gh-108724: Fix _PySemaphore_Wait call during thread deletion #116483
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In general, when `_PyThreadState_GET()` is non-NULL then the current thread is "attached", but there is a small window during `PyThreadState_DeleteCurrent()` where that's not true: tstate_delete_common is called when the thread is detached, but before current_fast_clear(). This updates _PySemaphore_Wait() to handle that case.
colesbury force-pushed the gh-108724-sema-wait branch from e4aa866 to 6a6ca9e Compare colesbury changed the title 
ericsnowcurrently approved these changes Mar 8, 2024
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LGTM
I have one very minor comment about the applicability of the PyEval_ReleaseThread() call. Feel free to address it (or not) how you think makes sense.
As to the motivation for this PR, should we aim for eliminating the small window you described in PR description? It vaguely feels like something is our of whack with that.
Co-authored-by: Eric Snow <ericsnowcurrently@gmail.com>
Yeah, I'll put up another PR that does that as well. |
adorilson pushed a commit to adorilson/cpython that referenced this pull request Mar 25, 2024
…ython#116483) In general, when `_PyThreadState_GET()` is non-NULL then the current thread is "attached", but there is a small window during `PyThreadState_DeleteCurrent()` where that's not true: tstate_delete_common() is called when the thread is detached, but before current_fast_clear(). Co-authored-by: Eric Snow <ericsnowcurrently@gmail.com>
diegorusso pushed a commit to diegorusso/cpython that referenced this pull request Apr 17, 2024
…ython#116483) In general, when `_PyThreadState_GET()` is non-NULL then the current thread is "attached", but there is a small window during `PyThreadState_DeleteCurrent()` where that's not true: tstate_delete_common() is called when the thread is detached, but before current_fast_clear(). Co-authored-by: Eric Snow <ericsnowcurrently@gmail.com>
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In general, when
_PyThreadState_GET()is non-NULL then the current thread is "attached", but there is a small window duringPyThreadState_DeleteCurrent()where that's not true:tstate_delete_common()is called when the thread is detached, but before current_fast_clear().This updates
_PySemaphore_Wait()to handle that case.