rsync likely remains stuck in a busy-poll loop. A diagnosis report and patch proposal were created locally.
Published session
Prompt
## Plan Pass
You are planning a fixer patch before any edits happen.
Read the evidence bundle at `./evidence.json`. The prepared workspace is `./workspace` and it was acquired via `debian-source`. The original pre-edit snapshot is available at `./source` if you need to inspect it. For interpreter processes, plan from the script/application entrypoint evidence first and include the runtime only as a second investigation target unless the evidence proves a runtime bug.
Validation expectation: try the project-level build/test entrypoint from the workspace root before reporting only a focused leaf compile. Detected candidate(s): `./configure && make`. If the project-level command fails because dependencies or generated files are missing, include the exact command and failure reason in `## Validation`, then run the narrowest relevant compile/test that is still reproducible from a clean checkout.
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 `rsync` 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`
Validation expectation: try the project-level build/test entrypoint from the workspace root before reporting only a focused leaf compile. Detected candidate(s): `./configure && make`. If the project-level command fails because dependencies or generated files are missing, include the exact command and failure reason in `## Validation`, then run the narrowest relevant compile/test that is still reproducible from a clean checkout.
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 `rsync` 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. 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 `rsync` upstream patch, not just a Debian-local workaround.
Validation expectation: try the project-level build/test entrypoint from the workspace root before reporting only a focused leaf compile. Detected candidate(s): `./configure && make`, `make` and, if available, `make check`. If the project-level command fails because dependencies or generated files are missing, include the exact command and failure reason in `## Validation`, then run the narrowest relevant compile/test that is still reproducible from a clean checkout. 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 flagged `rsync --server ... --timeout=300 ...` as a likely busy-poll runaway, but the captured process was sleeping in `poll_schedule_timeout`, used ~`0.2%` CPU, and the visible `pselect6` call blocked for ~2.49s before an 8-byte read. That is more consistent with rsync’s normal `select()`-based I/O wait/timeout path than a proven spin.
## Evidence Confidence
inferred
## Proposed Subject
No source patch: diagnose rsync busy-poll finding as blocking I/O wait evidence.
## Patch Plan
Do not edit source from the current evidence. Before a source patch, collect stronger evidence: a longer `strace -ttT` showing repeated near-zero-duration `pselect6/select` returns, or a symbolized stack from an unstripped rsync build mapping the sampled frames into a concrete loop.
Local conventions found: `README.md` is the relevant top-level project guide found; nearby I/O code uses `io.c` helpers such as `perform_io()`, `safe_read()`, `set_io_timeout()`, `check_timeout()`, `maybe_send_keepalive()`, `read_buf()`, plus `rprintf()`/`rsyserr()` for diagnostics and rsync allocation helpers such as `alloc_xbuf()`. Any future patch should stay within those helpers and avoid adding awkward control flow such as a new avoidable `goto`.
Prior Fixer patch note: `prior-best.patch` only adds `lib/dummy`, a build-support placeholder, and does not address the reported I/O wait signal. It should be replaced by this no-patch diagnosis unless stronger evidence is collected.
## Risks
Changing timeout, keepalive, or `select()` behavior on inferred evidence would be timing-sensitive and could regress long-running transfers, receiver/generator coordination, daemon sessions, or older protocol behavior. Because this touches timing/timeout behavior, a source patch should wait for reproducible behavior and security/availability impact analysis.
## Validation
First project-level entrypoint to try from the workspace root before any focused check: `./configure && make`.
If that fails because generated files or bundled dependency files are missing, record the exact command and failure reason, then try the narrowest reproducible compile for the implicated I/O code.
Bounded independent evidence attempt before editing: build or use rsync for a small local transfer under `strace -f -ttT -e trace=select,pselect6,read,write` and check whether waits block for real time or return immediately in a tight loop. This can support the diagnosis, but should not be called `reproduced` unless it actually shows the failing near-zero wakeup pattern.
