…t thread holds it (
pythonGH-118745)
`drop_gil()` assumes that its caller is attached, which means that the current
thread holds the GIL if and only if the GIL is enabled, and the enabled-state
of the GIL won't change. This isn't true, though, because `detach_thread()`
calls `_PyEval_ReleaseLock()` after detaching and
`_PyThreadState_DeleteCurrent()` calls it after removing the current thread
from consideration for stop-the-world requests (effectively detaching it).
Fix this by remembering whether or not a thread acquired the GIL when it last
attached, in `PyThreadState._status.holds_gil`, and check this in `drop_gil()`
instead of `gil->enabled`.
This fixes a crash in `test_multiprocessing_pool_circular_import()`, so I've
reenabled it.
(cherry picked from commit
be1dfcc)
Co-authored-by: Brett Simmers <swtaarrs@users.noreply.github.com>
drop_gil() assumes that its caller is attached, which means that the current
thread holds the GIL if and only if the GIL is enabled, and the enabled-state
of the GIL won't change. This isn't true, though, because detach_thread()
calls _PyEval_ReleaseLock() after detaching and
_PyThreadState_DeleteCurrent() calls it after removing the current thread
from consideration for stop-the-world requests (effectively detaching it).
Fix this by remembering whether or not a thread acquired the GIL when it last
attached, in PyThreadState._status.holds_gil, and check this in drop_gil()
instead of gil->enabled.
This fixes a crash in test_multiprocessing_pool_circular_import(), so I've
reenabled it.
(cherry picked from commit be1dfcc)
Co-authored-by: Brett Simmers swtaarrs@users.noreply.github.com