/xce-audit-invariants scheduler dimension-1/4 audit, prompted by a fresh
user-captured .replay file that still showed massive --sim-verify mismatch
volume after bug-1843's fix. Root-caused via temporary diagnostic
instrumentation against the real capture (reverted, never committed) rather
than trusting the surface symptom.
bug-1844: sim_verify_alloc_eq() (sim_verify.c) compared `instid`, a bare
per-process monotonic counter (scheduler.c's sched_get_id(), core->nextid)
stamped at allocation-build time -- not semantic content. The original
recording's counter and a fresh replay's counter have no reason to reach
the same value for "the same" dispatch. Live-verified: every DISPATCH
mismatch showed identical value/duration/resname/reserve, differing only
in instid (e.g. 826 vs 1). Dropped from the comparison, same treatment as
bug-1842's `from` exclusion.
bug-1845: sim_verify_job_preason_eq() required PEND decisions' full
host/resource reason-detail lists to match. core.h documents "simulation
isolation" as deliberate design: sim/replay never registers
core->unsatisfiable_lookup_cb, so it can never hit the unsatisfiable-cache
main.c's normal-mode branch registers. A live cache hit
(sched_pend_from_cached_reason_()) records only main_reason with zero
detail; replay always falls through to the full per-host computation and
always produces detail. Same semantic outcome (PEND, same main_reason) at
two architecturally-legitimate detail levels. Relaxed the comparator to
main_reason only. Separately verified the cache itself is sound (key is
safe within a round since capacity only decreases and the cache clears
every round) -- ruling it out as the cause of a second, still-open
divergence (bug-1846: one job genuinely dispatches one round early in
replay vs. the original recording -- a suspected resource-accounting
parity gap, not yet root-caused, logged for follow-up).
bug-1772 (previously deferred, incorrectly tagged "fixed"): re-found
independently by a dimension-4 snapshot-field-completeness audit subagent.
snapshot_build_primary_schedobj() (snapshot_load.c) never computed
resreq_fp, unlike its declared model core_build_primary_schedobj()
(core_events.c) -- every snapshot-restored job got a zeroed fingerprint,
which alloc_cache.c's cache key folds in directly alongside
user/queue/project, so two distinct restored jobs sharing those three
fields could silently share an incorrect unsatisfiable-cache verdict.
Added the same 4-field computation the live path uses.
TDD throughout: each fix has a dedicated regression test, and each was
verified via genuine red (revert fix, confirm the new test fails) then
green (restore, full 85/85 scheduler suite). Also ran three parallel
dimension audits (core I/O isolation, picker/allocator jbuf rendezvous) --
both clean, no violations found.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Rongsong Shen
fcf119b4ac