Git Add Paths` and write a no-patch diagnosis/report. 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. For public upstream review, prepare the final patch against the upstream default integration branch, usually `master` or `main`; use installed or stable source trees for reproduction/backport validation, not as the default merge-request base unless the contribution docs explicitly say to target a stable branch. 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, branch-base choice, 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 source patches in security-sensitive areas such as authentication, authorization, credentials, cryptography, sandboxing, permissions, and timing/throttling behavior unless the author reproduced the behavior and explicitly analyzed the security impact of the change; observed-only evidence should become a diagnosis/report, not a PR-ready source diff. 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 captured `dockerd` with low CPU, sleeping state, many futex waits, and a profiler hot path in kernel `bpf_lsm_file_permission`. The bundle labels this as socket churn, but it does not include Go symbols or a reproducible containerd event-stream failure tying the signal to `engine/libcontainerd/remote/client.go`.

## Evidence Confidence
inferred

## Proposed Subject
No source patch: report insufficient evidence for dockerd socket-churn fix

## Patch Plan
Do not edit source in this pass. The prior Fixer patch adding a 100 ms event-stream restart delay should be replaced by a diagnosis/report plan: it changes timing/throttling behavior, and the available evidence does not reproduce the retry loop or analyze security impact.

If stronger evidence is collected later, target upstream `master` for Moby Engine, not a Debian-local workaround. Follow Moby conventions from `engine/CONTRIBUTING.md` and `engine/TESTING.md`: Go changes under `engine/`, `gofmt -s`, unit tests with `gotest.tools/assert`, and existing `containerd/log` logging. Relevant local patterns found include `waitServe` and `libcontainerd/supervisor/remote_daemon.go` timer loops; syscall helpers like `unix_noeintr` and `nlwrap` are not relevant to this gRPC/containerd path.

## Risks
A source patch based only on this evidence would present an inferred timing mitigation as a confirmed bug fix. It could also slow legitimate event-stream recovery or mask a kernel/LSM/containerd issue, since the hot symbol is kernel-side and the trace does not identify the daemon retry code.

## Validation
Before any future source patch, try the workspace-root Debian entrypoint: `dpkg-buildpackage -us -uc -b`. Then use focused engine validation such as `cd engine && TESTDIRS=./libcontainerd/remote TESTFLAGS='-run <new-test>' ./hack/test/unit`.

Bounded independent reproduction attempt: if a local `dockerd` is running, use a short `pgrep -a dockerd` plus `timeout 5 strace -f -tt -p <pid>` sample filtered to futex/socket/containerd IPC calls, and compare it with a controlled containerd event subscription failure. Do not claim `reproduced` unless that command or a focused test actually shows immediate repeated retries.

## Patch Pass

Subject: No source patch: report dockerd socket-churn evidence gap

## Commit Message
No source change is included. The collected `dockerd` evidence points to an indirect socket-churn signal, but it does not reproduce a daemon retry loop or identify Go symbols strongly enough to justify changing timing behavior upstream.

## Evidence Confidence
inferred

## Issue Connection
The likely root cause is not established from the collected data. Fixer observed `/usr/sbin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock` sleeping with many futex waits, 0.1% CPU, and a perf hot path entirely attributed to kernel `bpf_lsm_file_permission`; the bundle labels the profile as socket churn, but the strace excerpt is dominated by futex waits and does not show a reproduced containerd event-subscription retry loop.

The prior Fixer patch throttled `engine/libcontainerd/remote/client.go` event-stream restarts. That is a plausible mitigation path because `processEventStream` can restart after a non-canceled subscription error, but it changes timing/throttling behavior. Under the requested safety bar, that needs reproduced evidence plus security-impact analysis before leaving a source diff. I therefore intentionally made no source changes and replaced the prior patch with this diagnosis.

For a future upstream patch, the target should be Moby Engine `master`, not Debian packaging. Relevant local conventions/helpers reviewed: `engine/CONTRIBUTING.md`, `engine/TESTING.md`, `containerd/log`, `waitServe`, and the timer loop in `libcontainerd/supervisor/remote_daemon.go`; syscall/netlink helpers such as `unix_noeintr` and `nlwrap` do not apply to this gRPC/containerd path.

## Git Add Paths
None

## Validation
- Ran `dpkg-buildpackage -us -uc -b` from the workspace root. It stopped before build/test at `dpkg-checkbuilddeps` due to missing dependencies, including `dh-golang`, `golang-any`, `go-md2man`, many Go library packages, and `gotestsum`.
- Ran `pgrep -a dockerd || true` for the bounded reproduction attempt. It found no local `dockerd`, so a short strace/perf comparison of the collected socket-churn signal was not possible.
- Ran `HOME=/tmp GOCACHE=/tmp/go-build TESTDIRS=./libcontainerd/remote TESTFLAGS='-run TestWaitServe -count=1' ./hack/test/unit` from `engine`. It resolved the package but failed because `gotestsum` is not installed.
- Ran `git diff --exit-code -- .`; workspace has no source diff.

## Review Pass 1

RESULT: ok

No blocking findings.

The author response is a no-patch diagnosis with `## Evidence Confidence` set to `inferred`, which matches the profiler/strace evidence and the security-sensitive timing/throttling constraint. `## Git Add Paths` is `None`, and the workspace has no source diff.

Validation is acceptable for a no-patch report: the workspace-root `dpkg-buildpackage -us -uc -b` entrypoint was attempted and the missing build dependencies were reported; a bounded local `dockerd` reproduction attempt was attempted and blocked by no running daemon; the focused unit entrypoint was attempted and blocked by missing `gotestsum`.

The maintainer-facing explanation correctly rejects the prior timing patch instead of presenting an inferred mitigation as PR-ready, names upstream `master`, and cites relevant Moby conventions/helpers.

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. For public upstream review, prepare the final patch against the upstream default integration branch, usually `master` or `main`; use installed or stable source trees for reproduction/backport validation, not as the default merge-request base unless the contribution docs explicitly say to target a stable branch. 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, branch-base choice, 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. If the plan touches authentication, authorization, credentials, cryptography, sandboxing, permissions, or timing/throttling behavior, treat it as security-sensitive: do not plan a source patch unless validation can reproduce the behavior and analyze the security impact; otherwise plan a no-patch diagnosis/report. 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. Security-sensitive areas such as authentication, authorization, credentials, cryptography, sandboxing, permissions, and timing/throttling behavior need reproduced evidence plus explicit security-impact analysis before leaving a source diff; otherwise return a no-patch diagnosis/report for human review. 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.

A previous Fixer patch attempt already exists for this issue. It was generated by Fixer `0.150.0`. Review that patch before changing code, improve it instead of starting blind, and clean up anything awkward or underexplained. In particular, remove avoidable `goto`, tighten the explanation of what the patch is doing, and make the resulting diff feel ready for upstream git review.
- Prior patch: `./prior-best.patch`
- Prior published session: `./prior-best-session.md`

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. For public upstream review, prepare the final patch against the upstream default integration branch, usually `master` or `main`; use installed or stable source trees for reproduction/backport validation, not as the default merge-request base unless the contribution docs explicitly say to target a stable branch. 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, branch-base choice, 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. Security-sensitive source changes touching authentication, authorization, credentials, cryptography, sandboxing, permissions, or timing/throttling behavior require reproduced evidence and explicit security-impact analysis; otherwise list `None` under `## Git Add Paths` and write a no-patch diagnosis/report. 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. For public upstream review, prepare the final patch against the upstream default integration branch, usually `master` or `main`; use installed or stable source trees for reproduction/backport validation, not as the default merge-request base unless the contribution docs explicitly say to target a stable branch. 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, branch-base choice, 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 source patches in security-sensitive areas such as authentication, authorization, credentials, cryptography, sandboxing, permissions, and timing/throttling behavior unless the author reproduced the behavior and explicitly analyzed the security impact of the change; observed-only evidence should become a diagnosis/report, not a PR-ready source diff. 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 captured `dockerd` with low CPU, sleeping state, many futex waits, and a profiler hot path in kernel `bpf_lsm_file_permission`. The bundle labels this as socket churn, but it does not include Go symbols or a reproducible containerd event-stream failure tying the signal to `engine/libcontainerd/remote/client.go`.

## Evidence Confidence
inferred

## Proposed Subject
No source patch: report insufficient evidence for dockerd socket-churn fix

## Patch Plan
Do not edit source in this pass. The prior Fixer patch adding a 100 ms event-stream restart delay should be replaced by a diagnosis/report plan: it changes timing/throttling behavior, and the available evidence does not reproduce the retry loop or analyze security impact.

If stronger evidence is collected later, target upstream `master` for Moby Engine, not a Debian-local workaround. Follow Moby conventions from `engine/CONTRIBUTING.md` and `engine/TESTING.md`: Go changes under `engine/`, `gofmt -s`, unit tests with `gotest.tools/assert`, and existing `containerd/log` logging. Relevant local patterns found include `waitServe` and `libcontainerd/supervisor/remote_daemon.go` timer loops; syscall helpers like `unix_noeintr` and `nlwrap` are not relevant to this gRPC/containerd path.

## Risks
A source patch based only on this evidence would present an inferred timing mitigation as a confirmed bug fix. It could also slow legitimate event-stream recovery or mask a kernel/LSM/containerd issue, since the hot symbol is kernel-side and the trace does not identify the daemon retry code.

## Validation
Before any future source patch, try the workspace-root Debian entrypoint: `dpkg-buildpackage -us -uc -b`. Then use focused engine validation such as `cd engine && TESTDIRS=./libcontainerd/remote TESTFLAGS='-run <new-test>' ./hack/test/unit`.

Bounded independent reproduction attempt: if a local `dockerd` is running, use a short `pgrep -a dockerd` plus `timeout 5 strace -f -tt -p <pid>` sample filtered to futex/socket/containerd IPC calls, and compare it with a controlled containerd event subscription failure. Do not claim `reproduced` unless that command or a focused test actually shows immediate repeated retries.

## Patch Pass

Subject: No source patch: report dockerd socket-churn evidence gap

## Commit Message
No source change is included. The collected `dockerd` evidence points to an indirect socket-churn signal, but it does not reproduce a daemon retry loop or identify Go symbols strongly enough to justify changing timing behavior upstream.

## Evidence Confidence
inferred

## Issue Connection
The likely root cause is not established from the collected data. Fixer observed `/usr/sbin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock` sleeping with many futex waits, 0.1% CPU, and a perf hot path entirely attributed to kernel `bpf_lsm_file_permission`; the bundle labels the profile as socket churn, but the strace excerpt is dominated by futex waits and does not show a reproduced containerd event-subscription retry loop.

The prior Fixer patch throttled `engine/libcontainerd/remote/client.go` event-stream restarts. That is a plausible mitigation path because `processEventStream` can restart after a non-canceled subscription error, but it changes timing/throttling behavior. Under the requested safety bar, that needs reproduced evidence plus security-impact analysis before leaving a source diff. I therefore intentionally made no source changes and replaced the prior patch with this diagnosis.

For a future upstream patch, the target should be Moby Engine `master`, not Debian packaging. Relevant local conventions/helpers reviewed: `engine/CONTRIBUTING.md`, `engine/TESTING.md`, `containerd/log`, `waitServe`, and the timer loop in `libcontainerd/supervisor/remote_daemon.go`; syscall/netlink helpers such as `unix_noeintr` and `nlwrap` do not apply to this gRPC/containerd path.

## Git Add Paths
None

## Validation
- Ran `dpkg-buildpackage -us -uc -b` from the workspace root. It stopped before build/test at `dpkg-checkbuilddeps` due to missing dependencies, including `dh-golang`, `golang-any`, `go-md2man`, many Go library packages, and `gotestsum`.
- Ran `pgrep -a dockerd || true` for the bounded reproduction attempt. It found no local `dockerd`, so a short strace/perf comparison of the collected socket-churn signal was not possible.
- Ran `HOME=/tmp GOCACHE=/tmp/go-build TESTDIRS=./libcontainerd/remote TESTFLAGS='-run TestWaitServe -count=1' ./hack/test/unit` from `engine`. It resolved the package but failed because `gotestsum` is not installed.
- Ran `git diff --exit-code -- .`; workspace has no source diff.

## Review Pass 1

RESULT: ok

No blocking findings.

The author response is a no-patch diagnosis with `## Evidence Confidence` set to `inferred`, which matches the profiler/strace evidence and the security-sensitive timing/throttling constraint. `## Git Add Paths` is `None`, and the workspace has no source diff.

Validation is acceptable for a no-patch report: the workspace-root `dpkg-buildpackage -us -uc -b` entrypoint was attempted and the missing build dependencies were reported; a bounded local `dockerd` reproduction attempt was attempted and blocked by no running daemon; the focused unit entrypoint was attempted and blocked by missing `gotestsum`.

The maintainer-facing explanation correctly rejects the prior timing patch instead of presenting an inferred mitigation as PR-ready, names upstream `master`, and cites relevant Moby conventions/helpers.

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. For public upstream review, prepare the final patch against the upstream default integration branch, usually `master` or `main`; use installed or stable source trees for reproduction/backport validation, not as the default merge-request base unless the contribution docs explicitly say to target a stable branch. 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, branch-base choice, 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. If the plan touches authentication, authorization, credentials, cryptography, sandboxing, permissions, or timing/throttling behavior, treat it as security-sensitive: do not plan a source patch unless validation can reproduce the behavior and analyze the security impact; otherwise plan a no-patch diagnosis/report. 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. Security-sensitive areas such as authentication, authorization, credentials, cryptography, sandboxing, permissions, and timing/throttling behavior need reproduced evidence plus explicit security-impact analysis before leaving a source diff; otherwise return a no-patch diagnosis/report for human review. 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.

A previous Fixer patch attempt already exists for this issue. It was generated by Fixer `0.150.0`. Review that patch before changing code, improve it instead of starting blind, and clean up anything awkward or underexplained. In particular, remove avoidable `goto`, tighten the explanation of what the patch is doing, and make the resulting diff feel ready for upstream git review.
- Prior patch: `./prior-best.patch`
- Prior published session: `./prior-best-session.md`

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. For public upstream review, prepare the final patch against the upstream default integration branch, usually `master` or `main`; use installed or stable source trees for reproduction/backport validation, not as the default merge-request base unless the contribution docs explicitly say to target a stable branch. 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, branch-base choice, 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. Security-sensitive source changes touching authentication, authorization, credentials, cryptography, sandboxing, permissions, or timing/throttling behavior require reproduced evidence and explicit security-impact analysis; otherwise list `None` under `## Git Add Paths` and write a no-patch diagnosis/report. 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. For public upstream review, prepare the final patch against the upstream default integration branch, usually `master` or `main`; use installed or stable source trees for reproduction/backport validation, not as the default merge-request base unless the contribution docs explicitly say to target a stable branch. 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, branch-base choice, 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 source patches in security-sensitive areas such as authentication, authorization, credentials, cryptography, sandboxing, permissions, and timing/throttling behavior unless the author reproduced the behavior and explicitly analyzed the security impact of the change; observed-only evidence should become a diagnosis/report, not a PR-ready source diff. 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 low CPU, many futex waits, a profiler label of `socket-churn`, and kernel hot symbol `bpf_lsm_file_permission`. The embedded evidence does not include Go symbols or a user-visible failure, and the referenced raw strace/proc artifacts are unavailable locally.

## Evidence Confidence
inferred

## Proposed Subject
No source patch: gather event-stream retry evidence before throttling

## Patch Plan
Do not plan a source patch yet. The prior Fixer patch added a 100 ms throttle in `engine/libcontainerd/remote/client.go` around containerd event stream restarts. That is plausible, but it changes timing/throttling behavior and is not PR-ready without reproducing the behavior and analyzing impact.

Report the likely investigation target instead: `processEventStream` can restart after `EventService().Subscribe` errors once `waitServe` reports containerd ready. If stronger evidence confirms this path, replace recursive goroutine restart with a bounded same-goroutine loop, no avoidable `goto`, following existing `containerd/log` logging and timer patterns.

Contribution docs checked: `engine/CONTRIBUTING.md`, `engine/docs/contributing/README.md`, `engine/TESTING.md`. Current branch is `master`, matching the upstream-style integration target. Local helpers checked include `daemon/listeners.Init`, systemd activation helpers, `sockets.NewUnixSocket/NewTCPSocket`, and `containerd/log`; no relevant generic socket-retry helper was found.

## Risks
A throttling patch could delay legitimate containerd event stream recovery and affect daemon/container state propagation. The current evidence is profiler-only/indirect for this code path, so presenting the prior patch as a confirmed fix would overstate causality.

## Validation
First try the workspace-root build/test entrypoint: `dpkg-buildpackage -us -uc -b`.

Before editing, run a bounded reproduction attempt: create or run a focused `engine/libcontainerd/remote` test/fake that makes `Subscribe` repeatedly return non-canceled errors while `IsServing` returns true, and verify whether current code retries immediately. If local dockerd/containerd is available, also run a short strace/perf comparison around the event-stream failure path. Only after that should a source patch be planned.

