myxce/.wolf/bugs/bug-1693.md
Rongsong Shen d26ff8870d
feat(buglog): one Markdown record per bug, checked against a record standard
The buglog was one 27K-line JSON file whose fields covered only symptom,
root cause and fix, as free text: 2% of entries named the code version a
bug was found on, 12% the build profile, 36% a way to reproduce, and 58% of
the file was OpenWolf hook auto-detections ("Missing guard clause",
"Function not marked async" on .md files).

- .claude/skills/buglog/bug-record.md: the record standard. Eight
  sections (Summary as the title, Description, Environment, Reproduction;
  Root cause, Fix, Verification, References once fixed), each with the
  content it must contain -- e.g. Environment needs the OS, the libc the
  failing binary loads (from its ELF interpreter: glibc 2.42 in the nix
  shell vs 2.40 on the host), toolchain, build profile and commit.
- .wolf/bugs/<id>.md: 500 records migrated from buglog.json; every field
  verified to round-trip. They carry legacy: true and an explicit "not
  recorded" where the old log had no such field; component derived from
  file paths, severity from keywords (else unknown), fix_commits from
  hashes in status_note/fix that git resolves (91 of 463 fixed).
- .wolf/buglog-archive.json: the 710 hook auto-detections, verbatim.
- .wolf/buglog.json is now an index generated from the records, keeping
  the fields OpenWolf's hooks and `openwolf bug search` read.
- scripts/buglog.py rewritten: new (template + Environment collected from
  the machine and --binary), check, status (refuses a status the record
  doesn't support; fixed needs Root cause, Fix, Verification and
  --commit hashes git resolves), note, recur, set, show, list, triage,
  env, index. 29 unittest cases in scripts/tests/test_buglog.py.
- scripts/git-hooks/pre-commit runs `check --staged`: incomplete staged
  records, a legacy record hand-changed to fixed without the fix-time
  sections, a new record claiming legacy: true, or a stale index refuse
  the commit.
- scripts/gitea-sync.py reads the records: issue body = the record's
  sections plus linked fix commits (origin remote, GITEA_COMMIT_REPO to
  override), and a body hash so an issue's text is refreshed when the
  record changes.
- bug-1866 rewritten to the full standard as the worked example.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
2026-09-28 03:40:11 +00:00