## Patch Pass
Subject: rsync: leave select wait finding as diagnosis
## Commit Message
No source change is proposed. The collected profiler, `strace`, and `/proc` evidence points to rsync sleeping in its normal `select()`-based I/O wait path, not to a confirmed busy-poll loop. A timing/timeout source change would need reproduced evidence before it is upstream-ready.
## Evidence Confidence
inferred
## Issue Connection
The collected signal is a Fixer runaway-process finding for `rsync --server ... --timeout=300 ...`. The supporting data shows `State: S (sleeping)`, `wchan: poll_schedule_timeout`, total CPU around `0.2%`, and one `pselect6` call that blocked for about `2.49s` before an 8-byte `read`.
The likely root cause is a false-positive busy-poll classification of normal blocking I/O wait. In rsync, this maps to the `io.c` I/O helpers: `perform_io()` and `safe_read()` wait in `select()`, while `set_io_timeout()`, `check_timeout()`, `maybe_send_keepalive()`, and `read_buf()` manage timeout and keepalive behavior. Local diagnostics use `rprintf()`/`rsyserr()`, and allocation helpers such as `alloc_xbuf()` are used nearby. I found `README.md` and `SECURITY.md`; no `CONTRIBUTING`, `HACKING`, `README-hacking`, `docs/`, or `dev-docs/` style guide was present.
I made no source change. The previous Fixer patch only added `lib/dummy`, which is a build placeholder and does not address the reported I/O wait signal, so it should not be carried forward as an issue fix. The expected effect is to avoid an upstream-unready timing/timeout patch until a longer trace or symbolized stack shows an actual non-blocking loop.
## Git Add Paths
None
## Validation
`./configure && make` failed from the workspace root before `make` ran. Exact blocker: `config.status: error: cannot find input file: 'zlib/dummy.in'`; this Debian source snapshot does not contain `zlib/dummy.in` while generated configure output still wants it.
Focused compile attempt: `gcc -DHAVE_CONFIG_H -I. -Ilib -c io.c -o /tmp/rsync-io.o` failed because `config.h` was not generated after `config.status` failed.
Independent reproduction attempt: `strace -f -ttT -e trace=select,pselect6,read,write -o /tmp/rsync-fixer.strace /usr/bin/rsync -a --timeout=1 /tmp/rsync-fixer-src/ /tmp/rsync-fixer-dst/` was blocked by ptrace permissions: `PTRACE_TRACEME: Operation not permitted` and `ptrace(PTRACE_SEIZE, 7): Operation not permitted`.
Smoke check without tracing: `/usr/bin/rsync -a --timeout=1 /tmp/rsync-fixer-src/ /tmp/rsync-fixer-dst/` completed with `rsync_rc=0`; `/usr/bin/time` reported `elapsed=0.05 user=0.00 sys=0.00 cpu=5%`, and `cmp` returned `0`.
## Review Pass 1
RESULT: ok
No blocking review findings. The author left no source diff, classified the evidence as `inferred`, and did not present the profiler/trace signal as a reproduced rsync bug. That is appropriate because the evidence shows a sleeping process in `poll_schedule_timeout`, low CPU, and a `pselect6` call that blocked for real time.
The validation is acceptable for a no-patch diagnosis: `./configure && make` was attempted from the workspace root and the exact `zlib/dummy.in` blocker was reported, followed by a focused `io.c` compile attempt and a bounded runtime reproduction attempt that was blocked by ptrace permissions. The response also names the relevant rsync I/O helpers and local docs, and the workspace currently has no source diff.
Diff
--- a/lib/dummy 1970-01-01 04:00:00.000000000 +0400
+++ b/lib/dummy 2026-05-26 21:23:03.025974720 +0400
@@ -0,0 +1,2 @@
+This is a dummy file to ensure that the lib directory gets created
+by configure when a VPATH is used.