## Patch Pass

Subject: no source patch: investigate dockerd socket churn

## Commit Message
No source patch is proposed. Fixer’s evidence points at a possible `dockerd` retry/churn condition, but the available data is profiler and proc sampling without Go stack symbols or a reproduced failing path. The prior patch changed retry timing in the containerd event stream, so it should not be carried forward without reproduced evidence and security-impact review.

## Evidence Confidence
inferred

## Issue Connection
Fixer observed `dockerd` running as `/usr/sbin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock`. The collected signal showed a sleeping process, many futex waits, a `socket-churn` classification, and kernel time under `bpf_lsm_file_permission`; it did not include a concrete user-visible failure or Go-symbol backtrace.

The plausible code-level lead is `engine/libcontainerd/remote/client.go`: `processEventStream` subscribes to containerd task events, and after a non-canceled subscription error it waits for containerd readiness and immediately starts another event-stream goroutine. That could explain retry churn if subscription failures repeat while readiness succeeds, but the evidence does not prove that path.

I reviewed the prior Fixer patch, which replaced the immediate restart with a 100 ms delay and same-goroutine loop. It is directionally reasonable and avoids awkward control flow, but it changes timing/throttling behavior. Under the security-sensitive rule, that requires reproduced evidence and explicit impact analysis before leaving a source diff. I therefore made no source changes. The expected effect is to avoid shipping an unproven timing change while leaving a clear upstream investigation target.

Checked conventions: `engine/CONTRIBUTING.md` requires focused tests and `gofmt -s`; `engine/TESTING.md` names `make test-unit`/`hack/test/unit`. Current branch is `master`, which matches the upstream-style integration base. Relevant local helpers/patterns found were `containerd/log`, `daemon/listeners.Init`, systemd activation helpers, and `sockets.NewUnixSocket/NewTCPSocket`; no local event-stream retry helper was found.

## Git Add Paths
None

## Validation
- `dpkg-buildpackage -us -uc -b` from workspace root failed before build/test because build dependencies are missing, starting with `dh-golang`, `golang-any`, `go-md2man`, `gotestsum`, and many Go library packages.
- `cd engine && HOME=/tmp GOCACHE=/tmp/go-build TESTDIRS=./libcontainerd/remote TESTFLAGS='-run TestProcessEventStream -count=1' ./hack/test/unit` failed because `gotestsum` is not installed.
- `cd engine && HOME=/tmp GOCACHE=/tmp/go-build go test -tags 'netgo journald' ./libcontainerd/remote -run TestProcessEventStream -count=1` failed because dependencies are unavailable in module readonly mode.
- Independent reproduction attempt: `pgrep -a dockerd || true` found no local `dockerd`, so no live strace/perf comparison was possible.
- The raw artifact paths referenced by `evidence.json` for strace, fd targets, and gdb backtrace are missing locally.
- `git diff --exit-code -- .` passed; no source changes were left in the workspace.

## Review Pass 1

RESULT: ok

No blocking findings.

The workspace has no source diff, and `## Git Add Paths` correctly lists `None`. The author keeps `## Evidence Confidence` at `inferred`, avoids carrying forward the prior timing/throttling patch without reproduced evidence, and explains why the prior patch is only a plausible investigation target rather than PR-ready.

Validation is acceptable for a no-patch diagnosis: the workspace-root `dpkg-buildpackage -us -uc -b` was attempted first with the dependency blocker reported, narrower tests were attempted with concrete blockers, and the independent reproduction attempt was bounded and clearly blocked by the lack of a local `dockerd` and missing raw artifacts.

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. For public upstream review, prepare the final patch against the upstream default integration branch, usually `master` or `main`; use installed or stable source trees for reproduction/backport validation, not as the default merge-request base unless the contribution docs explicitly say to target a stable branch. 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, branch-base choice, 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. If the plan touches authentication, authorization, credentials, cryptography, sandboxing, permissions, or timing/throttling behavior, treat it as security-sensitive: do not plan a source patch unless validation can reproduce the behavior and analyze the security impact; otherwise plan a no-patch diagnosis/report. 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. Security-sensitive areas such as authentication, authorization, credentials, cryptography, sandboxing, permissions, and timing/throttling behavior need reproduced evidence plus explicit security-impact analysis before leaving a source diff; otherwise return a no-patch diagnosis/report for human review. 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.

A previous Fixer patch attempt already exists for this issue. It was generated by Fixer `0.150.0`. Review that patch before changing code, improve it instead of starting blind, and clean up anything awkward or underexplained. In particular, remove avoidable `goto`, tighten the explanation of what the patch is doing, and make the resulting diff feel ready for upstream git review.
- Prior patch: `./prior-best.patch`
- Prior published session: `./prior-best-session.md`

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. For public upstream review, prepare the final patch against the upstream default integration branch, usually `master` or `main`; use installed or stable source trees for reproduction/backport validation, not as the default merge-request base unless the contribution docs explicitly say to target a stable branch. 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, branch-base choice, 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. Security-sensitive source changes touching authentication, authorization, credentials, cryptography, sandboxing, permissions, or timing/throttling behavior require reproduced evidence and explicit security-impact analysis; otherwise list `None` under `## Git Add Paths` and write a no-patch diagnosis/report. 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. For public upstream review, prepare the final patch against the upstream default integration branch, usually `master` or `main`; use installed or stable source trees for reproduction/backport validation, not as the default merge-request base unless the contribution docs explicitly say to target a stable branch. 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, branch-base choice, 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 source patches in security-sensitive areas such as authentication, authorization, credentials, cryptography, sandboxing, permissions, and timing/throttling behavior unless the author reproduced the behavior and explicitly analyzed the security impact of the change; observed-only evidence should become a diagnosis/report, not a PR-ready source diff. 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 low CPU, many futex waits, a profiler label of `socket-churn`, and kernel hot symbol `bpf_lsm_file_permission`. The embedded evidence does not include Go symbols or a user-visible failure, and the referenced raw strace/proc artifacts are unavailable locally.

## Evidence Confidence
inferred

## Proposed Subject
No source patch: gather event-stream retry evidence before throttling

## Patch Plan
Do not plan a source patch yet. The prior Fixer patch added a 100 ms throttle in `engine/libcontainerd/remote/client.go` around containerd event stream restarts. That is plausible, but it changes timing/throttling behavior and is not PR-ready without reproducing the behavior and analyzing impact.

Report the likely investigation target instead: `processEventStream` can restart after `EventService().Subscribe` errors once `waitServe` reports containerd ready. If stronger evidence confirms this path, replace recursive goroutine restart with a bounded same-goroutine loop, no avoidable `goto`, following existing `containerd/log` logging and timer patterns.

Contribution docs checked: `engine/CONTRIBUTING.md`, `engine/docs/contributing/README.md`, `engine/TESTING.md`. Current branch is `master`, matching the upstream-style integration target. Local helpers checked include `daemon/listeners.Init`, systemd activation helpers, `sockets.NewUnixSocket/NewTCPSocket`, and `containerd/log`; no relevant generic socket-retry helper was found.

## Risks
A throttling patch could delay legitimate containerd event stream recovery and affect daemon/container state propagation. The current evidence is profiler-only/indirect for this code path, so presenting the prior patch as a confirmed fix would overstate causality.

## Validation
First try the workspace-root build/test entrypoint: `dpkg-buildpackage -us -uc -b`.

Before editing, run a bounded reproduction attempt: create or run a focused `engine/libcontainerd/remote` test/fake that makes `Subscribe` repeatedly return non-canceled errors while `IsServing` returns true, and verify whether current code retries immediately. If local dockerd/containerd is available, also run a short strace/perf comparison around the event-stream failure path. Only after that should a source patch be planned.

## Patch Pass

Subject: no source patch: investigate dockerd socket churn

## Commit Message
No source patch is proposed. Fixer’s evidence points at a possible `dockerd` retry/churn condition, but the available data is profiler and proc sampling without Go stack symbols or a reproduced failing path. The prior patch changed retry timing in the containerd event stream, so it should not be carried forward without reproduced evidence and security-impact review.

## Evidence Confidence
inferred

## Issue Connection
Fixer observed `dockerd` running as `/usr/sbin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock`. The collected signal showed a sleeping process, many futex waits, a `socket-churn` classification, and kernel time under `bpf_lsm_file_permission`; it did not include a concrete user-visible failure or Go-symbol backtrace.

The plausible code-level lead is `engine/libcontainerd/remote/client.go`: `processEventStream` subscribes to containerd task events, and after a non-canceled subscription error it waits for containerd readiness and immediately starts another event-stream goroutine. That could explain retry churn if subscription failures repeat while readiness succeeds, but the evidence does not prove that path.

I reviewed the prior Fixer patch, which replaced the immediate restart with a 100 ms delay and same-goroutine loop. It is directionally reasonable and avoids awkward control flow, but it changes timing/throttling behavior. Under the security-sensitive rule, that requires reproduced evidence and explicit impact analysis before leaving a source diff. I therefore made no source changes. The expected effect is to avoid shipping an unproven timing change while leaving a clear upstream investigation target.

Checked conventions: `engine/CONTRIBUTING.md` requires focused tests and `gofmt -s`; `engine/TESTING.md` names `make test-unit`/`hack/test/unit`. Current branch is `master`, which matches the upstream-style integration base. Relevant local helpers/patterns found were `containerd/log`, `daemon/listeners.Init`, systemd activation helpers, and `sockets.NewUnixSocket/NewTCPSocket`; no local event-stream retry helper was found.

## Git Add Paths
None

## Validation
- `dpkg-buildpackage -us -uc -b` from workspace root failed before build/test because build dependencies are missing, starting with `dh-golang`, `golang-any`, `go-md2man`, `gotestsum`, and many Go library packages.
- `cd engine && HOME=/tmp GOCACHE=/tmp/go-build TESTDIRS=./libcontainerd/remote TESTFLAGS='-run TestProcessEventStream -count=1' ./hack/test/unit` failed because `gotestsum` is not installed.
- `cd engine && HOME=/tmp GOCACHE=/tmp/go-build go test -tags 'netgo journald' ./libcontainerd/remote -run TestProcessEventStream -count=1` failed because dependencies are unavailable in module readonly mode.
- Independent reproduction attempt: `pgrep -a dockerd || true` found no local `dockerd`, so no live strace/perf comparison was possible.
- The raw artifact paths referenced by `evidence.json` for strace, fd targets, and gdb backtrace are missing locally.
- `git diff --exit-code -- .` passed; no source changes were left in the workspace.

## Review Pass 1

RESULT: ok

No blocking findings.

The workspace has no source diff, and `## Git Add Paths` correctly lists `None`. The author keeps `## Evidence Confidence` at `inferred`, avoids carrying forward the prior timing/throttling patch without reproduced evidence, and explains why the prior patch is only a plausible investigation target rather than PR-ready.

Validation is acceptable for a no-patch diagnosis: the workspace-root `dpkg-buildpackage -us -uc -b` was attempted first with the dependency blocker reported, narrower tests were attempted with concrete blockers, and the independent reproduction attempt was bounded and clearly blocked by the lack of a local `dockerd` and missing raw artifacts.

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. For public upstream review, prepare the final patch against the upstream default integration branch, usually `master` or `main`; use installed or stable source trees for reproduction/backport validation, not as the default merge-request base unless the contribution docs explicitly say to target a stable branch. 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, branch-base choice, 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. If the plan touches authentication, authorization, credentials, cryptography, sandboxing, permissions, or timing/throttling behavior, treat it as security-sensitive: do not plan a source patch unless validation can reproduce the behavior and analyze the security impact; otherwise plan a no-patch diagnosis/report. 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. Security-sensitive areas such as authentication, authorization, credentials, cryptography, sandboxing, permissions, and timing/throttling behavior need reproduced evidence plus explicit security-impact analysis before leaving a source diff; otherwise return a no-patch diagnosis/report for human review. 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.

A previous Fixer patch attempt already exists for this issue. It was generated by Fixer `0.150.0`. Review that patch before changing code, improve it instead of starting blind, and clean up anything awkward or underexplained. In particular, remove avoidable `goto`, tighten the explanation of what the patch is doing, and make the resulting diff feel ready for upstream git review.
- Prior patch: `./prior-best.patch`
- Prior published session: `./prior-best-session.md`

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. For public upstream review, prepare the final patch against the upstream default integration branch, usually `master` or `main`; use installed or stable source trees for reproduction/backport validation, not as the default merge-request base unless the contribution docs explicitly say to target a stable branch. 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, branch-base choice, 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. Security-sensitive source changes touching authentication, authorization, credentials, cryptography, sandboxing, permissions, or timing/throttling behavior require reproduced evidence and explicit security-impact analysis; otherwise list `None` under `## Git Add Paths` and write a no-patch diagnosis/report. 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. For public upstream review, prepare the final patch against the upstream default integration branch, usually `master` or `main`; use installed or stable source trees for reproduction/backport validation, not as the default merge-request base unless the contribution docs explicitly say to target a stable branch. 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, branch-base choice, 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 source patches in security-sensitive areas such as authentication, authorization, credentials, cryptography, sandboxing, permissions, and timing/throttling behavior unless the author reproduced the behavior and explicitly analyzed the security impact of the change; observed-only evidence should become a diagnosis/report, not a PR-ready source diff. 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 a running `dockerd` process with 185 threads, many `futex(... FUTEX_WAIT_PRIVATE ...)` waits, two `waitid(P_PIDFD, ...)` waits, 0.1% CPU, and an indirect classifier label of `socket-churn`. The embedded backtrace is stripped, the raw artifacts referenced by `evidence.json` are not present, and the evidence does not identify a specific Docker daemon source path causing churn. This should not be patched as a confirmed Moby bug yet.

## Evidence Confidence

observed

## Proposed Subject

No source patch yet: diagnose `dockerd` idle/wait profile before proposing an upstream change.

## Patch Plan

- Treat the upstream base as Moby `master`: the workspace branch is `master`, and `engine/CONTRIBUTING.md` says PRs must be rebased on `master`.
- Follow Moby conventions from `engine/CONTRIBUTING.md`: Go code under `daemon`/`cmd`, `gofmt -s`, unit tests for changed code, and no new `integration-cli` tests.
- Use local helpers if a later patch is justified: `log.G(ctx)` for logging, `errdefs` for API errors, `daemon/listeners.Init` for listener handling, `github.com/moby/sys/reexec` in tests, and the existing SIGUSR1 stack dump path via `daemon.setupDumpStackTrap` / `pkg/stack`.
- Do not patch `cmd/dockerd`, listener setup, or process waiting based only on the current trace. The evidence shows a mostly sleeping daemon, and the embedded syscall excerpt does not show active socket churn despite the classifier label.
- Improve or replace no prior Fixer patch: I found Debian patch stacks in `.pc/` and `debian/patches`, but no prior Fixer patch tied to finding `90267`.
- If additional evidence identifies a bounded leak or churn source, prefer a small structured change in the implicated package with normal `if`/early-return control flow; avoid awkward `goto` cleanup when a local helper or `defer` gives clearer bounded cleanup.

## Risks

- A speculative patch could change daemon listener, container wait, or shutdown behavior without proving the observed idle profile is harmful.
- Authentication/timing-sensitive listener code exists nearby, including unauthenticated TCP startup delays, but the current evidence uses `-H fd://` and does not justify touching that security-sensitive path.
- The hot kernel symbol `bpf_lsm_file_permission` points outside Moby unless a later trace ties it to a specific daemon file-access loop.

## Validation

- First reproducible project entrypoint from the workspace root: `cd engine && make test-unit`.
- If a later focused source path is identified, run a narrowed unit target with `TESTDIRS='github.com/docker/docker/<package>' TESTFLAGS='-test.run <TestName>' make test-unit`.
- Bounded independent reproduction attempt before any edit: start an isolated debug `dockerd` with temporary `--data-root`, `--exec-root`, `--pidfile`, `-H unix://...`, and the same `--containerd=/run/containerd/containerd.sock` shape when available; then capture `docker info`, thread count, `strace -f -c -p`, and a SIGUSR1 goroutine dump using Moby’s existing stack-dump helper. Only claim reproduced if that run shows the same high-thread idle/futex profile and ties it to a source-level goroutine pattern.

## Patch Pass

Subject: No patch: diagnose dockerd socket churn

## Commit Message
Fixer’s evidence points to a likely retry/churn condition rather than a confirmed source bug: `dockerd` was sleeping with many futex waits, two `waitid(P_PIDFD, ...)` waits, and a profiler classifier labeled the sample as socket churn. The prior patch throttled libcontainerd event-stream retries, but that is a timing/throttling change and the failure was not reproduced locally, so I did not leave a source diff.

## Evidence Confidence
inferred

## Issue Connection
The collected signal is a live `dockerd -H fd:// --containerd=/run/containerd/containerd.sock` sample with 185 threads, mostly futex waits, very low CPU, and an indirect socket-churn classifier. A plausible code-level path exists in `engine/libcontainerd/remote/client.go`: after a non-canceled containerd event subscription error, `processEventStream` can wait for readiness and immediately start a replacement event-stream goroutine.