38 lines
5.4 KiB
Markdown

---
id: "bug-1693"
status: "fixed"
status_updated: "2026-09-24"
status_note: ""
component: "controller"
severity: "hang"
timestamp: "2026-08-25T14:05:00Z"
last_seen: "2026-09-19T09:00:00Z"
occurrences: 1
files: ["src/controller/cluster.c", "src/controller/sched.c", "src/controller/job.c", "src/controller/worker.c", "src/controller/include/cluster.h"]
tags: ["controller", "decision-log-fidelity", "cluster.c", "sched.c", "job.c", "worker.c", "OPCode_schedAdmin", "on_fetchfile", "handle_scheduler_leave", "handle_worker_leave", "fail-loud", "condvar-signal", "reply-wait-timeout", "xce-audit-invariants", "ha-async-io"]
related: ["bug-646", "bug-648", "bug-650"]
legacy: true
---
# bug-1693: Invariant audit (Decision Log fidelity dimension) found two violations of the recorded Decision…
## Description
Invariant audit (Decision Log fidelity dimension) found two violations of the recorded Decision Log entry "No client reply-wait timeout as a fix for a hung request -- fail loud at the real transport/source instead of masking with a deadline backstop": (1) OPCode_schedAdmin's forward-and-block-for-reply (cluster.c) blocks up to SCHEDADMIN_TIMEOUT_MS=5000ms via pthread_cond_timedwait, but handle_scheduler_leave() (sched.c) -- the actual scheduler-disconnect handler -- only ever nulled c->sched.ep; it never signalled the pending waiter, so a scheduler disconnect mid-wait could only ever be observed at the full 5s deadline. (2) on_fetchfile's identical proxy pattern (job.c, 10s pthread_cond_timedwait) had the same gap: handle_worker_leave() (worker.c) only ever nulled w->ep, never woke a pending fetchfile waiter proxied to that worker.
## Environment
_Not recorded (migrated from buglog.json)._
## Reproduction
_Not recorded (migrated from buglog.json)._
## Root cause
Both sites already had a working signal function used on the SUCCESS path (schedadmin_signal() in cluster.c, fetchfile_signal() in job.c, both wake the pending condvar wait when a real reply arrives) -- but the corresponding DISCONNECT handlers (handle_scheduler_leave/handle_worker_leave) were never wired to call them. cluster.c's own OPCode_schedAdmin comment explicitly documents schedAdmin as mirroring on_fetchfile's proxy pattern, confirming this was one shared, repeated design mistake copied into both sites, not two independent bugs. The timeout backstop was therefore the SOLE failure-detection mechanism for a mid-wait disconnect at both sites, exactly what the Decision Log entry (itself the outcome of bug-646/648/650's original fail-loud fix) forbids.
## Fix
Kept the timeout as a defensive backstop (per the Decision Log's exact wording: the rule is about not relying SOLELY on a timeout, not removing timeouts) and added an immediate-wake path on disconnect at both sites, mirroring bug-646/648/650's original fail-loud precedent. schedAdmin site: new int schedadmin_signal_disconnect(void) (cluster.c) -- a thin wrapper calling the existing static schedadmin_signal(-ECONNRESET, NULL) -- declared extern in cluster.h; handle_scheduler_leave() (sched.c) now calls it BEFORE acquiring c->sched.lock (calling it after would deadlock, since the OPCode_schedAdmin dispatch case holds c->sched.lock for its entire forward+wait duration; schedadmin_signal_disconnect() itself never touches c->sched.lock, only g_schedadmin_mu + the pending slot's own mu, so no new lock-ordering hazard). cluster.c's post-wait dispatch gained a new got_status==-ECONNRESET branch relaying a structured SchedAdminReply{error="scheduler disconnected"}, distinguishable from both the immediate "scheduler not connected" rejection and the deadline's "request timeout". fetchfile site: fetchfile_pending_t (job.c) gained a worker_t* worker field (set in on_fetchfile() while still holding the worker's read lock, before fetchfile_register()); new void fetchfile_signal_worker_disconnect(worker_t*) (job.c, declared extern in cluster.h) walks g_fetchfile_list under g_fetchfile_mu and signals every pending entry matching the disconnected worker with status=-ECONNRESET (unlike fetchfile_signal, which is keyed by a single jobid, more than one fetchfile request can be in flight against the same worker); handle_worker_leave() (worker.c) calls it right after nulling w->ep (no lock-ordering constraint there, since on_fetchfile's wait never holds any worker_t lock). Hidden fan-out cost discovered only at link time (matches this project's established pattern for this class of change): controller_unit_test does not link the real sched.c at all (test_config_repl.c already provides its own no-op handle_scheduler_leave() stub, to avoid an unrelated on_scheduler_join()/notify() link collision with other files in that binary) -- so the primary schedAdmin regression test drives schedadmin_signal_disconnect() directly (the real, unmodified, unstubbed production function in cluster.c) rather than through handle_scheduler_leave(), and a SEPARATE small spy-based test was added in test_sched_worker_change.c (which DOES link the real sched.c) proving handle_scheduler_leave() itself calls schedadmin_signal_disconnect() exactly once, before clearing c->sched.ep. Also had to add a one-line link-satisfying schedadmin_signal_disconnect() stub to test_job_array_sched_push.c and test_sched_worker_change.c (the two standalone binaries that link sched.c without cluster.c), mirroring their existing check_worker_() stub precedent.
## Verification
_Not recorded (migrated from buglog.json)._
## References
- Related: bug-646, bug-648, bug-650