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. 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.
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. 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 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` as a likely busy-poll runaway, but the collected evidence does not currently support a source patch. The sampled process was in `pselect6()` with about a 60-second timeout, `State: S (sleeping)`, `wchan: poll_schedule_timeout`, only one traced syscall over 5 seconds, and total CPU around 0.3% across 8 rsync processes. That matches rsync’s normal timeout-driven IO wait in `io.c`, not a demonstrated tight loop.
## Evidence Confidence
inferred
## Proposed Subject
No source patch yet: diagnose the Fixer signal as insufficient for an upstream rsync busy-poll fix, and collect bounded confirmation before any edit.
## Patch Plan
No files should be edited in this pass. The likely implicated code is rsync’s IO loop in `io.c`: `perform_io()` calls `select()` with `select_timeout`, `set_io_timeout()` caps it at `SELECT_TIMEOUT`, and `check_timeout()`/`maybe_send_keepalive()` implement rsync’s keepalive behavior.
Maintainer conventions/helpers found: rsync uses local wrappers and conventions such as `rprintf()`, `rsyserr()`, `exit_cleanup()`, `msleep()`, `maybe_send_keepalive()`, `perform_io()`, and `set_io_timeout()` for IO, logging, and timeout handling. Any future patch should stay inside those helpers and avoid awkward control flow such as new avoidable `goto`s.
No prior Fixer patch was present in this workspace; it matches the original Debian source except `.git`, `.agents`, and `.codex`.
If additional evidence shows an actual zero-timeout or repeated immediate `select()` wakeup, the patch target would be a narrow change in `io.c` around `extra_flist_sending_enabled` or timeout bookkeeping. Based on the current evidence, proposing that now would be speculative.
## Risks
The main risk is patching normal rsync behavior and regressing long-running transfers. The observed `pselect6(... {tv_sec=59, ...})` is expected for `--timeout=300`, because rsync caps periodic IO wakeups at about 60 seconds. Reducing or altering that behavior without a real reproducer could increase needless wakeups or break keepalive semantics.
## Validation
Before reporting any focused compile, try the project entrypoint from the workspace root:
```sh
./configure && make
```
Then run a bounded independent signal check, not as proof of the reported bug but to verify whether a cheap local transfer shows repeated immediate polling:
```sh
timeout 20s strace -f -tt -T -e trace=select,pselect6 ./rsync --timeout=300 --partial --numeric-ids --info=STATS2 -a ./README.md /tmp/rsync-fixer-check/
```
A real source patch should only proceed if this or another bounded reproducer shows rapid repeated zero-duration `select`/`pselect6` wakeups or measurable CPU spin. Current evidence only supports a no-patch diagnosis.
## Patch Pass
Subject: No patch: rsync pselect evidence is inconclusive
## Commit Message
No source patch is proposed. The collected trace points at rsync waiting in its normal timeout-driven IO loop, not at a demonstrated busy-poll loop.
## Evidence Confidence
inferred
## Issue Connection
Fixer reported a likely busy-poll runaway, but the collected signal is contradictory: the sampled process was `S (sleeping)`, `wchan` was `poll_schedule_timeout`, strace captured one `pselect6()` over 5 seconds with about 59 seconds left in the timeout, and total CPU was about 0.3% across 8 rsync processes.
The cautious code-level inference is that this is rsync’s normal IO wait path. In `io.c`, `set_io_timeout()` caps periodic waits at `SELECT_TIMEOUT` and `perform_io()` passes that timeout to `select()`, while `check_timeout()` and `maybe_send_keepalive()` handle timeout/keepalive behavior. A 59-second `pselect6()` timeout is consistent with that design for `--timeout=300`.
I followed the saved plan and made no source changes. The expected effect is no behavioral change: this avoids sending an upstream patch that could regress long-running transfers without evidence of immediate repeated wakeups. Project guidance found `README.md`; no `CONTRIBUTING`, `HACKING`, `README-hacking`, `docs/`, or `dev-docs/` were present. Relevant local helpers/conventions include `perform_io()`, `set_io_timeout()`, `check_timeout()`, `maybe_send_keepalive()`, `rprintf()`, `rsyserr()`, and `exit_cleanup()`.
## Git Add Paths
None
## Validation
`./configure && make` was attempted from the workspace root. It failed during configure before compilation:
```text
config.status: error: cannot find input file: 'zlib/dummy.in'
```
The Debian packaging notes this source layout expects generated placeholder directories/files for bundled libraries, and this environment also lacks `libpopt` development files, so a clean project build was blocked.
Bounded independent reproduction attempt:
```sh
timeout 20s strace -f -tt -T -e trace=select,pselect6 /usr/bin/rsync --timeout=300 --partial --numeric-ids --info=STATS2 -a ./README.md /tmp/rsync-fixer-check-89917/
```
That was blocked by ptrace permissions:
```text
PTRACE_TRACEME: Operation not permitted
ptrace(PTRACE_SEIZE, 5): Operation not permitted
```
Fallback smoke check:
```sh
/usr/bin/time -f 'elapsed=%e status=%x' timeout 20s /usr/bin/rsync --timeout=300 --partial --numeric-ids --info=STATS2 -a ./README.md /tmp/rsync-fixer-check-89917/
```
It completed successfully in `elapsed=0.04` with `status=0`; it did not reproduce the collected busy-poll signal.
## Review Pass 1
RESULT: ok
No source diff is present, and the latest author response correctly treats the profiler/strace signal as `inferred` rather than a confirmed rsync bug. The no-patch diagnosis is consistent with the evidence: sleeping process state, `poll_schedule_timeout`, one `pselect6()` with a long timeout, and low aggregate CPU.
The response includes the required evidence classification, avoids inventing a reproducer, names the relevant rsync IO helpers/conventions, reports the project-level `./configure && make` blocker exactly, and documents the blocked bounded `strace` reproduction attempt plus a fallback smoke check.
Diff
--- a/lib/dummy 1970-01-01 04:00:00.000000000 +0400
+++ b/lib/dummy 2026-05-13 03:13:31.539299969 +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.