The prior Fixer patch added a 100 ms delay before resubscribe. I reviewed it and confirmed it is a reasonable targeted mitigation shape, using existing `c.logger`, `waitServe`, and `time.NewTimer` patterns, with no need for new platform wrappers. However, the current instructions classify timing/throttling changes as security-sensitive unless the behavior is reproduced and the impact is analyzed. I could not reproduce the runtime signal locally, so the safe upstream-ready result is no source patch.

The expected next step is to gather a goroutine dump or focused trace from an affected daemon showing repeated containerd event subscription restart before proposing the throttle patch. Upstream base remains Moby `master`, matching `engine/CONTRIBUTING.md`.

## Git Add Paths
None

## Validation
- `cd engine && make test-unit`: blocked by `ERROR: mkdir /root/.docker: read-only file system`.
- `cd engine && HOME=/tmp XDG_CONFIG_HOME=/tmp/.config make test-unit`: blocked by Docker socket permission: `dial unix /var/run/docker.sock: connect: operation not permitted`.
- `cd engine && HOME=/tmp GOCACHE=/tmp/go-build TESTDIRS=./libcontainerd/remote TESTFLAGS='-run TestWaitBeforeEventStreamRestart -count=1' ./hack/test/unit`: blocked by `gotestsum: command not found`.
- `cd engine && HOME=/tmp GOCACHE=/tmp/go-build go test ...`: blocked by missing module resolution in readonly mode.
- `cd engine && HOME=/tmp GOCACHE=/tmp/go-build GOFLAGS=-mod=vendor go test ...`: blocked by inconsistent vendoring in the Debian source checkout.
- `dpkg-buildpackage -us -uc -b`: blocked by unmet build dependencies, starting with `dh-golang`, `golang-any`, `go-md2man`, and `gotestsum`.
- Independent reproduction attempt: `pgrep -a dockerd || true` found no local `dockerd`, so no before/after strace or SIGUSR1 goroutine dump could be collected.

## Review Pass 1

RESULT: ok

No blocking findings.

The workspace has no source diff, and `## Git Add Paths` correctly says `None`. The author response avoids publishing the prior timing/throttling patch without reproduced behavior or security-impact analysis, which matches the review rule for security-sensitive timing changes.

The diagnosis is evidence-scoped: it describes the observed perf/strace signal as indirect, keeps confidence at `inferred`, names the plausible libcontainerd retry path without claiming it as proven, and reports concrete validation blockers from the project-level and focused commands.

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. For public upstream review, prepare the final patch against the upstream default integration branch, usually `master` or `main`; use installed or stable source trees for reproduction/backport validation, not as the default merge-request base unless the contribution docs explicitly say to target a stable branch. 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, branch-base choice, 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. If the plan touches authentication, authorization, credentials, cryptography, sandboxing, permissions, or timing/throttling behavior, treat it as security-sensitive: do not plan a source patch unless validation can reproduce the behavior and analyze the security impact; otherwise plan a no-patch diagnosis/report. 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. Security-sensitive areas such as authentication, authorization, credentials, cryptography, sandboxing, permissions, and timing/throttling behavior need reproduced evidence plus explicit security-impact analysis before leaving a source diff; otherwise return a no-patch diagnosis/report for human review. 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.

A previous Fixer patch attempt already exists for this issue. It was generated by Fixer `0.150.0`. Review that patch before changing code, improve it instead of starting blind, and clean up anything awkward or underexplained. In particular, remove avoidable `goto`, tighten the explanation of what the patch is doing, and make the resulting diff feel ready for upstream git review.
- Prior patch: `./prior-best.patch`
- Prior published session: `./prior-best-session.md`

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. For public upstream review, prepare the final patch against the upstream default integration branch, usually `master` or `main`; use installed or stable source trees for reproduction/backport validation, not as the default merge-request base unless the contribution docs explicitly say to target a stable branch. 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, branch-base choice, 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. Security-sensitive source changes touching authentication, authorization, credentials, cryptography, sandboxing, permissions, or timing/throttling behavior require reproduced evidence and explicit security-impact analysis; otherwise list `None` under `## Git Add Paths` and write a no-patch diagnosis/report. 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. For public upstream review, prepare the final patch against the upstream default integration branch, usually `master` or `main`; use installed or stable source trees for reproduction/backport validation, not as the default merge-request base unless the contribution docs explicitly say to target a stable branch. 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, branch-base choice, 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 source patches in security-sensitive areas such as authentication, authorization, credentials, cryptography, sandboxing, permissions, and timing/throttling behavior unless the author reproduced the behavior and explicitly analyzed the security impact of the change; observed-only evidence should become a diagnosis/report, not a PR-ready source diff. 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 collected indirect `dockerd` evidence for `/usr/sbin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock`: low CPU, sleeping process state, many futex waits, and a perf hot path in kernel `bpf_lsm_file_permission`, with an automated “socket-churn” classification. The evidence does not identify a Go source frame or a concrete user-visible failure. A prior Fixer patch targeted `engine/libcontainerd/remote/client.go` by adding a 100 ms event-stream retry delay, but that changes timing/throttling behavior based on indirect evidence, so it should be replaced by a no-patch diagnosis unless the retry loop is first reproduced.

## Evidence Confidence
inferred

## Proposed Subject
No source patch: diagnose dockerd socket-churn profile before throttling event-stream retries

## Patch Plan
Do not edit source in this pass. Treat this as an upstream Moby issue against `master`, not a Debian-local workaround. The relevant entrypoint is `engine/cmd/dockerd`; nearby conventions use `containerd/log`, `pkg/pidfile`, `homedir`, `daemon/listeners`, and containerd dialer/timer patterns. No dedicated local helper for libcontainerd event-subscription retry throttling was found.

If later evidence reproduces repeated non-canceled `EventService().Subscribe` failures while `IsServing` is true, improve the prior Fixer patch rather than starting blind: keep the retry in one bounded loop, use `time.NewTimer`/context cancellation like nearby `waitServe`, keep `c.logger` logging, and avoid awkward control flow such as `goto` or recursive goroutine spawning. Until then, do not present the delay as a confirmed fix for the collected kernel/strace profile.

## Risks
A source patch would touch timing/throttling behavior and possibly a permission-related kernel hot path, so it is security-sensitive under the instructions. Adding delay without reproduced behavior could mask an unrelated containerd, kernel, LSM/BPF, or systemd socket-activation issue and slow legitimate event-stream recovery.

## Validation
First workspace-root entrypoint to try before any focused checks: `dpkg-buildpackage -us -uc -b`.

Bounded independent reproduction attempt: run a focused libcontainerd test or small harness that forces repeated `Subscribe` errors with `IsServing` true and demonstrates immediate retry behavior before any patch. If that cannot be built, attempt a cheap runtime check such as `pgrep -a dockerd` plus a short `strace`/profile comparison only if a local daemon is safely available. Do not claim `reproduced` unless one of those commands actually shows the retry/churn signal.

## Patch Pass

Subject: Diagnose dockerd socket-churn profile

## Commit Message
No source change was made. The collected data points to a possible retry or wait churn around `dockerd` and its containerd socket, but the evidence is profiler and `/proc` based and does not tie the signal to a reproduced Go code path. The previous retry-throttling patch changes timing behavior, so it is not safe to land without reproducing the suspected event-stream retry loop.

## Evidence Confidence
inferred

## Issue Connection
Fixer observed `dockerd` running as `/usr/sbin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock` with 185 threads, process state `S (sleeping)`, low CPU, many futex waits in `/proc` stack/strace excerpts, and a perf hot path in kernel `bpf_lsm_file_permission`. The likely root cause is some daemon activity repeatedly reaching a file/socket permission path while many goroutines are otherwise parked, but the available evidence does not identify a Go frame or a specific failing operation.

The closest source-level candidate is `engine/libcontainerd/remote/client.go`: after a non-canceled containerd event subscription error, `processEventStream` calls `waitServe`, then immediately starts a replacement event-stream goroutine if containerd reports ready. If subscriptions repeatedly fail while readiness succeeds, that path could churn on the containerd Unix socket. That remains a cautious inference, not a reproduced failure.

I followed `plan-output.txt` and did not apply the prior Fixer patch. That patch adds a 100 ms retry delay, which is a timing/throttling change; under the security-sensitive instruction it needs reproduced evidence plus impact analysis before leaving a source diff. I reviewed Moby’s `engine/CONTRIBUTING.md` and test docs; the upstream base should be `master`. Relevant local conventions are `containerd/log`, existing `time.NewTimer` usage in `waitServe` and `libcontainerd/supervisor`, and daemon helpers such as `pidfile`, `homedir`, and `daemon/listeners`; no dedicated local helper for event-stream retry throttling was found.

Expected effect of this no-patch result is to avoid shipping a speculative timing change and leave an upstream-ready diagnosis: reproduce repeated non-canceled `EventService().Subscribe` failures with `IsServing == true`, then improve the prior patch with a bounded in-goroutine retry loop and no `goto` or recursive goroutine restart.

## Git Add Paths
None

## Validation
- Ran `dpkg-buildpackage -us -uc -b` from the workspace root. It stopped before build/test because build dependencies are missing, starting with `dh-golang`, `golang-any`, `go-md2man`, many Go library packages, and `gotestsum`.
- Attempted focused reproduction/build check: `HOME=/tmp GOCACHE=/tmp/go-build go test -mod=readonly ./libcontainerd/remote -run TestEventStream -count=1` from `engine`. It failed at setup because required Go modules are unavailable in this Debian source checkout with `-mod=readonly`; first missing imports include `github.com/containerd/containerd/api/events` and `github.com/containerd/containerd/v2/client`.
- Attempted cheap runtime reproduction: `pgrep -a dockerd || true`. It returned no local `dockerd`, so no safe local strace/profile comparison was available.
- Checked raw evidence paths referenced by the bundle; `strace.log` and `gdb-bt.txt` were not present under `/var/lib/fixer/investigations/...`, so only the JSON excerpts were available.
- Confirmed no source changes were left: `git diff --stat && git status --short` produced no output.

## Review Pass 1

RESULT: ok

No blocking findings.

The latest response correctly leaves no source diff for an inferred, profiler-only/timing-sensitive issue. `## Evidence Confidence` is valid (`inferred`), `## Git Add Paths` is `None`, and the workspace is clean. The author reviewed the prior retry-throttling patch, rejected it for lack of reproduced evidence, named the relevant Moby conventions/helpers, used `master` as the upstream base, and attempted the project-level `dpkg-buildpackage -us -uc -b` before narrower checks.

The diagnosis is cautious enough for the evidence: it identifies the libcontainerd event-stream restart path as a candidate, but does not present it as a confirmed root cause or PR-ready fix.

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. For public upstream review, prepare the final patch against the upstream default integration branch, usually `master` or `main`; use installed or stable source trees for reproduction/backport validation, not as the default merge-request base unless the contribution docs explicitly say to target a stable branch. 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, branch-base choice, 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. If the plan touches authentication, authorization, credentials, cryptography, sandboxing, permissions, or timing/throttling behavior, treat it as security-sensitive: do not plan a source patch unless validation can reproduce the behavior and analyze the security impact; otherwise plan a no-patch diagnosis/report. 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. Security-sensitive areas such as authentication, authorization, credentials, cryptography, sandboxing, permissions, and timing/throttling behavior need reproduced evidence plus explicit security-impact analysis before leaving a source diff; otherwise return a no-patch diagnosis/report for human review. 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.

A previous Fixer patch attempt already exists for this issue. It was generated by Fixer `0.150.0`. Review that patch before changing code, improve it instead of starting blind, and clean up anything awkward or underexplained. In particular, remove avoidable `goto`, tighten the explanation of what the patch is doing, and make the resulting diff feel ready for upstream git review.
- Prior patch: `./prior-best.patch`
- Prior published session: `./prior-best-session.md`

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. For public upstream review, prepare the final patch against the upstream default integration branch, usually `master` or `main`; use installed or stable source trees for reproduction/backport validation, not as the default merge-request base unless the contribution docs explicitly say to target a stable branch. 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, branch-base choice, 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. Security-sensitive source changes touching authentication, authorization, credentials, cryptography, sandboxing, permissions, or timing/throttling behavior require reproduced evidence and explicit security-impact analysis; otherwise list `None` under `## Git Add Paths` and write a no-patch diagnosis/report. 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. For public upstream review, prepare the final patch against the upstream default integration branch, usually `master` or `main`; use installed or stable source trees for reproduction/backport validation, not as the default merge-request base unless the contribution docs explicitly say to target a stable branch. 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, branch-base choice, 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 source patches in security-sensitive areas such as authentication, authorization, credentials, cryptography, sandboxing, permissions, and timing/throttling behavior unless the author reproduced the behavior and explicitly analyzed the security impact of the change; observed-only evidence should become a diagnosis/report, not a PR-ready source diff. 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 collected indirect `dockerd` evidence for `/usr/sbin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock`: low CPU, sleeping process state, many futex waits, and a perf hot path in kernel `bpf_lsm_file_permission`, with an automated “socket-churn” classification. The evidence does not identify a Go source frame or a concrete user-visible failure. A prior Fixer patch targeted `engine/libcontainerd/remote/client.go` by adding a 100 ms event-stream retry delay, but that changes timing/throttling behavior based on indirect evidence, so it should be replaced by a no-patch diagnosis unless the retry loop is first reproduced.

## Evidence Confidence
inferred

## Proposed Subject
No source patch: diagnose dockerd socket-churn profile before throttling event-stream retries

## Patch Plan
Do not edit source in this pass. Treat this as an upstream Moby issue against `master`, not a Debian-local workaround. The relevant entrypoint is `engine/cmd/dockerd`; nearby conventions use `containerd/log`, `pkg/pidfile`, `homedir`, `daemon/listeners`, and containerd dialer/timer patterns. No dedicated local helper for libcontainerd event-subscription retry throttling was found.

If later evidence reproduces repeated non-canceled `EventService().Subscribe` failures while `IsServing` is true, improve the prior Fixer patch rather than starting blind: keep the retry in one bounded loop, use `time.NewTimer`/context cancellation like nearby `waitServe`, keep `c.logger` logging, and avoid awkward control flow such as `goto` or recursive goroutine spawning. Until then, do not present the delay as a confirmed fix for the collected kernel/strace profile.

## Risks
A source patch would touch timing/throttling behavior and possibly a permission-related kernel hot path, so it is security-sensitive under the instructions. Adding delay without reproduced behavior could mask an unrelated containerd, kernel, LSM/BPF, or systemd socket-activation issue and slow legitimate event-stream recovery.

## Validation
First workspace-root entrypoint to try before any focused checks: `dpkg-buildpackage -us -uc -b`.

Bounded independent reproduction attempt: run a focused libcontainerd test or small harness that forces repeated `Subscribe` errors with `IsServing` true and demonstrates immediate retry behavior before any patch. If that cannot be built, attempt a cheap runtime check such as `pgrep -a dockerd` plus a short `strace`/profile comparison only if a local daemon is safely available. Do not claim `reproduced` unless one of those commands actually shows the retry/churn signal.

## Patch Pass

Subject: Diagnose dockerd socket-churn profile

## Commit Message
No source change was made. The collected data points to a possible retry or wait churn around `dockerd` and its containerd socket, but the evidence is profiler and `/proc` based and does not tie the signal to a reproduced Go code path. The previous retry-throttling patch changes timing behavior, so it is not safe to land without reproducing the suspected event-stream retry loop.

## Evidence Confidence
inferred

## Issue Connection
Fixer observed `dockerd` running as `/usr/sbin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock` with 185 threads, process state `S (sleeping)`, low CPU, many futex waits in `/proc` stack/strace excerpts, and a perf hot path in kernel `bpf_lsm_file_permission`. The likely root cause is some daemon activity repeatedly reaching a file/socket permission path while many goroutines are otherwise parked, but the available evidence does not identify a Go frame or a specific failing operation.

The closest source-level candidate is `engine/libcontainerd/remote/client.go`: after a non-canceled containerd event subscription error, `processEventStream` calls `waitServe`, then immediately starts a replacement event-stream goroutine if containerd reports ready. If subscriptions repeatedly fail while readiness succeeds, that path could churn on the containerd Unix socket. That remains a cautious inference, not a reproduced failure.

I followed `plan-output.txt` and did not apply the prior Fixer patch. That patch adds a 100 ms retry delay, which is a timing/throttling change; under the security-sensitive instruction it needs reproduced evidence plus impact analysis before leaving a source diff. I reviewed Moby’s `engine/CONTRIBUTING.md` and test docs; the upstream base should be `master`. Relevant local conventions are `containerd/log`, existing `time.NewTimer` usage in `waitServe` and `libcontainerd/supervisor`, and daemon helpers such as `pidfile`, `homedir`, and `daemon/listeners`; no dedicated local helper for event-stream retry throttling was found.

