Adds a one-run diagnostic that distinguishes "guest never called
Nt/KeSetEvent on this handle" from "signal landed but waiter wasn't
woken", for any handle named via `--trace-handles-focus`.
Parked-waiter context (project_xenia_rs_sylpheed_stage3_2026_04_29):
four worker threads block Sylpheed past `draws=0` on handles
0x1004 / 0x100c / 0x15e4 / 0x42450b5c (mr=true, sig=false). The
pre-existing audit dropped signal-attempts that targeted handles
without a primary trail, so we couldn't tell whether the producer
was unreachable in the guest or whether the signal landed but missed
its waiter.
Three changes:
* audit.rs: `HandleAudit` gains `focus: HashSet<u32>` and
`ghost_trails: HashMap<u32, GhostTrail>`. `record_signal`
auto-falls-through to a new `record_signal_attempt_ghost` when no
primary trail exists AND the handle is in `focus`. Bounded by
AUDIT_RING_CAPACITY per handle. Two new tests cover the focus
ghost-trail and no-double-record invariants.
* main.rs: new `--trace-handles-focus=<LIST>` flag (hex 0x or decimal,
comma-separated) populates `kernel.audit.focus`. Implies
`--trace-handles`. New "=== Handle audit (focus) ===" section in
`dump_thread_diagnostic` emits per-handle:
- signal_attempts (primary + ghost), waits, wakes
- merged cycle-sorted timeline (last 16)
- GuestExport / KernelInternal classification
- <AUDIT_BLIND> marker when waiter_count > 0 but the audit
saw no waits (i.e. waiter parked via a non-audit path —
CS / spinlock / DPC).
- DIAGNOSIS conclusion that selects between five branches.
* `cmd_check` passes None for focus → goldens unaffected.
Empirical run output at -n 500M lockstep with
`--trace-handles-focus=0x1004,0x100c,0x15e4,0x42450b5c`:
handle=0x00001004 kind=Event/Manual waiters=1 signaled=false
signal_attempts=0 (primary=0, ghost=0)
waits=1 wakes=0
created cycle=0 tid=1 lr=0x824a9f6c src=NtCreateEvent
=> producer is a missing kernel signal source
(or BST-paradox upstream)
... (same shape for 0x100c, 0x15e4)
handle=0x42450b5c kind=<UNCREATED> waiters=1 signal_attempts=0
waits=0 wakes=0 <AUDIT_BLIND>
=> waiter parked via non-audited path
Conclusion: hypothesis (A) confirmed for all 4 handles. Producer is
NOT a wake/eligibility bug — it is a genuinely missing kernel signal
source. The 3 Event/Manual handles share a creator
(lr=0x824a9f6c, tid=1) and the same wait-call wrapper at
lr=0x824ac578 — these are 3 worker threads all parked on
"work-available" notifications that never come.
Verification:
* cargo test --workspace --release: 558 passing (+2 new ghost-trail
tests vs prior 556 baseline)
* lockstep -n 100M --stable-digest: bit-identical to master HEAD
Audit IDs: KRNBUG-AUDIT-001 (closed — diagnostic instrumentation).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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