anchao opened a new pull request, #21065:
URL: https://github.com/apache/nuttx/pull/21065
## Summary
Fix a race in the `sigtimedwait()` wait path where a matching signal could
remain pending while the waiting task goes to sleep.
`sigtimedwait()` publishes `sigwaitmask` before calling `nxsig_clockwait()`.
If a matching signal is queued after that publication but before the task is
moved to `TSTATE_WAIT_SIG`, the signal can remain pending while the task
still
blocks waiting for it.
This change rechecks the task's pending signal set inside
`nxsig_clockwait()`
while interrupts are disabled. If a pending signal matches `sigwaitmask`, it
is
removed from the pending queue, copied into `sigunbinfo`, and returned
immediately instead of blocking the task.
## Impact
This fixes a signal wait race that could cause `sigtimedwait()` to sleep
even
though a waited-for signal is already pending.
Expected impact:
- prevents missed wakeups in the `sigtimedwait()` path
- preserves normal blocking behavior when no matching signal is pending
- consumes and reports the lowest-numbered matching pending signal
- avoids changing behavior when signals are disabled
- no API, ABI, build-system, documentation, or security impact is expected
## Testing
sim/nsh
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