Expected effect of this no-patch result is to avoid shipping a speculative timing change and leave an upstream-ready diagnosis: reproduce repeated non-canceled `EventService().Subscribe` failures with `IsServing == true`, then improve the prior patch with a bounded in-goroutine retry loop and no `goto` or recursive goroutine restart.

## Git Add Paths
None

## Validation
- Ran `dpkg-buildpackage -us -uc -b` from the workspace root. It stopped before build/test because build dependencies are missing, starting with `dh-golang`, `golang-any`, `go-md2man`, many Go library packages, and `gotestsum`.
- Attempted focused reproduction/build check: `HOME=/tmp GOCACHE=/tmp/go-build go test -mod=readonly ./libcontainerd/remote -run TestEventStream -count=1` from `engine`. It failed at setup because required Go modules are unavailable in this Debian source checkout with `-mod=readonly`; first missing imports include `github.com/containerd/containerd/api/events` and `github.com/containerd/containerd/v2/client`.
- Attempted cheap runtime reproduction: `pgrep -a dockerd || true`. It returned no local `dockerd`, so no safe local strace/profile comparison was available.
- Checked raw evidence paths referenced by the bundle; `strace.log` and `gdb-bt.txt` were not present under `/var/lib/fixer/investigations/...`, so only the JSON excerpts were available.
- Confirmed no source changes were left: `git diff --stat && git status --short` produced no output.

## Review Pass 1

RESULT: ok

No blocking findings.

The latest response correctly leaves no source diff for an inferred, profiler-only/timing-sensitive issue. `## Evidence Confidence` is valid (`inferred`), `## Git Add Paths` is `None`, and the workspace is clean. The author reviewed the prior retry-throttling patch, rejected it for lack of reproduced evidence, named the relevant Moby conventions/helpers, used `master` as the upstream base, and attempted the project-level `dpkg-buildpackage -us -uc -b` before narrower checks.

The diagnosis is cautious enough for the evidence: it identifies the libcontainerd event-stream restart path as a candidate, but does not present it as a confirmed root cause or PR-ready fix.

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, engine/libcontainerd/remote/client_test.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.

Response

## Plan Pass

## Problem
Fixer observed `dockerd` running as `/usr/sbin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock` with profiler/trace evidence classified as socket churn, plus many futex waits and a kernel `bpf_lsm_file_permission` hot path. In `engine/libcontainerd/remote/client.go`, `processEventStream` can immediately start a replacement event-stream goroutine after a non-canceled `Subscribe` error if `IsServing` reports containerd is ready. That gives a plausible daemon-side retry path that can repeatedly touch the containerd Unix socket without a bounded delay.

## Evidence Confidence
observed

## Proposed Subject
`libcontainerd: throttle event stream restart after subscription errors`

## Patch Plan
- Patch upstream engine code, not Debian packaging.
- Replace the immediate `go c.processEventStream(ctx, ns); return` restart in `engine/libcontainerd/remote/client.go` with cleaner bounded retry control inside the same goroutine.
- Keep the existing `waitServe` readiness check, but add a context-aware delay before resubscribing even when containerd is already serving. Use the local timer pattern already present in `waitServe` and `libcontainerd/supervisor/remote_daemon.go`; avoid `goto` or recursive goroutine restart.
- Preserve current cancellation behavior for `codes.Canceled`, `context.Canceled`, and shutdown, and continue to use `c.logger`/`containerd/log` conventions.
- Add focused unit coverage around the retry decision if practical. Because `containerd.Client` is concrete, this may require extracting a small unexported helper for the restart delay/loop decision rather than mocking the full client.
- No prior Fixer patch is present in the workspace (`git diff` is empty), so there is nothing to replace.
- Local helper scan: `engine/internal/unix_noeintr` and `engine/internal/nlwrap` are syscall/netlink-specific and not relevant to gRPC event subscription; no subsystem-specific socket retry helper was found.

## Risks
- The evidence is profiler/trace-based and does not name Go symbols, so this is a targeted mitigation for an observed retry/churn signal, not a proven root-cause fix.
- Adding delay can slightly slow event-stream recovery after transient containerd event-service failures.
- A too-large delay could delay container lifecycle event processing; keep the delay small and bounded.

## Validation
- From workspace root, first try the package entrypoint: `dpkg-buildpackage -us -uc -b` so Debian configure/build/test wiring is exercised.
- Then run focused engine tests, e.g. `cd engine && TESTDIRS=./libcontainerd/remote TESTFLAGS='-run TestProcessEventStream' ./hack/test/unit` or the nearest buildable equivalent.
- Bounded independent reproduction attempt: add/run a focused test or small instrumented check that simulates repeated non-canceled event subscription errors while readiness is true, and verify pre-patch behavior retries immediately while post-patch behavior enforces the delay. In the final `## Issue Connection`, state that the failure was observed by Fixer and not independently reproduced unless that check demonstrates the failing loop directly.

## Patch Pass

Subject: libcontainerd: throttle event stream restarts

## Commit Message
`dockerd` restarts the containerd task event stream after subscription errors. When containerd is already serving, the old code immediately spawned a replacement goroutine, so repeated transient subscription failures could retry without any pause. Keep the restart in the same goroutine and wait briefly before resubscribing.

## Evidence Confidence
observed

## Issue Connection
Fixer observed `dockerd` running with `--containerd=/run/containerd/containerd.sock`; the collected perf/strace/proc evidence showed a sleeping daemon with many futex waits and classified the profile as socket churn. This failure was observed by Fixer and not independently reproduced.

The cautious code-level connection is the libcontainerd event stream, which is the daemon’s subscription to containerd task events. On a non-canceled subscription error, `processEventStream` waited for containerd readiness and then immediately started another `processEventStream` goroutine. If the readiness probe succeeds while subscriptions keep failing transiently, that path can repeatedly resubscribe to the containerd socket without a bounded delay.

I changed that path to return through a one-shot helper and retry in the same goroutine after a 100 ms context-aware delay. I also added a short comment explaining the invariant: a successful readiness probe must not allow immediate resubscribe churn. The code follows nearby timer patterns and existing `containerd/log` usage; syscall wrappers such as `engine/internal/unix_noeintr` and netlink helpers such as `engine/internal/nlwrap` do not fit this gRPC/containerd subscription path.

The expected effect is to reduce rapid containerd socket retry churn after transient event subscription failures while preserving cancellation and normal restart behavior.

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

## Validation
- Ran `dpkg-buildpackage -us -uc -b` from the workspace root. It did not reach configure/build/test because `dpkg-checkbuilddeps` aborted with unmet build dependencies, starting with `dh-golang`, `golang-any`, `go-md2man`, and including `gotestsum`.
- Ran `HOME=/tmp GOCACHE=/tmp/go-build TESTDIRS=./libcontainerd/remote TESTFLAGS='-run TestWaitEventStreamRestart -count=1' ./hack/test/unit`. Blocked because `gotestsum` is not installed.
- Ran `HOME=/tmp GOCACHE=/tmp/go-build go test -tags 'netgo journald' ./libcontainerd/remote -run TestWaitEventStreamRestart -count=1`. Blocked because required Go dependencies are not available in this Debian source checkout; Go reported `cannot find module providing package ... import lookup disabled by -mod=readonly`.
- Ran `gofmt -w engine/libcontainerd/remote/client.go engine/libcontainerd/remote/client_test.go`.
- Ran `git diff --check`: passed.
- Independent reproduction attempt: `pgrep -a dockerd || true` found no local `dockerd`, so a bounded before/after strace comparison of the collected socket-churn signal was not available.

## Review Pass 1

RESULT: ok

No blocking findings.

`## Git Add Paths` matches the current changed path set exactly: `engine/libcontainerd/remote/client.go` and `engine/libcontainerd/remote/client_test.go`.

The patch keeps the change narrowly scoped, avoids recursive goroutine restart, preserves cancellation behavior, and uses nearby timer/logging conventions. The author response correctly keeps confidence at `observed`, says Fixer observed the signal but did not independently reproduce it, and explains both shipped functional files through the implementation and validation notes. Validation attempted the workspace-root Debian build first and reported the concrete dependency blocker before narrower checks.

Diff

diff --git a/engine/libcontainerd/remote/client.go b/engine/libcontainerd/remote/client.go
index 3d3ec63..c07c000 100644
--- a/engine/libcontainerd/remote/client.go
+++ b/engine/libcontainerd/remote/client.go
@@ -607,6 +607,28 @@ func (c *client) waitServe(ctx context.Context) bool {
 }
 
 func (c *client) processEventStream(ctx context.Context, ns string) {
+	for c.processEventStreamOnce(ctx, ns) {
+		if !waitEventStreamRestart(ctx, eventStreamRestartDelay) {
+			return
+		}
+	}
+}
+
+const eventStreamRestartDelay = 100 * time.Millisecond
+
+func waitEventStreamRestart(ctx context.Context, delay time.Duration) bool {
+	timer := time.NewTimer(delay)
+	defer timer.Stop()
+
+	select {
+	case <-ctx.Done():
+		return false
+	case <-timer.C:
+		return true
+	}
+}
+
+func (c *client) processEventStreamOnce(ctx context.Context, ns string) bool {
 	// 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,
@@ -629,13 +651,15 @@ func (c *client) processEventStream(ctx context.Context, ns string) {
 					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)
-						return
+						// A failed subscription can be followed by an immediate
+						// successful readiness probe. Delay the resubscribe so
+						// transient errors cannot spin on containerd's socket.
+						return true
 					}
 				}
 				c.logger.WithError(ctx.Err()).Info("stopping event stream following graceful shutdown")
 			}
-			return
+			return false
 		case ev := <-eventStream:
 			if ev.Event == nil {
 				c.logger.WithField("event", ev).Warn("invalid event")
diff --git a/engine/libcontainerd/remote/client_test.go b/engine/libcontainerd/remote/client_test.go
new file mode 100644
index 0000000..ee65c80
--- /dev/null
+++ b/engine/libcontainerd/remote/client_test.go
@@ -0,0 +1,26 @@
+package remote
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"gotest.tools/v3/assert"
+)
+
+func TestWaitEventStreamRestartWaitsForDelay(t *testing.T) {
+	const delay = 20 * time.Millisecond
+
+	start := time.Now()
+	assert.Check(t, waitEventStreamRestart(context.Background(), delay))
+	assert.Check(t, time.Since(start) >= delay)
+}
+
+func TestWaitEventStreamRestartStopsOnCancel(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	cancel()
+
+	start := time.Now()
+	assert.Check(t, !waitEventStreamRestart(ctx, time.Hour))
+	assert.Check(t, time.Since(start) < time.Second)
+}

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, engine/libcontainerd/remote/client_test.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.

Response

## Plan Pass

## Problem
Fixer observed `dockerd` running as `/usr/sbin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock` with profiler/trace evidence classified as socket churn, plus many futex waits and a kernel `bpf_lsm_file_permission` hot path. In `engine/libcontainerd/remote/client.go`, `processEventStream` can immediately start a replacement event-stream goroutine after a non-canceled `Subscribe` error if `IsServing` reports containerd is ready. That gives a plausible daemon-side retry path that can repeatedly touch the containerd Unix socket without a bounded delay.

## Evidence Confidence
observed

## Proposed Subject
`libcontainerd: throttle event stream restart after subscription errors`

## Patch Plan
- Patch upstream engine code, not Debian packaging.
- Replace the immediate `go c.processEventStream(ctx, ns); return` restart in `engine/libcontainerd/remote/client.go` with cleaner bounded retry control inside the same goroutine.
- Keep the existing `waitServe` readiness check, but add a context-aware delay before resubscribing even when containerd is already serving. Use the local timer pattern already present in `waitServe` and `libcontainerd/supervisor/remote_daemon.go`; avoid `goto` or recursive goroutine restart.
- Preserve current cancellation behavior for `codes.Canceled`, `context.Canceled`, and shutdown, and continue to use `c.logger`/`containerd/log` conventions.
- Add focused unit coverage around the retry decision if practical. Because `containerd.Client` is concrete, this may require extracting a small unexported helper for the restart delay/loop decision rather than mocking the full client.
- No prior Fixer patch is present in the workspace (`git diff` is empty), so there is nothing to replace.
- Local helper scan: `engine/internal/unix_noeintr` and `engine/internal/nlwrap` are syscall/netlink-specific and not relevant to gRPC event subscription; no subsystem-specific socket retry helper was found.

## Risks
- The evidence is profiler/trace-based and does not name Go symbols, so this is a targeted mitigation for an observed retry/churn signal, not a proven root-cause fix.
- Adding delay can slightly slow event-stream recovery after transient containerd event-service failures.
- A too-large delay could delay container lifecycle event processing; keep the delay small and bounded.

## Validation
- From workspace root, first try the package entrypoint: `dpkg-buildpackage -us -uc -b` so Debian configure/build/test wiring is exercised.
- Then run focused engine tests, e.g. `cd engine && TESTDIRS=./libcontainerd/remote TESTFLAGS='-run TestProcessEventStream' ./hack/test/unit` or the nearest buildable equivalent.
- Bounded independent reproduction attempt: add/run a focused test or small instrumented check that simulates repeated non-canceled event subscription errors while readiness is true, and verify pre-patch behavior retries immediately while post-patch behavior enforces the delay. In the final `## Issue Connection`, state that the failure was observed by Fixer and not independently reproduced unless that check demonstrates the failing loop directly.

## Patch Pass

Subject: libcontainerd: throttle event stream restarts

## Commit Message
`dockerd` restarts the containerd task event stream after subscription errors. When containerd is already serving, the old code immediately spawned a replacement goroutine, so repeated transient subscription failures could retry without any pause. Keep the restart in the same goroutine and wait briefly before resubscribing.

## Evidence Confidence
observed

## Issue Connection
Fixer observed `dockerd` running with `--containerd=/run/containerd/containerd.sock`; the collected perf/strace/proc evidence showed a sleeping daemon with many futex waits and classified the profile as socket churn. This failure was observed by Fixer and not independently reproduced.

The cautious code-level connection is the libcontainerd event stream, which is the daemon’s subscription to containerd task events. On a non-canceled subscription error, `processEventStream` waited for containerd readiness and then immediately started another `processEventStream` goroutine. If the readiness probe succeeds while subscriptions keep failing transiently, that path can repeatedly resubscribe to the containerd socket without a bounded delay.

I changed that path to return through a one-shot helper and retry in the same goroutine after a 100 ms context-aware delay. I also added a short comment explaining the invariant: a successful readiness probe must not allow immediate resubscribe churn. The code follows nearby timer patterns and existing `containerd/log` usage; syscall wrappers such as `engine/internal/unix_noeintr` and netlink helpers such as `engine/internal/nlwrap` do not fit this gRPC/containerd subscription path.

The expected effect is to reduce rapid containerd socket retry churn after transient event subscription failures while preserving cancellation and normal restart behavior.

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

## Validation
- Ran `dpkg-buildpackage -us -uc -b` from the workspace root. It did not reach configure/build/test because `dpkg-checkbuilddeps` aborted with unmet build dependencies, starting with `dh-golang`, `golang-any`, `go-md2man`, and including `gotestsum`.
- Ran `HOME=/tmp GOCACHE=/tmp/go-build TESTDIRS=./libcontainerd/remote TESTFLAGS='-run TestWaitEventStreamRestart -count=1' ./hack/test/unit`. Blocked because `gotestsum` is not installed.
- Ran `HOME=/tmp GOCACHE=/tmp/go-build go test -tags 'netgo journald' ./libcontainerd/remote -run TestWaitEventStreamRestart -count=1`. Blocked because required Go dependencies are not available in this Debian source checkout; Go reported `cannot find module providing package ... import lookup disabled by -mod=readonly`.
- Ran `gofmt -w engine/libcontainerd/remote/client.go engine/libcontainerd/remote/client_test.go`.
- Ran `git diff --check`: passed.
- Independent reproduction attempt: `pgrep -a dockerd || true` found no local `dockerd`, so a bounded before/after strace comparison of the collected socket-churn signal was not available.

## Review Pass 1

RESULT: ok

No blocking findings.

`## Git Add Paths` matches the current changed path set exactly: `engine/libcontainerd/remote/client.go` and `engine/libcontainerd/remote/client_test.go`.

The patch keeps the change narrowly scoped, avoids recursive goroutine restart, preserves cancellation behavior, and uses nearby timer/logging conventions. The author response correctly keeps confidence at `observed`, says Fixer observed the signal but did not independently reproduce it, and explains both shipped functional files through the implementation and validation notes. Validation attempted the workspace-root Debian build first and reported the concrete dependency blocker before narrower checks.

