Rongsong Shen
d26ff8870d
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>
39 lines
3.9 KiB
Markdown
39 lines
3.9 KiB
Markdown
---
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id: "bug-1771"
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status: "fixed"
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status_updated: "2026-09-25"
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status_note: "1ecd348f"
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component: "scheduler"
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severity: "crash"
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timestamp: "2026-09-04T00:00:00Z"
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last_seen: "2026-09-19T09:00:00Z"
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occurrences: 1
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files: []
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tags: ["scheduler", "fcfs", "legacy-plugin", "null-deref", "asan", "pre-existing", "severity-low", "scheduler-allocation-discovery", "task-5.3"]
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related: []
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fix_commits: ["1ecd348f"]
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legacy: true
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---
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# bug-1771: ASAN SEGV (READ of address 0x0) in fcfs_del_job() (src/scheduler/src/plugins/fcfs.c:318…
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## Description
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ASAN SEGV (READ of address 0x0) in fcfs_del_job() (src/scheduler/src/plugins/fcfs.c:318, `job->queue->name`), reached via fcfs_commit() <- plugin_commit_decision() <- sched_commit_decision() <- commit_decision() <- sched_allocator(), the very first time a real DISPATCH decision was committed through the real, live sched_allocator() thread in this test directory. Discovered live during scheduler-allocation task 5.3's own end-to-end integration test construction (test_parjob_e2e_multislot.c) -- full ASAN backtrace captured.
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## Environment
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_Not recorded (migrated from buglog.json)._
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## Reproduction
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_Not recorded (migrated from buglog.json)._
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## Root cause
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CONFIRMED via direct code read and the live ASAN backtrace. plugin_commit_decision() (src/scheduler/src/plugin.c:442-475) unconditionally fans a committed decision out to EVERY registered plugin's own `.hooks.commit_hook`, regardless of which plugin is the currently-ACTIVE job picker -- this includes the legacy 'xce_sched_fcfs' plugin (src/scheduler/src/plugins/fcfs.c), still registered alongside the modern default 'builtin_fcfs' by sched_register_plugins() (scheduler.c) even when it is never the resolved picker. fcfs_commit() (fcfs.c:326-337) calls fcfs_del_job(plugin, decision->u.alloc->jobid) for every XCE_DECISION_DISPATCH, and fcfs_del_job() (fcfs.c:303-324) unconditionally dereferences `job->queue->name` with no NULL check on `job->queue` -- sched_get_queue() (core.c:257-271) is get-ONLY (never auto-creates), so any job whose xce_sched_job_t.queue is NULL (i.e. its submitted queue name was never registered via a real QUEUE_UPDATE/CONFIG_PUSH event before the job reached DISPATCH) crashes this unrelated legacy plugin's own housekeeping, even though that plugin never elected or tracked the job at all. Every prior real-scheduler_srcs test in this directory that reaches a real sched_commit_decision() (test_scheduler_cache_dispatch.c, test_scheduler_cache_dispatch_compound.c, test_snapshot_load_allocator_regression.c) only ever produces PEND decisions (fcfs_commit()'s `default: break;` branch, never touching job->queue), so this NULL-deref had never been triggered before. Not reachable in real production as the system stands today (a real job's queue is always registered via controller-pushed config before any job can target it), but IS a genuine, real, unguarded NULL dereference in a code path that runs unconditionally for every real DISPATCH decision regardless of test/production context.
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## Fix
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NOT FIXED -- discovered during scheduler-allocation task 5.3's end-to-end test construction (2026-09-04). test_parjob_e2e_multislot.c's own fixture was corrected instead (added a real XCE_CORE_EVENT_QUEUE_UPDATE push registering the job's queue before the JOBS_PUSH event, matching real production sequencing where queues are always configured before any job can target them) -- this is the correct fix for that specific test, not a production defect this task's own boundary covers. The underlying hardening gap (fcfs_del_job() missing a `job->queue == NULL` guard before dereferencing `job->queue->name`) remains open; recommended minimal fix for a dedicated follow-up: `if ((job == NULL) || (job->queue == NULL)) { return 0; }` in fcfs_del_job(), mirroring the function's own existing `if (job == NULL) { return 0; }` early-return style.
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## Verification
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_Not recorded (migrated from buglog.json)._
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## References
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_Not recorded (migrated from buglog.json)._
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