bpo-42350: Fix Thread._reset_internal_locks() (GH-23268)
Fix the threading.Thread class at fork: do nothing if the thread is
already stopped (ex: fork called at Python exit). Previously, an
error was logged in the child process.
(cherry picked from commit 5909a494cd3ba43143b28bd439773ed85a485dfc)
Co-authored-by: Victor Stinner <vstinner@python.org>
diff --git a/Lib/threading.py b/Lib/threading.py
index ab29db7..d96d99a 100644
--- a/Lib/threading.py
+++ b/Lib/threading.py
@@ -826,8 +826,12 @@
# they may be in an invalid state leading to a deadlock or crash.
self._started._at_fork_reinit()
if is_alive:
- self._tstate_lock._at_fork_reinit()
- self._tstate_lock.acquire()
+ # bpo-42350: If the fork happens when the thread is already stopped
+ # (ex: after threading._shutdown() has been called), _tstate_lock
+ # is None. Do nothing in this case.
+ if self._tstate_lock is not None:
+ self._tstate_lock._at_fork_reinit()
+ self._tstate_lock.acquire()
else:
# The thread isn't alive after fork: it doesn't have a tstate
# anymore.