Diff

diff --git a/engine/libcontainerd/remote/client.go b/engine/libcontainerd/remote/client.go
index 3d3ec63..c07c000 100644
--- a/engine/libcontainerd/remote/client.go
+++ b/engine/libcontainerd/remote/client.go
@@ -607,6 +607,28 @@ func (c *client) waitServe(ctx context.Context) bool {
 }
 
 func (c *client) processEventStream(ctx context.Context, ns string) {
+	for c.processEventStreamOnce(ctx, ns) {
+		if !waitEventStreamRestart(ctx, eventStreamRestartDelay) {
+			return
+		}
+	}
+}
+
+const eventStreamRestartDelay = 100 * time.Millisecond
+
+func waitEventStreamRestart(ctx context.Context, delay time.Duration) bool {
+	timer := time.NewTimer(delay)
+	defer timer.Stop()
+
+	select {
+	case <-ctx.Done():
+		return false
+	case <-timer.C:
+		return true
+	}
+}
+
+func (c *client) processEventStreamOnce(ctx context.Context, ns string) bool {
 	// 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,
@@ -629,13 +651,15 @@ func (c *client) processEventStream(ctx context.Context, ns string) {
 					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)
-						return
+						// A failed subscription can be followed by an immediate
+						// successful readiness probe. Delay the resubscribe so
+						// transient errors cannot spin on containerd's socket.
+						return true
 					}
 				}
 				c.logger.WithError(ctx.Err()).Info("stopping event stream following graceful shutdown")
 			}
-			return
+			return false
 		case ev := <-eventStream:
 			if ev.Event == nil {
 				c.logger.WithField("event", ev).Warn("invalid event")
diff --git a/engine/libcontainerd/remote/client_test.go b/engine/libcontainerd/remote/client_test.go
new file mode 100644
index 0000000..ee65c80
--- /dev/null
+++ b/engine/libcontainerd/remote/client_test.go
@@ -0,0 +1,26 @@
+package remote
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"gotest.tools/v3/assert"
+)
+
+func TestWaitEventStreamRestartWaitsForDelay(t *testing.T) {
+	const delay = 20 * time.Millisecond
+
+	start := time.Now()
+	assert.Check(t, waitEventStreamRestart(context.Background(), delay))
+	assert.Check(t, time.Since(start) >= delay)
+}
+
+func TestWaitEventStreamRestartStopsOnCancel(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	cancel()
+
+	start := time.Now()
+	assert.Check(t, !waitEventStreamRestart(ctx, time.Hour))
+	assert.Check(t, time.Since(start) < time.Second)
+}

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 3-second perf profile attributing the sampled hot path to kernel `bpf_lsm_file_permission`, while the process itself was sleeping with about `0.1%` CPU. Embedded `strace` and stack excerpts are dominated by `futex` waits, not a confirmed tight userspace loop. The raw artifact files referenced by the bundle are not present in the workspace, and the stripped backtrace does not map to Go symbols.

## Evidence Confidence
inferred

## Proposed Subject
No source patch yet: diagnose the `dockerd` profiler signal as insufficient for an upstream Moby change until an independent low-cost signal ties `bpf_lsm_file_permission` activity to a specific daemon code path.

## Patch Plan
1. Do not edit files on the current evidence alone. The evidence is profiler-only/indirect, low-CPU, kernel-attributed, and does not identify a Docker source function.
2. Improve or replace any prior Fixer attempt that treats this as confirmed socket churn; the embedded `strace` excerpts show `futex`/`waitid`, and the raw strace is unavailable.
3. If more evidence is collected, start from the `dockerd` entrypoint in `engine/cmd/dockerd/docker.go` and daemon setup in `engine/cmd/dockerd/daemon.go`, only then inspect runtime/containerd paths if the new evidence points there.
4. Follow Moby conventions from `engine/CONTRIBUTING.md` and `engine/TESTING.md`: Go changes under `cmd/dockerd` or `daemon`, unit tests for bug fixes, `gofmt -s -w`, and clear maintainer-facing commit text.
5. Prefer local conventions/helpers if a patch becomes justified: `log.G(ctx)` for logging, `daemon/internal/filedescriptors.GetTotalUsedFds` for daemon FD counting, `engine/pkg/system` compatibility helpers where applicable, and existing Cobra/config patterns in `cmd/dockerd`. Reject awkward control flow such as avoidable `goto`; use bounded helper functions or early returns.

## Risks
A source patch from this evidence would likely be speculative. The observed hot symbol is in the kernel LSM path, the sampled package list implicates the kernel image, CPU use is low, and no daemon API request, file path, fd target, or Go symbol is available to connect the cost to Moby code.

## Validation
If later evidence supports a source change, first try the reproducible project entrypoint from the workspace root: `cd engine && make test-unit TESTDIRS=./cmd/dockerd ./daemon`. Then run the focused package test for any touched package.

Bounded independent reproduction attempt before editing: run a local `dockerd` smoke/profile only if safe in the environment, e.g. `dockerd --validate --config-file <minimal-valid-config>` for config-path changes, or a short `perf`/`strace` sample of a locally started test daemon while issuing the suspected API call. Do not claim reproduced unless that command actually shows repeated `bpf_lsm_file_permission` or the specific syscall pattern tied to the candidate code path.

## Patch Pass

Subject: No patch: diagnose dockerd LSM perf sample

## Commit Message
No source change is included. The collected evidence points to a kernel-side Linux Security Module hook sample, not to a confirmed `dockerd` userspace loop or a source-level Moby bug.

## Evidence Confidence
inferred

## Issue Connection
The collected signal is a 3-second profile of `/usr/sbin/dockerd` where perf attributed samples to kernel `bpf_lsm_file_permission`, while `/proc` evidence showed the daemon sleeping at about `0.1%` CPU. The embedded strace excerpt is dominated by `futex` waits and `waitid`, and the kernel stack excerpt is a futex wait path, so the evidence does not support the bundle’s higher-level “socket-churn” label as a confirmed userspace loop.

The cautious inference is that perf sampled a kernel file-permission hook while the daemon was mostly idle. The raw artifact paths referenced by the bundle are absent from this workspace, and the bundled backtraces are stripped, so I could not connect the sample to a Go function or a daemon request path.

I followed the saved plan and did not leave a source diff. I inspected the `dockerd` entrypoint and daemon setup, plus the nearby daemon helper most plausibly related to file-permission checks: `daemon/internal/filedescriptors.GetTotalUsedFds`. The current source already uses a Linux 6.2+ `stat` fast path before falling back to opening `/proc/<pid>/fd`, and there is no evidence that repeated `/info` requests or this helper produced the observed sample. Local conventions found were `log.G(ctx)` for logging, `daemon/internal/filedescriptors.GetTotalUsedFds` for daemon FD counting, `engine/pkg/system` compatibility helpers where applicable, and the existing Cobra/config patterns in `cmd/dockerd`.

No code change was made, so there is no runtime effect. The expected effect of this report is to avoid an upstream patch based on indirect profiler evidence until a new trace ties `bpf_lsm_file_permission` activity to a specific Moby code path.

## Git Add Paths
None

## Validation
`timeout 60s debian/rules override_dh_auto_test` failed from the workspace root because the prepared tree has no built binaries: `_build/bin/docker: No such file or directory`.

`go test -mod=vendor ./daemon/internal/filedescriptors` failed because Debian’s split source has inconsistent module/vendor metadata for direct module-mode testing.

Independent reproduction attempt: `timeout 10s perf record -g -o /tmp/fixer-dockerd-validate.perf.data -- /usr/sbin/dockerd --validate --config-file /dev/null` was blocked by kernel perf permissions: `perf_event_paranoid setting is 3` and perf could not open any events.

Raw artifact check confirmed the referenced `strace.log` and `fd-targets.txt` paths are not present. `git status --short` remained clean.

## Review Pass 1

RESULT: ok

No blocking findings.

The first pass leaves no source diff, which matches the indirect evidence level. The author correctly classifies confidence as `inferred`, avoids inventing a reproduced failure, and reports the project-level validation attempt with its exact blocker. The maintainer-facing explanation ties the perf `bpf_lsm_file_permission` sample, sleeping/futex evidence, and missing raw artifacts to the decision not to patch. The report also names relevant local conventions/helpers (`log.G(ctx)`, `daemon/internal/filedescriptors.GetTotalUsedFds`, `engine/pkg/system`, Cobra/config patterns) and the workspace is clean.

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 3-second perf profile attributing the sampled hot path to kernel `bpf_lsm_file_permission`, while the process itself was sleeping with about `0.1%` CPU. Embedded `strace` and stack excerpts are dominated by `futex` waits, not a confirmed tight userspace loop. The raw artifact files referenced by the bundle are not present in the workspace, and the stripped backtrace does not map to Go symbols.

## Evidence Confidence
inferred

## Proposed Subject
No source patch yet: diagnose the `dockerd` profiler signal as insufficient for an upstream Moby change until an independent low-cost signal ties `bpf_lsm_file_permission` activity to a specific daemon code path.

## Patch Plan
1. Do not edit files on the current evidence alone. The evidence is profiler-only/indirect, low-CPU, kernel-attributed, and does not identify a Docker source function.
2. Improve or replace any prior Fixer attempt that treats this as confirmed socket churn; the embedded `strace` excerpts show `futex`/`waitid`, and the raw strace is unavailable.
3. If more evidence is collected, start from the `dockerd` entrypoint in `engine/cmd/dockerd/docker.go` and daemon setup in `engine/cmd/dockerd/daemon.go`, only then inspect runtime/containerd paths if the new evidence points there.
4. Follow Moby conventions from `engine/CONTRIBUTING.md` and `engine/TESTING.md`: Go changes under `cmd/dockerd` or `daemon`, unit tests for bug fixes, `gofmt -s -w`, and clear maintainer-facing commit text.
5. Prefer local conventions/helpers if a patch becomes justified: `log.G(ctx)` for logging, `daemon/internal/filedescriptors.GetTotalUsedFds` for daemon FD counting, `engine/pkg/system` compatibility helpers where applicable, and existing Cobra/config patterns in `cmd/dockerd`. Reject awkward control flow such as avoidable `goto`; use bounded helper functions or early returns.

## Risks
A source patch from this evidence would likely be speculative. The observed hot symbol is in the kernel LSM path, the sampled package list implicates the kernel image, CPU use is low, and no daemon API request, file path, fd target, or Go symbol is available to connect the cost to Moby code.

## Validation
If later evidence supports a source change, first try the reproducible project entrypoint from the workspace root: `cd engine && make test-unit TESTDIRS=./cmd/dockerd ./daemon`. Then run the focused package test for any touched package.

Bounded independent reproduction attempt before editing: run a local `dockerd` smoke/profile only if safe in the environment, e.g. `dockerd --validate --config-file <minimal-valid-config>` for config-path changes, or a short `perf`/`strace` sample of a locally started test daemon while issuing the suspected API call. Do not claim reproduced unless that command actually shows repeated `bpf_lsm_file_permission` or the specific syscall pattern tied to the candidate code path.

## Patch Pass

Subject: No patch: diagnose dockerd LSM perf sample

## Commit Message
No source change is included. The collected evidence points to a kernel-side Linux Security Module hook sample, not to a confirmed `dockerd` userspace loop or a source-level Moby bug.

## Evidence Confidence
inferred

## Issue Connection
The collected signal is a 3-second profile of `/usr/sbin/dockerd` where perf attributed samples to kernel `bpf_lsm_file_permission`, while `/proc` evidence showed the daemon sleeping at about `0.1%` CPU. The embedded strace excerpt is dominated by `futex` waits and `waitid`, and the kernel stack excerpt is a futex wait path, so the evidence does not support the bundle’s higher-level “socket-churn” label as a confirmed userspace loop.

The cautious inference is that perf sampled a kernel file-permission hook while the daemon was mostly idle. The raw artifact paths referenced by the bundle are absent from this workspace, and the bundled backtraces are stripped, so I could not connect the sample to a Go function or a daemon request path.

I followed the saved plan and did not leave a source diff. I inspected the `dockerd` entrypoint and daemon setup, plus the nearby daemon helper most plausibly related to file-permission checks: `daemon/internal/filedescriptors.GetTotalUsedFds`. The current source already uses a Linux 6.2+ `stat` fast path before falling back to opening `/proc/<pid>/fd`, and there is no evidence that repeated `/info` requests or this helper produced the observed sample. Local conventions found were `log.G(ctx)` for logging, `daemon/internal/filedescriptors.GetTotalUsedFds` for daemon FD counting, `engine/pkg/system` compatibility helpers where applicable, and the existing Cobra/config patterns in `cmd/dockerd`.

No code change was made, so there is no runtime effect. The expected effect of this report is to avoid an upstream patch based on indirect profiler evidence until a new trace ties `bpf_lsm_file_permission` activity to a specific Moby code path.

## Git Add Paths
None

## Validation
`timeout 60s debian/rules override_dh_auto_test` failed from the workspace root because the prepared tree has no built binaries: `_build/bin/docker: No such file or directory`.

`go test -mod=vendor ./daemon/internal/filedescriptors` failed because Debian’s split source has inconsistent module/vendor metadata for direct module-mode testing.

Independent reproduction attempt: `timeout 10s perf record -g -o /tmp/fixer-dockerd-validate.perf.data -- /usr/sbin/dockerd --validate --config-file /dev/null` was blocked by kernel perf permissions: `perf_event_paranoid setting is 3` and perf could not open any events.

Raw artifact check confirmed the referenced `strace.log` and `fd-targets.txt` paths are not present. `git status --short` remained clean.

## Review Pass 1

RESULT: ok

No blocking findings.

The first pass leaves no source diff, which matches the indirect evidence level. The author correctly classifies confidence as `inferred`, avoids inventing a reproduced failure, and reports the project-level validation attempt with its exact blocker. The maintainer-facing explanation ties the perf `bpf_lsm_file_permission` sample, sleeping/futex evidence, and missing raw artifacts to the decision not to patch. The report also names relevant local conventions/helpers (`log.G(ctx)`, `daemon/internal/filedescriptors.GetTotalUsedFds`, `engine/pkg/system`, Cobra/config patterns) and the workspace is clean.

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`, but the captured signal does not identify a Moby source bug: CPU was only `0.1%`, process state was sleeping, strace excerpts are mostly `FUTEX_WAIT_PRIVATE`, and the hot symbol is kernel-side `bpf_lsm_file_permission`. The “socket-churn” label is profiler-derived and not backed by a source-level stack or reproduced user-visible failure.

## Evidence Confidence
inferred

## Proposed Subject
No source patch yet: diagnose idle `dockerd` profiler signal before changing Moby.

## Patch Plan
Do not edit files in this pass, and do not present this as a confirmed Docker bug. Before any upstream-style patch, collect extra evidence that ties the signal to Moby code: symbolized goroutine/profile data or a reproducible `fd://` listener churn case.

Relevant code path is `engine/cmd/dockerd/docker.go` -> `runDaemon`/`loadListeners` in `engine/cmd/dockerd/daemon.go` -> `listeners.Init`/`listenFD` in `engine/daemon/listeners/listeners_linux.go`. Local conventions/helpers to preserve if a later patch is justified: `log.G(ctx)` for logging, `github.com/pkg/errors` wrapping already used in this subsystem, `go-systemd/activation` for inherited sockets, and `go-connections/sockets` for listener creation. No relevant local locking or custom memory helpers were found in this path.

No prior Fixer patch was found to improve or replace; the tree is clean and only Debian quilt patches are applied. If later evidence proves a listener cleanup issue, use a small bounded loop/defer-based cleanup in `listenFD` or `loadListeners`; avoid awkward `goto` control flow.

## Risks
A source patch based only on this bundle would likely be speculative: the implicated package is the kernel, the backtraces are unsymbolized, and the observed process is mostly idle. Changing listener behavior around `fd://` could regress systemd socket activation, TLS activation listeners, or multi-listener configurations.

## Validation
Start from the workspace root with the package-level entrypoint: `dpkg-buildpackage -us -uc -b` or, if time-bound, `debian/rules build` followed by `debian/rules override_dh_auto_test`.

Focused checks after any justified listener patch: `cd engine && go test ./cmd/dockerd ./daemon/listeners ./opts`.

Bounded independent reproduction attempt before editing: run a socket-activation-style `dockerd -H fd:// --validate` or the existing `TestLoadListenerNoAddr`, then capture a short `strace -f -e futex,accept4,epoll_wait`/`perf top` sample to see whether the claimed socket churn appears. Do not claim `reproduced` unless that command shows the same failure signal.

## Patch Pass

Subject: Diagnose idle dockerd profiler signal

## Commit Message
No source change. The collected evidence points to an idle `dockerd` sample, not a confirmed Moby bug, so this is left as an upstream-ready diagnosis instead of a speculative patch.

## Evidence Confidence
inferred

## Issue Connection
The likely root cause from the perf, strace, and `/proc` evidence is that `dockerd` was sampled while mostly idle: the process state was `S (sleeping)`, CPU was only `0.1%`, `/proc/sched` showed mostly voluntary context switches, and strace was dominated by `FUTEX_WAIT_PRIVATE`. The perf hot symbol was kernel-side `bpf_lsm_file_permission`, and Fixer’s “socket-churn” classification means inferred repeated socket or IPC activity, not a symbolized Moby stack.

