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>
38 lines
2.7 KiB
Markdown
38 lines
2.7 KiB
Markdown
---
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id: "bug-1077"
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status: "fixed"
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status_updated: "2026-09-24"
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status_note: ""
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component: "lib"
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severity: "crash"
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timestamp: "2026-06-24T17:30:00.000Z"
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last_seen: "2026-09-19T09:00:00Z"
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occurrences: 1
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files: ["src/lib/xcectx.c"]
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tags: ["asan", "use-after-return", "union-type-confusion", "ha", "failover", "ctrlstatus", "libxce", "memory-safety", "regression-61e1391", "VERIFIED"]
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related: ["bug-646", "bug-1060", "bug-1067"]
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legacy: true
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---
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# bug-1077: AddressSanitizer: SEGV / stack-use-after-return in free_CtrlStatus (lib/controller.capnp.c:11638)…
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## Description
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AddressSanitizer: SEGV / stack-use-after-return in free_CtrlStatus (lib/controller.capnp.c:11638) via handle_reply -> free_CtrlStatus_ptr (lib/xcectx.c:91) on `ctrlstatus` after failover; READ derefs the dead-stack `getreply` of xce_get_with_condition (xceapi.c)
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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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ctx->reply.u is an UNTAGGED union shared across opcodes (debugmsg/get/jobid/clusterconf/ctrlstatus alias the same 8 bytes). Commit 61e1391 ('fix bug-1060 bug-1067', unrelated Raft work) added speculative free-guards `if (ctx->reply.u.ctrlstatus) free_CtrlStatus_ptr(&ctx->reply.u.ctrlstatus)` (and the clusterconf twin). A non-NULL slot does NOT imply a CtrlStatus*: a failover-aborted reslist/joblist leaves ctx->reply.u.get == &getreply (a dead STACK pointer) because xce_get_with_condition/xce_resval only NULL the slot on the success path, not the xce_get_req<0 / cbuf_get<0 early-returns. The next ctrlstatus reply (worker thread) sees the foreign non-NULL slot and free_CtrlStatus walks it -> stack-use-after-return SEGV.
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## Fix
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1) Revert the two unsafe free-guards in handle_reply (untagged union slot can never be safely freed by type) — restores prior MOVE_PTR-overwrite behavior. 2) Clear ctx->reply.u.get = NULL on ALL early-return paths of xce_get_with_condition and xce_resval (kill the dangling-stack-pointer leak at its source; also prevents a late OPCode_get reply writing through the dead stack via handle_get_reply). 3) Defense-in-depth: handle_get_reply drops a reply when ctx->reply.u.get is NULL. Regression test: test_handle_reply_ctrlstatus_does_not_free_foreign_slot (exposes xce_handle_reply, proves a foreign heap value in the shared union is not freed). VERIFIED 2026-06-24 (Opus): re-confirmed 3-layer fix present in working tree; RED proven by re-injecting the ctrlstatus free-guard -> ASan double-free at test_ctrlstatus.c:384 (free_CtrlStatus_ptr at controller.capnp.c:11892), then restored -> GREEN. Full libxce suite 291 Tests / 0 Failures / 0 ASan errors under ASAN_OPTIONS=detect_leaks=0.
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## Verification
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_Not recorded (migrated from buglog.json)._
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## References
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- Related: bug-646, bug-1060, bug-1067
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