I inspected the `dockerd` entrypoint and the relevant listener path: `engine/cmd/dockerd/docker.go`, `loadListeners` in `engine/cmd/dockerd/daemon.go`, and `listenFD` in `engine/daemon/listeners/listeners_linux.go`. That path already uses local conventions and helpers: `log.G(ctx)` for logging, `github.com/pkg/errors` wrapping, `go-systemd/activation` for systemd socket activation, and `go-connections/sockets` for listener creation. I found no relevant local locking, memory, or process-spawning helper that would justify a change here.

No code change was made because the evidence remains indirect and unsymbolized, and I could not gather stronger local evidence. The expected effect is avoiding an upstream patch that would change `fd://` socket activation behavior without a demonstrated source-level defect.

## Git Add Paths
None

## Validation
`timeout 120s dpkg-buildpackage -us -uc -b` from the workspace root did not reach build or test. It failed immediately at `dpkg-checkbuilddeps` with unmet build dependencies, starting with `dh-golang (>= 1.14~)`, `golang-any`, `go-md2man`, and many Go library `-dev` packages.

Independent reproduction attempt: `go test -mod=vendor ./cmd/dockerd -run TestLoadListenerNoAddr -count=1 -v` in `engine`. This did not reproduce the reported signal; it was blocked by inconsistent vendoring between Debian’s patched `go.mod` and `vendor/modules.txt`.

I also retried in a temporary GOPATH with `GO111MODULE=off`, matching Debian’s rules. That was blocked because the Debian source workspace does not include all vendored dependency source directories and the sandbox lacks the corresponding system Go packages. The tree remains clean.

## Review Pass 1

RESULT: ok

No source diff was left, which is appropriate for the indirect profiler/strace evidence. The author response includes valid `## Evidence Confidence` as `inferred`, does not claim reproduction, names the relevant `dockerd` listener path and local helpers, attempts a workspace-root build first, and reports bounded reproduction attempts plus blockers.

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`, but the captured signal does not identify a Moby source bug: CPU was only `0.1%`, process state was sleeping, strace excerpts are mostly `FUTEX_WAIT_PRIVATE`, and the hot symbol is kernel-side `bpf_lsm_file_permission`. The “socket-churn” label is profiler-derived and not backed by a source-level stack or reproduced user-visible failure.

## Evidence Confidence
inferred

## Proposed Subject
No source patch yet: diagnose idle `dockerd` profiler signal before changing Moby.

## Patch Plan
Do not edit files in this pass, and do not present this as a confirmed Docker bug. Before any upstream-style patch, collect extra evidence that ties the signal to Moby code: symbolized goroutine/profile data or a reproducible `fd://` listener churn case.

Relevant code path is `engine/cmd/dockerd/docker.go` -> `runDaemon`/`loadListeners` in `engine/cmd/dockerd/daemon.go` -> `listeners.Init`/`listenFD` in `engine/daemon/listeners/listeners_linux.go`. Local conventions/helpers to preserve if a later patch is justified: `log.G(ctx)` for logging, `github.com/pkg/errors` wrapping already used in this subsystem, `go-systemd/activation` for inherited sockets, and `go-connections/sockets` for listener creation. No relevant local locking or custom memory helpers were found in this path.

No prior Fixer patch was found to improve or replace; the tree is clean and only Debian quilt patches are applied. If later evidence proves a listener cleanup issue, use a small bounded loop/defer-based cleanup in `listenFD` or `loadListeners`; avoid awkward `goto` control flow.

## Risks
A source patch based only on this bundle would likely be speculative: the implicated package is the kernel, the backtraces are unsymbolized, and the observed process is mostly idle. Changing listener behavior around `fd://` could regress systemd socket activation, TLS activation listeners, or multi-listener configurations.

## Validation
Start from the workspace root with the package-level entrypoint: `dpkg-buildpackage -us -uc -b` or, if time-bound, `debian/rules build` followed by `debian/rules override_dh_auto_test`.

Focused checks after any justified listener patch: `cd engine && go test ./cmd/dockerd ./daemon/listeners ./opts`.

Bounded independent reproduction attempt before editing: run a socket-activation-style `dockerd -H fd:// --validate` or the existing `TestLoadListenerNoAddr`, then capture a short `strace -f -e futex,accept4,epoll_wait`/`perf top` sample to see whether the claimed socket churn appears. Do not claim `reproduced` unless that command shows the same failure signal.

## Patch Pass

Subject: Diagnose idle dockerd profiler signal

## Commit Message
No source change. The collected evidence points to an idle `dockerd` sample, not a confirmed Moby bug, so this is left as an upstream-ready diagnosis instead of a speculative patch.

## Evidence Confidence
inferred

## Issue Connection
The likely root cause from the perf, strace, and `/proc` evidence is that `dockerd` was sampled while mostly idle: the process state was `S (sleeping)`, CPU was only `0.1%`, `/proc/sched` showed mostly voluntary context switches, and strace was dominated by `FUTEX_WAIT_PRIVATE`. The perf hot symbol was kernel-side `bpf_lsm_file_permission`, and Fixer’s “socket-churn” classification means inferred repeated socket or IPC activity, not a symbolized Moby stack.

I inspected the `dockerd` entrypoint and the relevant listener path: `engine/cmd/dockerd/docker.go`, `loadListeners` in `engine/cmd/dockerd/daemon.go`, and `listenFD` in `engine/daemon/listeners/listeners_linux.go`. That path already uses local conventions and helpers: `log.G(ctx)` for logging, `github.com/pkg/errors` wrapping, `go-systemd/activation` for systemd socket activation, and `go-connections/sockets` for listener creation. I found no relevant local locking, memory, or process-spawning helper that would justify a change here.

No code change was made because the evidence remains indirect and unsymbolized, and I could not gather stronger local evidence. The expected effect is avoiding an upstream patch that would change `fd://` socket activation behavior without a demonstrated source-level defect.

## Git Add Paths
None

## Validation
`timeout 120s dpkg-buildpackage -us -uc -b` from the workspace root did not reach build or test. It failed immediately at `dpkg-checkbuilddeps` with unmet build dependencies, starting with `dh-golang (>= 1.14~)`, `golang-any`, `go-md2man`, and many Go library `-dev` packages.

Independent reproduction attempt: `go test -mod=vendor ./cmd/dockerd -run TestLoadListenerNoAddr -count=1 -v` in `engine`. This did not reproduce the reported signal; it was blocked by inconsistent vendoring between Debian’s patched `go.mod` and `vendor/modules.txt`.

I also retried in a temporary GOPATH with `GO111MODULE=off`, matching Debian’s rules. That was blocked because the Debian source workspace does not include all vendored dependency source directories and the sandbox lacks the corresponding system Go packages. The tree remains clean.

## Review Pass 1

RESULT: ok

No source diff was left, which is appropriate for the indirect profiler/strace evidence. The author response includes valid `## Evidence Confidence` as `inferred`, does not claim reproduction, names the relevant `dockerd` listener path and local helpers, attempts a workspace-root build first, and reports bounded reproduction attempts plus blockers.

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, mostly sleeping in futex waits, very low CPU, and a profiler classifier of `socket-churn`. The embedded evidence has no symbolic Go stack, no reproduced user-visible failure, and the raw artifact paths are not available in this workspace. The `bpf_lsm_file_permission` hot path and futex-heavy strace excerpt are not enough to identify a specific Moby source bug.

## Evidence Confidence

inferred

## Proposed Subject

No source patch yet: collect a symbolized daemon trace before changing Moby’s listener or containerd client code.

## Patch Plan

1. Do not edit source in this pass. An inferred source patch would not be pull-request-ready because the evidence does not identify a faulty loop, leaked listener, or bad retry path.
2. Treat `dockerd` as the application entrypoint first. I inspected `engine/cmd/dockerd/docker.go`, `engine/cmd/dockerd/daemon.go`, `engine/daemon/listeners/listeners_linux.go`, and the containerd client setup in `engine/daemon/daemon.go`.
3. Local conventions/helpers found: Moby uses `containerd/log` for logging, `github.com/docker/go-connections/sockets` for TCP/Unix listener creation, `coreos/go-systemd/activation` for `fd://`, and `dialer.ContextDialer` plus gRPC `ConnectParams` for containerd connections. Any future patch should use those helpers rather than ad hoc socket or logging code.
4. No prior Fixer patch was found. Debian patches touch the systemd `dockerd` binary path and test/build issues, but nothing that should be improved or replaced for this evidence.
5. If extra evidence later points to a real retry/churn loop, keep the fix bounded in the responsible subsystem and avoid awkward control flow such as broad `goto` retry loops; prefer a small helper with `context`, `time.Timer`, or existing gRPC backoff settings.

## Risks

Changing listener activation or containerd dial behavior without a symbolic stack risks regressing normal daemon startup under systemd. The observed futex waits and `waitid(P_PIDFD, ...)` entries may be normal idle daemon/container supervision behavior rather than a bug.

## Validation

From the workspace root, the broad reproducible project test entrypoint to try before any focused check is `cd engine && make test-unit`, per `engine/TESTING.md` and `engine/hack/README.md`.

Bounded independent reproduction attempt: on a safe disposable host or already-running matching daemon, collect `timeout 10s strace -ff -e trace=socket,connect,accept4,futex,waitid -p <dockerd-pid>` plus `SIGQUIT`/Go goroutine stacks or a symbolized `gdb` backtrace. Do not claim reproduction unless that command shows an actual repeating socket/connect pattern tied to a Moby frame.

## Patch Pass

Subject: Diagnose dockerd profiler evidence without patch

## Commit Message
No source patch was produced. The available evidence is profiler and `/proc` data showing a sleeping `dockerd`, but it does not identify a Moby source-level retry loop, leaked listener, or failed API path. A patch would be speculative without a symbolized Go stack or a reproducible socket-churn trace.

## Evidence Confidence
inferred

## Issue Connection
The likely root cause from the collected perf, strace, and `/proc` evidence is not a confirmed Moby bug yet. Fixer observed `dockerd` with 185 threads, `S (sleeping)` state, 0.1% max CPU, many unfinished `futex(... FUTEX_WAIT_PRIVATE ...)` calls, a few `waitid(P_PIDFD, ...)` calls, and a profiler classifier of `socket-churn`; the perf hot path was in the kernel symbol `bpf_lsm_file_permission`, not in a symbolized Moby frame.

The cautious inference is that this may be normal idle Go runtime/container supervision activity, or a kernel/security-hook cost around file/socket permission checks, rather than an actionable daemon loop. The captured backtraces are stripped `??` frames and the raw investigation artifacts referenced by the bundle are not present, so I could not tie the signal to `dockerd` listener setup, containerd dialing, or API serving code.

I followed the saved plan and made no source change. In the inspected subsystem, Moby already uses local helpers and conventions: `containerd/log` for logging, `github.com/docker/go-connections/sockets` for Unix/TCP sockets, `coreos/go-systemd/activation` for `fd://` systemd socket activation, and `dialer.ContextDialer` plus gRPC `ConnectParams` for containerd connections. No relevant prior Fixer patch was found. The expected effect is no runtime behavior change; this is a no-patch diagnosis suitable for an upstream report requesting symbolized goroutine stacks or a bounded strace/perf comparison before code is changed.

## Git Add Paths
None

## Validation
`timeout 45s bash -lc 'cd engine && make test-unit'`  
Blocked before tests ran: the Makefile invoked `docker buildx build`, which failed with `ERROR: mkdir /root/.docker: read-only file system`.

`timeout 60s bash -lc 'cd engine && HOME=/tmp GOCACHE=/tmp/gocache go test ./cmd/dockerd ./daemon/listeners'`  
Blocked by module setup: many imports failed with `cannot find module providing package ...: import lookup disabled by -mod=readonly` and Go reported that the vendor directory was not used.

Bounded independent reproduction attempt:  
`bash -lc 'set -eu; pid=$(pgrep -n dockerd || true); if [ -z "$pid" ]; then echo "no dockerd process available for bounded strace reproduction"; exit 2; fi; echo "dockerd pid: $pid"; timeout 5s strace -ff -e trace=socket,connect,accept4,futex,waitid -p "$pid"'`  
Result: no `dockerd` process was available in this workspace, so the socket/futex signal was not independently reproduced.

## 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 claiming a confirmed Moby bug. The no-patch diagnosis is consistent with the evidence bundle: profiler/strace excerpts show a sleeping `dockerd` with futex waits and unsymbolized frames, but no source-level retry loop or reproducible failure.

The response also names the relevant Moby helper conventions (`containerd/log`, `go-connections/sockets`, systemd activation helpers, containerd/gRPC dial helpers), reports the project-level validation attempt and exact blocker, and does not invent a reproducer or user-visible crash.

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, mostly sleeping in futex waits, very low CPU, and a profiler classifier of `socket-churn`. The embedded evidence has no symbolic Go stack, no reproduced user-visible failure, and the raw artifact paths are not available in this workspace. The `bpf_lsm_file_permission` hot path and futex-heavy strace excerpt are not enough to identify a specific Moby source bug.

## Evidence Confidence

inferred

## Proposed Subject

No source patch yet: collect a symbolized daemon trace before changing Moby’s listener or containerd client code.

## Patch Plan

1. Do not edit source in this pass. An inferred source patch would not be pull-request-ready because the evidence does not identify a faulty loop, leaked listener, or bad retry path.
2. Treat `dockerd` as the application entrypoint first. I inspected `engine/cmd/dockerd/docker.go`, `engine/cmd/dockerd/daemon.go`, `engine/daemon/listeners/listeners_linux.go`, and the containerd client setup in `engine/daemon/daemon.go`.
3. Local conventions/helpers found: Moby uses `containerd/log` for logging, `github.com/docker/go-connections/sockets` for TCP/Unix listener creation, `coreos/go-systemd/activation` for `fd://`, and `dialer.ContextDialer` plus gRPC `ConnectParams` for containerd connections. Any future patch should use those helpers rather than ad hoc socket or logging code.
4. No prior Fixer patch was found. Debian patches touch the systemd `dockerd` binary path and test/build issues, but nothing that should be improved or replaced for this evidence.
5. If extra evidence later points to a real retry/churn loop, keep the fix bounded in the responsible subsystem and avoid awkward control flow such as broad `goto` retry loops; prefer a small helper with `context`, `time.Timer`, or existing gRPC backoff settings.

## Risks

Changing listener activation or containerd dial behavior without a symbolic stack risks regressing normal daemon startup under systemd. The observed futex waits and `waitid(P_PIDFD, ...)` entries may be normal idle daemon/container supervision behavior rather than a bug.

## Validation

From the workspace root, the broad reproducible project test entrypoint to try before any focused check is `cd engine && make test-unit`, per `engine/TESTING.md` and `engine/hack/README.md`.

Bounded independent reproduction attempt: on a safe disposable host or already-running matching daemon, collect `timeout 10s strace -ff -e trace=socket,connect,accept4,futex,waitid -p <dockerd-pid>` plus `SIGQUIT`/Go goroutine stacks or a symbolized `gdb` backtrace. Do not claim reproduction unless that command shows an actual repeating socket/connect pattern tied to a Moby frame.

## Patch Pass

Subject: Diagnose dockerd profiler evidence without patch

## Commit Message
No source patch was produced. The available evidence is profiler and `/proc` data showing a sleeping `dockerd`, but it does not identify a Moby source-level retry loop, leaked listener, or failed API path. A patch would be speculative without a symbolized Go stack or a reproducible socket-churn trace.

## Evidence Confidence
inferred

## Issue Connection
The likely root cause from the collected perf, strace, and `/proc` evidence is not a confirmed Moby bug yet. Fixer observed `dockerd` with 185 threads, `S (sleeping)` state, 0.1% max CPU, many unfinished `futex(... FUTEX_WAIT_PRIVATE ...)` calls, a few `waitid(P_PIDFD, ...)` calls, and a profiler classifier of `socket-churn`; the perf hot path was in the kernel symbol `bpf_lsm_file_permission`, not in a symbolized Moby frame.

The cautious inference is that this may be normal idle Go runtime/container supervision activity, or a kernel/security-hook cost around file/socket permission checks, rather than an actionable daemon loop. The captured backtraces are stripped `??` frames and the raw investigation artifacts referenced by the bundle are not present, so I could not tie the signal to `dockerd` listener setup, containerd dialing, or API serving code.

I followed the saved plan and made no source change. In the inspected subsystem, Moby already uses local helpers and conventions: `containerd/log` for logging, `github.com/docker/go-connections/sockets` for Unix/TCP sockets, `coreos/go-systemd/activation` for `fd://` systemd socket activation, and `dialer.ContextDialer` plus gRPC `ConnectParams` for containerd connections. No relevant prior Fixer patch was found. The expected effect is no runtime behavior change; this is a no-patch diagnosis suitable for an upstream report requesting symbolized goroutine stacks or a bounded strace/perf comparison before code is changed.

## Git Add Paths
None

## Validation
`timeout 45s bash -lc 'cd engine && make test-unit'`  
Blocked before tests ran: the Makefile invoked `docker buildx build`, which failed with `ERROR: mkdir /root/.docker: read-only file system`.

`timeout 60s bash -lc 'cd engine && HOME=/tmp GOCACHE=/tmp/gocache go test ./cmd/dockerd ./daemon/listeners'`  
Blocked by module setup: many imports failed with `cannot find module providing package ...: import lookup disabled by -mod=readonly` and Go reported that the vendor directory was not used.

Bounded independent reproduction attempt:  
`bash -lc 'set -eu; pid=$(pgrep -n dockerd || true); if [ -z "$pid" ]; then echo "no dockerd process available for bounded strace reproduction"; exit 2; fi; echo "dockerd pid: $pid"; timeout 5s strace -ff -e trace=socket,connect,accept4,futex,waitid -p "$pid"'`  
Result: no `dockerd` process was available in this workspace, so the socket/futex signal was not independently reproduced.

## 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 claiming a confirmed Moby bug. The no-patch diagnosis is consistent with the evidence bundle: profiler/strace excerpts show a sleeping `dockerd` with futex waits and unsymbolized frames, but no source-level retry loop or reproducible failure.

The response also names the relevant Moby helper conventions (`containerd/log`, `go-connections/sockets`, systemd activation helpers, containerd/gRPC dial helpers), reports the project-level validation attempt and exact blocker, and does not invent a reproducer or user-visible crash.

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 many sleeping threads in futex waits, low CPU, and an indirect `socket-churn` classification. The hottest sampled symbol was kernel-side `bpf_lsm_file_permission`, and the implicated package was the kernel, not a symbolized Moby frame. The raw strace path named in the evidence bundle is not present in this workspace, so there is not enough source-level evidence to justify an upstream Moby patch yet.

## Evidence Confidence
inferred

## Proposed Subject
No source patch yet: collect symbolized dockerd/containerd evidence before proposing a Moby change.

## Patch Plan
Do not edit files in this pass. I inspected the dockerd entrypoint first (`engine/cmd/dockerd`) and then the containerd-facing runtime path (`engine/daemon/daemon.go`, `engine/libcontainerd/remote/client.go`). A plausible area is the libcontainerd event stream reconnect path, but the current evidence does not prove it is responsible for the observed futex/socket profile.

Before any patch, collect the missing full raw artifacts or equivalent fresh data: symbolized goroutine dump/backtrace, full `strace -f` with socket/connect/futex/waitid counts, fd targets, and containerd availability/logs. If that evidence points to `processEventStream` or `waitServe`, design a small upstream-style change using existing conventions: `context` cancellation, `containerd/log` via `log.G(ctx)`, existing gRPC/containerd dial options, and a bounded retry/backoff loop. Avoid awkward control flow such as an avoidable `goto`; prefer a clear loop with explicit exit on context cancellation.

No prior Fixer patch for `90267`, futex/socket churn, or `bpf_lsm_file_permission` was found in the workspace or Debian patch stack.

## Risks
A source patch from the current bundle would be speculative: the process was sleeping, CPU was only 0.1%, the hot path is kernel-side, and the evidence lacks symbolized Go frames or a concrete user-visible failure.

Changing dockerd/containerd reconnect behavior without confirmed causality could regress daemon recovery after containerd restarts.

## Validation
Start with the reproducible project entrypoints from the workspace root: `dpkg-buildpackage -us -uc -b` for the Debian package path, or at minimum `cd engine && make test-unit` per upstream Moby testing docs before any focused package test.

For a bounded independent reproduction attempt, build/run a local dockerd under `timeout` with a controlled temporary data root and containerd socket condition, capturing `strace -f -e trace=futex,connect,accept,waitid`. Only claim reproduction if it shows the same repeated futex/socket signal; otherwise report it as not independently reproduced.

## Patch Pass

Subject: diagnose dockerd futex profile without source change

## Commit Message
No source change. The collected profile points to a sleeping dockerd process with many Go runtime futex waits, but it does not identify a Moby code path that is safe to change upstream.

## Evidence Confidence
inferred

## Issue Connection
The collected signal is a 3-second perf profile and 5-second strace summary for `/usr/sbin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock`: dockerd had 185 threads, process state `S (sleeping)`, about 0.1% CPU, repeated `FUTEX_WAIT_PRIVATE` entries, a few `waitid(P_PIDFD, ...)` entries, and a kernel hot symbol `bpf_lsm_file_permission`. The likely root cause from the `/proc`, perf, and strace evidence is not a confirmed busy loop in Moby; it is a mostly parked Go daemon whose threads are blocked in futex waits, with the profiler attributing sampled kernel time to an LSM/BPF permission hook.

I followed the saved plan and did not land a source patch. I inspected the dockerd entrypoint first, then the containerd-facing daemon code. The closest plausible area is `engine/libcontainerd/remote/client.go`, where the libcontainerd event stream subscribes to containerd task events and waits for containerd readiness before resubscribing. That code already uses the local conventions I would use for a real patch: `context` cancellation, `containerd/log` via `log.G(ctx)`, and containerd/gRPC dial helpers such as `dialer.ContextDialer`. The evidence does not connect the observed futex waits or kernel `bpf_lsm_file_permission` samples to that path, so changing it would be speculative.

The expected effect of this no-patch result is to avoid an upstream-unready change and preserve a useful upstream bug-report diagnosis: the next evidence needed is a symbolized goroutine dump or backtrace, complete strace/fd targets, and containerd logs around the same sample window.

## Git Add Paths
None

## Validation
`timeout 120s dpkg-buildpackage -us -uc -b` from the workspace root failed before build because `dpkg-checkbuilddeps` reported unmet build dependencies, starting with `dh-golang`, `golang-any`, `go-md2man`, and many Go library `-dev` packages.

`cd engine && go test ./libcontainerd/remote` also failed: Go could not resolve required modules with import lookup disabled by `-mod=readonly`, and the environment also lacked `GOCACHE`/`HOME`.

Bounded independent reproduction attempt: `timeout 10s strace -f -e trace=futex,connect,accept,accept4,waitid /usr/sbin/dockerd --validate` did not run because ptrace is blocked in this sandbox: `PTRACE_TRACEME: Operation not permitted` and `ptrace(PTRACE_SEIZE, 7): Operation not permitted`.

`git diff --stat` is empty; no source files were changed.

## Review Pass 1

RESULT: ok

No source diff is present against the workspace or original snapshot, which is appropriate for the `inferred` evidence level. The author response includes the required sections, does not overclaim reproduction, attempts the workspace-root build entrypoint, reports exact blockers, and gives a bounded reproduction attempt that was blocked by ptrace permissions.

The diagnosis is consistent with the evidence: low-CPU sleeping dockerd, futex waits, and kernel-side `bpf_lsm_file_permission` samples do not justify an upstream Moby source patch without stronger symbolized evidence.

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 many sleeping threads in futex waits, low CPU, and an indirect `socket-churn` classification. The hottest sampled symbol was kernel-side `bpf_lsm_file_permission`, and the implicated package was the kernel, not a symbolized Moby frame. The raw strace path named in the evidence bundle is not present in this workspace, so there is not enough source-level evidence to justify an upstream Moby patch yet.

## Evidence Confidence
inferred

## Proposed Subject
No source patch yet: collect symbolized dockerd/containerd evidence before proposing a Moby change.

## Patch Plan
Do not edit files in this pass. I inspected the dockerd entrypoint first (`engine/cmd/dockerd`) and then the containerd-facing runtime path (`engine/daemon/daemon.go`, `engine/libcontainerd/remote/client.go`). A plausible area is the libcontainerd event stream reconnect path, but the current evidence does not prove it is responsible for the observed futex/socket profile.

Before any patch, collect the missing full raw artifacts or equivalent fresh data: symbolized goroutine dump/backtrace, full `strace -f` with socket/connect/futex/waitid counts, fd targets, and containerd availability/logs. If that evidence points to `processEventStream` or `waitServe`, design a small upstream-style change using existing conventions: `context` cancellation, `containerd/log` via `log.G(ctx)`, existing gRPC/containerd dial options, and a bounded retry/backoff loop. Avoid awkward control flow such as an avoidable `goto`; prefer a clear loop with explicit exit on context cancellation.

No prior Fixer patch for `90267`, futex/socket churn, or `bpf_lsm_file_permission` was found in the workspace or Debian patch stack.

## Risks
A source patch from the current bundle would be speculative: the process was sleeping, CPU was only 0.1%, the hot path is kernel-side, and the evidence lacks symbolized Go frames or a concrete user-visible failure.

Changing dockerd/containerd reconnect behavior without confirmed causality could regress daemon recovery after containerd restarts.

## Validation
Start with the reproducible project entrypoints from the workspace root: `dpkg-buildpackage -us -uc -b` for the Debian package path, or at minimum `cd engine && make test-unit` per upstream Moby testing docs before any focused package test.

For a bounded independent reproduction attempt, build/run a local dockerd under `timeout` with a controlled temporary data root and containerd socket condition, capturing `strace -f -e trace=futex,connect,accept,waitid`. Only claim reproduction if it shows the same repeated futex/socket signal; otherwise report it as not independently reproduced.

## Patch Pass

Subject: diagnose dockerd futex profile without source change

## Commit Message
No source change. The collected profile points to a sleeping dockerd process with many Go runtime futex waits, but it does not identify a Moby code path that is safe to change upstream.

## Evidence Confidence
inferred

## Issue Connection
The collected signal is a 3-second perf profile and 5-second strace summary for `/usr/sbin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock`: dockerd had 185 threads, process state `S (sleeping)`, about 0.1% CPU, repeated `FUTEX_WAIT_PRIVATE` entries, a few `waitid(P_PIDFD, ...)` entries, and a kernel hot symbol `bpf_lsm_file_permission`. The likely root cause from the `/proc`, perf, and strace evidence is not a confirmed busy loop in Moby; it is a mostly parked Go daemon whose threads are blocked in futex waits, with the profiler attributing sampled kernel time to an LSM/BPF permission hook.

I followed the saved plan and did not land a source patch. I inspected the dockerd entrypoint first, then the containerd-facing daemon code. The closest plausible area is `engine/libcontainerd/remote/client.go`, where the libcontainerd event stream subscribes to containerd task events and waits for containerd readiness before resubscribing. That code already uses the local conventions I would use for a real patch: `context` cancellation, `containerd/log` via `log.G(ctx)`, and containerd/gRPC dial helpers such as `dialer.ContextDialer`. The evidence does not connect the observed futex waits or kernel `bpf_lsm_file_permission` samples to that path, so changing it would be speculative.

The expected effect of this no-patch result is to avoid an upstream-unready change and preserve a useful upstream bug-report diagnosis: the next evidence needed is a symbolized goroutine dump or backtrace, complete strace/fd targets, and containerd logs around the same sample window.

## Git Add Paths
None

## Validation
`timeout 120s dpkg-buildpackage -us -uc -b` from the workspace root failed before build because `dpkg-checkbuilddeps` reported unmet build dependencies, starting with `dh-golang`, `golang-any`, `go-md2man`, and many Go library `-dev` packages.

`cd engine && go test ./libcontainerd/remote` also failed: Go could not resolve required modules with import lookup disabled by `-mod=readonly`, and the environment also lacked `GOCACHE`/`HOME`.

Bounded independent reproduction attempt: `timeout 10s strace -f -e trace=futex,connect,accept,accept4,waitid /usr/sbin/dockerd --validate` did not run because ptrace is blocked in this sandbox: `PTRACE_TRACEME: Operation not permitted` and `ptrace(PTRACE_SEIZE, 7): Operation not permitted`.

`git diff --stat` is empty; no source files were changed.

## Review Pass 1

RESULT: ok

No source diff is present against the workspace or original snapshot, which is appropriate for the `inferred` evidence level. The author response includes the required sections, does not overclaim reproduction, attempts the workspace-root build entrypoint, reports exact blockers, and gives a bounded reproduction attempt that was blocked by ptrace permissions.

The diagnosis is consistent with the evidence: low-CPU sleeping dockerd, futex waits, and kernel-side `bpf_lsm_file_permission` samples do not justify an upstream Moby source patch without stronger symbolized evidence.

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 low CPU, sleeping in futex waits, a few `waitid(P_PIDFD, ...)` waits, and an automatic `socket-churn` label. The evidence is indirect and unsymbolized, and the sampled command line uses `--containerd=/run/containerd/containerd.sock`, so the managed-containerd supervisor path is likely not active for this process.

## Evidence Confidence

inferred

## Proposed Subject

No source patch yet: diagnose `dockerd` wait/socket profile before editing.

## Patch Plan

Do not edit in this pass. The current evidence does not identify a Moby source-level defect clearly enough for an upstream-ready patch.

Follow-up investigation should first symbolicate `dockerd` frames or collect Go goroutine/pprof data for the sampled process. If it implicates Docker-owned containerd client setup, use existing conventions in `engine/daemon/daemon.go`: `dialer.ContextDialer`, `grpcerrors` interceptors, `log.G`, bounded `context.WithTimeout`, and existing `grpc.ConnectParams`. If it implicates managed containerd shutdown/startup, follow `engine/libcontainerd/supervisor` helpers such as `process.Alive` and `process.Kill`.

Avoid adding broad control flow or `goto`; any later fix should be a small bounded retry/backoff, cancellation, or cleanup change in the implicated path. No prior Fixer source patch was found to improve or replace, only the packaging baseline/quilt state.

## Risks

A speculative patch could change daemon/containerd lifecycle behavior without proving it addresses the observed profile.

The evidence may be normal idle Go runtime behavior: process state is sleeping, CPU is only 0.1%, and the visible syscalls are mostly blocking futex waits.

The kernel hot symbol `bpf_lsm_file_permission` and missing raw artifacts make it possible this is kernel/LSM or environment noise rather than a `docker.io` source issue.

## Validation

Primary reproducible entrypoint from the workspace root after any future code change: `cd engine && make test-unit TESTDIRS=./cmd/dockerd,./daemon,./libcontainerd/...`.

Focused checks if a small Go patch is later made: `cd engine && go test ./cmd/dockerd ./daemon ./libcontainerd/...` plus `gofmt -s -w` on edited files.

Bounded independent reproduction attempt before editing: start `dockerd` with an external `--containerd=/run/containerd/containerd.sock`, then capture a short `strace -f -p <dockerd-pid>` or goroutine dump to see whether the same futex/waitid pattern appears and whether it maps to Docker-owned code. Do not claim reproduction unless that command shows the same failure signal.

## Patch Pass

Subject: no patch: dockerd profile lacks a source-level cause

## Commit Message
The likely explanation from the collected perf, strace, and `/proc` evidence is an idle or blocked Go daemon, not a confirmed Docker source bug. `dockerd` was sleeping, using about 0.1% CPU, mostly blocked in futex waits, with unsymbolized frames and a kernel `bpf_lsm_file_permission` hotspot. No source change is included because the evidence does not identify a safe upstream patch.

## Evidence Confidence
inferred

## Issue Connection
The collected signal is a `dockerd` process started as `/usr/sbin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock`, in sleeping state, with strace dominated by `FUTEX_WAIT_PRIVATE` and a few `waitid(P_PIDFD, ...)` calls. The profiler labeled this as possible socket churn, but the process had very low CPU and the backtrace frames are unsymbolized.

The cautious code-level inference is that this does not yet point to a Docker-owned loop. The command line uses an external containerd socket, so the managed-containerd supervisor path in `engine/libcontainerd/supervisor` is likely not active for this process. The external-containerd client path already uses local Moby/containerd conventions: `dialer.ContextDialer`, `grpcerrors` interceptors, `log.G`, bounded `context.WithTimeout`, and gRPC connect parameters. The supervisor path also already uses local process helpers such as `process.Alive` and `process.Kill`.

The specific change made is none. This follows the saved plan in `plan-output.txt`: do not leave an inferred source diff without stronger symbolized or reproduced evidence. The expected effect is no runtime behavior change; the upstreamable next step is an issue/report with symbolized Go goroutine or pprof data from an affected daemon.

I reviewed `engine/CONTRIBUTING.md`, `engine/TESTING.md`, the `dockerd` containerd entrypoint code, and the local helper APIs before deciding not to patch.

## Git Add Paths
None

## Validation
Attempted documented workspace-root entrypoint:

`timeout 60s make -C engine test-unit TESTDIRS='./cmd/dockerd,./daemon,./libcontainerd/...'`

Blocked before tests: Docker build setup failed with `ERROR: mkdir /root/.docker: read-only file system`.

Focused fallback:

`go test ./cmd/dockerd ./daemon ./libcontainerd/...`

Blocked by module/cache setup: dependency import lookup disabled by `-mod=readonly`, vendor not used, and `GOCACHE`/`HOME` unavailable.

Second focused fallback:

`GOCACHE=/tmp/fixer-gocache GOFLAGS=-mod=vendor go test ./libcontainerd/supervisor`

Blocked by inconsistent Debian vendoring between `vendor/modules.txt` and `go.mod`.

Independent reproduction attempt:

`ls -ld /var/lib/fixer/investigations/2026-05-06T13-03-31.688538450+00-00-dockerd-b732bcc6a3ff; pgrep -a dockerd`

Blocked: the raw investigation directory is not present in this sandbox, and there is no local `dockerd` process to attach with strace or inspect for the same futex/waitid signal.

## Review Pass 1

RESULT: ok

No source changes are present, and the author correctly kept the response as an `inferred` no-patch diagnosis rather than presenting profiler-only, unsymbolized futex/strace evidence as a confirmed Docker bug.

The response includes the required sections, names the evidence limit, connects the sampled `--containerd=/run/containerd/containerd.sock` command line to why the managed supervisor path is unlikely, identifies relevant local helpers/conventions, and reports project-level validation plus exact blockers.

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 low CPU, sleeping in futex waits, a few `waitid(P_PIDFD, ...)` waits, and an automatic `socket-churn` label. The evidence is indirect and unsymbolized, and the sampled command line uses `--containerd=/run/containerd/containerd.sock`, so the managed-containerd supervisor path is likely not active for this process.

## Evidence Confidence

inferred

## Proposed Subject

No source patch yet: diagnose `dockerd` wait/socket profile before editing.

## Patch Plan

Do not edit in this pass. The current evidence does not identify a Moby source-level defect clearly enough for an upstream-ready patch.

Follow-up investigation should first symbolicate `dockerd` frames or collect Go goroutine/pprof data for the sampled process. If it implicates Docker-owned containerd client setup, use existing conventions in `engine/daemon/daemon.go`: `dialer.ContextDialer`, `grpcerrors` interceptors, `log.G`, bounded `context.WithTimeout`, and existing `grpc.ConnectParams`. If it implicates managed containerd shutdown/startup, follow `engine/libcontainerd/supervisor` helpers such as `process.Alive` and `process.Kill`.

Avoid adding broad control flow or `goto`; any later fix should be a small bounded retry/backoff, cancellation, or cleanup change in the implicated path. No prior Fixer source patch was found to improve or replace, only the packaging baseline/quilt state.

## Risks

A speculative patch could change daemon/containerd lifecycle behavior without proving it addresses the observed profile.

The evidence may be normal idle Go runtime behavior: process state is sleeping, CPU is only 0.1%, and the visible syscalls are mostly blocking futex waits.

The kernel hot symbol `bpf_lsm_file_permission` and missing raw artifacts make it possible this is kernel/LSM or environment noise rather than a `docker.io` source issue.

## Validation

Primary reproducible entrypoint from the workspace root after any future code change: `cd engine && make test-unit TESTDIRS=./cmd/dockerd,./daemon,./libcontainerd/...`.

Focused checks if a small Go patch is later made: `cd engine && go test ./cmd/dockerd ./daemon ./libcontainerd/...` plus `gofmt -s -w` on edited files.

Bounded independent reproduction attempt before editing: start `dockerd` with an external `--containerd=/run/containerd/containerd.sock`, then capture a short `strace -f -p <dockerd-pid>` or goroutine dump to see whether the same futex/waitid pattern appears and whether it maps to Docker-owned code. Do not claim reproduction unless that command shows the same failure signal.

## Patch Pass

Subject: no patch: dockerd profile lacks a source-level cause

## Commit Message
The likely explanation from the collected perf, strace, and `/proc` evidence is an idle or blocked Go daemon, not a confirmed Docker source bug. `dockerd` was sleeping, using about 0.1% CPU, mostly blocked in futex waits, with unsymbolized frames and a kernel `bpf_lsm_file_permission` hotspot. No source change is included because the evidence does not identify a safe upstream patch.

## Evidence Confidence
inferred

## Issue Connection
The collected signal is a `dockerd` process started as `/usr/sbin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock`, in sleeping state, with strace dominated by `FUTEX_WAIT_PRIVATE` and a few `waitid(P_PIDFD, ...)` calls. The profiler labeled this as possible socket churn, but the process had very low CPU and the backtrace frames are unsymbolized.

The cautious code-level inference is that this does not yet point to a Docker-owned loop. The command line uses an external containerd socket, so the managed-containerd supervisor path in `engine/libcontainerd/supervisor` is likely not active for this process. The external-containerd client path already uses local Moby/containerd conventions: `dialer.ContextDialer`, `grpcerrors` interceptors, `log.G`, bounded `context.WithTimeout`, and gRPC connect parameters. The supervisor path also already uses local process helpers such as `process.Alive` and `process.Kill`.

The specific change made is none. This follows the saved plan in `plan-output.txt`: do not leave an inferred source diff without stronger symbolized or reproduced evidence. The expected effect is no runtime behavior change; the upstreamable next step is an issue/report with symbolized Go goroutine or pprof data from an affected daemon.

I reviewed `engine/CONTRIBUTING.md`, `engine/TESTING.md`, the `dockerd` containerd entrypoint code, and the local helper APIs before deciding not to patch.

## Git Add Paths
None

## Validation
Attempted documented workspace-root entrypoint:

`timeout 60s make -C engine test-unit TESTDIRS='./cmd/dockerd,./daemon,./libcontainerd/...'`

Blocked before tests: Docker build setup failed with `ERROR: mkdir /root/.docker: read-only file system`.

Focused fallback:

`go test ./cmd/dockerd ./daemon ./libcontainerd/...`

Blocked by module/cache setup: dependency import lookup disabled by `-mod=readonly`, vendor not used, and `GOCACHE`/`HOME` unavailable.

Second focused fallback:

`GOCACHE=/tmp/fixer-gocache GOFLAGS=-mod=vendor go test ./libcontainerd/supervisor`

Blocked by inconsistent Debian vendoring between `vendor/modules.txt` and `go.mod`.

Independent reproduction attempt:

`ls -ld /var/lib/fixer/investigations/2026-05-06T13-03-31.688538450+00-00-dockerd-b732bcc6a3ff; pgrep -a dockerd`

Blocked: the raw investigation directory is not present in this sandbox, and there is no local `dockerd` process to attach with strace or inspect for the same futex/waitid signal.

## Review Pass 1

RESULT: ok

No source changes are present, and the author correctly kept the response as an `inferred` no-patch diagnosis rather than presenting profiler-only, unsymbolized futex/strace evidence as a confirmed Docker bug.

The response includes the required sections, names the evidence limit, connects the sampled `--containerd=/run/containerd/containerd.sock` command line to why the managed supervisor path is unlikely, identifies relevant local helpers/conventions, and reports project-level validation plus exact blockers.

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` mostly sleeping with many Go threads blocked in `futex`/`waitid`, very low CPU usage, and an indirect profiler label of `socket-churn` plus kernel `bpf_lsm_file_permission`. The bundled evidence does not identify a Moby source-level busy loop or a user-visible failure.

## Evidence Confidence

inferred

## Proposed Subject

No source patch yet: report/diagnose the profiler signal and collect stronger evidence before editing Moby. This should not be treated as a confirmed `dockerd` bug fix.

## Patch Plan

- Do not edit in this pass. The workspace is clean, so there is no prior Fixer patch to improve or replace.
- Start investigation from `engine/cmd/dockerd/docker.go` and `engine/cmd/dockerd/daemon.go`, then the containerd supervision/event paths only if new evidence points there.
- Follow Moby conventions from `engine/CONTRIBUTING.md` and `engine/TESTING.md`: Go changes need focused unit tests, `gofmt -s`, and no new `integration-cli` tests.
- Relevant local helpers/conventions found: `log.G(ctx)` for logging, `pkg/pidfile`, `pkg/process.Kill/Alive`, context-based cancellation, and containerd/grpc dialer helpers in `libcontainerd/supervisor`.
- Reject speculative control-flow patches, including avoidable `goto` or retry-loop rewrites, unless a concrete loop is proven.

## Risks

The evidence may describe normal idle daemon state or kernel/LSM overhead rather than a Moby defect. A source patch based only on the current bundle would risk changing daemon/containerd supervision behavior without a reproducible issue.

## Validation

Before any future focused check, use the repo entrypoint from the workspace root: `cd engine && make test-unit`.

Bounded independent reproduction attempt: run a local `dockerd` validation/smoke command under a short `strace`/`perf` window, if safe in the environment, and verify whether the same socket/futex signal appears with measurable CPU or request churn. Do not claim `reproduced` unless that command actually shows the failure.

## Patch Pass

Subject: diagnose dockerd profiler signal without patch

## Commit Message

No source change. The collected `dockerd` signal is profiler-only and points to an idle Go daemon under kernel security-hook overhead, not to a confirmed Moby retry loop or source-level bug. Leaving a source diff would be speculative and not pull-request-ready.

## Evidence Confidence

inferred

## Issue Connection

The collected signal is: `/usr/sbin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock` was sleeping with 185 threads, about 0.1% CPU, many `futex` waits, a few `waitid(P_PIDFD, ...)` waits, and a perf hot path in the kernel symbol `bpf_lsm_file_permission`. `futex` is the Linux primitive Go uses for parking threads; `waitid(P_PIDFD, ...)` waits for child process state through pidfds.

The cautious root-cause inference is that this was not a tight Moby loop. The `/proc` state and scheduler excerpt show an idle process, strace shows blocked waits rather than rapid completed syscalls, and the hot symbol is a kernel BPF LSM permission hook rather than a symbolized Docker daemon frame. I inspected the daemon entrypoint and nearby containerd supervision/event-stream code; the relevant loops use timers, context cancellation, `log.G(ctx)`, `pkg/pidfile`, `pkg/process`, and containerd gRPC dialer/interceptor helpers. I did not find a bounded, upstreamable code change that follows from the evidence.

I followed the saved plan and intentionally made no source change. The expected effect is to avoid sending maintainers a speculative patch for an indirect profiler signal; the useful upstream artifact would be a bug report with stronger runtime evidence, such as symbolized goroutine dumps, full strace/perf data, and a reproducible workload showing real churn.

## Git Add Paths

None

## Validation

`cd engine && timeout 120s make test-unit` failed before tests ran. Exact blocker: the target tried to build/load the Docker dev image and failed with `ERROR: mkdir /root/.docker: read-only file system`; it also printed `Failed to create stream fd: Operation not permitted`.

Independent reproduction attempt: `timeout 10s strace -f -e trace=futex,waitid,socket,connect -c /usr/sbin/dockerd --validate` was blocked by sandbox ptrace restrictions: `PTRACE_TRACEME: Operation not permitted` and `ptrace(PTRACE_SEIZE, 6): Operation not permitted`.

Narrow smoke check: `timeout 30s /usr/sbin/dockerd --validate` passed with `configuration OK`, but this does not reproduce the collected runtime signal.

Focused leaf check: `cd engine && timeout 120s go test ./libcontainerd/supervisor ./libcontainerd/remote ./cmd/dockerd` failed during setup because module lookup was disabled by `-mod=readonly` and dependencies were unavailable, for example `cannot find module providing package github.com/containerd/containerd/v2/client`; it also reported `GOCACHE is not defined and neither $XDG_CACHE_HOME nor $HOME are defined`.

## Review Pass 1

RESULT: ok

No source diff is present, and the author’s no-patch diagnosis is consistent with the evidence bundle. The response keeps `## Evidence Confidence` at `inferred`, does not invent a reproducer or user-visible failure, names the project-level test entrypoint attempted, reports exact blockers, and explains why a source patch would be speculative.

The maintainer-facing explanation is acceptable for a no-patch report: it connects the perf/strace/`/proc` signal to an idle `dockerd` diagnosis, names relevant local conventions/helpers (`log.G(ctx)`, `pkg/pidfile`, `pkg/process`, context cancellation, containerd gRPC helpers), and avoids overstating the evidence.

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` mostly sleeping with many Go threads blocked in `futex`/`waitid`, very low CPU usage, and an indirect profiler label of `socket-churn` plus kernel `bpf_lsm_file_permission`. The bundled evidence does not identify a Moby source-level busy loop or a user-visible failure.

## Evidence Confidence

inferred

## Proposed Subject

No source patch yet: report/diagnose the profiler signal and collect stronger evidence before editing Moby. This should not be treated as a confirmed `dockerd` bug fix.

## Patch Plan

- Do not edit in this pass. The workspace is clean, so there is no prior Fixer patch to improve or replace.
- Start investigation from `engine/cmd/dockerd/docker.go` and `engine/cmd/dockerd/daemon.go`, then the containerd supervision/event paths only if new evidence points there.
- Follow Moby conventions from `engine/CONTRIBUTING.md` and `engine/TESTING.md`: Go changes need focused unit tests, `gofmt -s`, and no new `integration-cli` tests.
- Relevant local helpers/conventions found: `log.G(ctx)` for logging, `pkg/pidfile`, `pkg/process.Kill/Alive`, context-based cancellation, and containerd/grpc dialer helpers in `libcontainerd/supervisor`.
- Reject speculative control-flow patches, including avoidable `goto` or retry-loop rewrites, unless a concrete loop is proven.

## Risks

The evidence may describe normal idle daemon state or kernel/LSM overhead rather than a Moby defect. A source patch based only on the current bundle would risk changing daemon/containerd supervision behavior without a reproducible issue.

## Validation

Before any future focused check, use the repo entrypoint from the workspace root: `cd engine && make test-unit`.

Bounded independent reproduction attempt: run a local `dockerd` validation/smoke command under a short `strace`/`perf` window, if safe in the environment, and verify whether the same socket/futex signal appears with measurable CPU or request churn. Do not claim `reproduced` unless that command actually shows the failure.

## Patch Pass

Subject: diagnose dockerd profiler signal without patch

## Commit Message

No source change. The collected `dockerd` signal is profiler-only and points to an idle Go daemon under kernel security-hook overhead, not to a confirmed Moby retry loop or source-level bug. Leaving a source diff would be speculative and not pull-request-ready.

## Evidence Confidence

inferred

## Issue Connection

The collected signal is: `/usr/sbin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock` was sleeping with 185 threads, about 0.1% CPU, many `futex` waits, a few `waitid(P_PIDFD, ...)` waits, and a perf hot path in the kernel symbol `bpf_lsm_file_permission`. `futex` is the Linux primitive Go uses for parking threads; `waitid(P_PIDFD, ...)` waits for child process state through pidfds.

The cautious root-cause inference is that this was not a tight Moby loop. The `/proc` state and scheduler excerpt show an idle process, strace shows blocked waits rather than rapid completed syscalls, and the hot symbol is a kernel BPF LSM permission hook rather than a symbolized Docker daemon frame. I inspected the daemon entrypoint and nearby containerd supervision/event-stream code; the relevant loops use timers, context cancellation, `log.G(ctx)`, `pkg/pidfile`, `pkg/process`, and containerd gRPC dialer/interceptor helpers. I did not find a bounded, upstreamable code change that follows from the evidence.

I followed the saved plan and intentionally made no source change. The expected effect is to avoid sending maintainers a speculative patch for an indirect profiler signal; the useful upstream artifact would be a bug report with stronger runtime evidence, such as symbolized goroutine dumps, full strace/perf data, and a reproducible workload showing real churn.

## Git Add Paths

None

## Validation

`cd engine && timeout 120s make test-unit` failed before tests ran. Exact blocker: the target tried to build/load the Docker dev image and failed with `ERROR: mkdir /root/.docker: read-only file system`; it also printed `Failed to create stream fd: Operation not permitted`.

Independent reproduction attempt: `timeout 10s strace -f -e trace=futex,waitid,socket,connect -c /usr/sbin/dockerd --validate` was blocked by sandbox ptrace restrictions: `PTRACE_TRACEME: Operation not permitted` and `ptrace(PTRACE_SEIZE, 6): Operation not permitted`.

Narrow smoke check: `timeout 30s /usr/sbin/dockerd --validate` passed with `configuration OK`, but this does not reproduce the collected runtime signal.

Focused leaf check: `cd engine && timeout 120s go test ./libcontainerd/supervisor ./libcontainerd/remote ./cmd/dockerd` failed during setup because module lookup was disabled by `-mod=readonly` and dependencies were unavailable, for example `cannot find module providing package github.com/containerd/containerd/v2/client`; it also reported `GOCACHE is not defined and neither $XDG_CACHE_HOME nor $HOME are defined`.

## Review Pass 1

RESULT: ok

No source diff is present, and the author’s no-patch diagnosis is consistent with the evidence bundle. The response keeps `## Evidence Confidence` at `inferred`, does not invent a reproducer or user-visible failure, names the project-level test entrypoint attempted, reports exact blockers, and explains why a source patch would be speculative.

The maintainer-facing explanation is acceptable for a no-patch report: it connects the perf/strace/`/proc` signal to an idle `dockerd` diagnosis, names relevant local conventions/helpers (`log.G(ctx)`, `pkg/pidfile`, `pkg/process`, context cancellation, containerd gRPC helpers), and avoids overstating the evidence.