Message365173
At fork, Python calls PyOS_AfterFork_Child() in the child process which indirectly calls _PyThreadState_DeleteExcept() whichs calls release_sentinel() of the thread which releases the thread state lock (threading.Thread._tstate_lock).
Problem: using a lock after fork is unsafe and can crash.
That's exactly what happens randomly on AIX when stressing ThreadJoinOnShutdown.test_reinit_tls_after_fork() of test_threading:
https://bugs.python.org/issue40068#msg365031
There are different options to solve this issue:
* Reset _tstate_lock before using it... not sure that it's worth it, since we are going to delete the threading.Thread object with its _tstate_lock object anymore. After calling fork, the child process has exactly 1 thread: all other threads have been removed.
* Modify release_sentinel() to not use the lock: avoid PyThread_release_lock() call. |
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2020-03-27 17:16:55 | vstinner | set | recipients:
+ vstinner |
2020-03-27 17:16:55 | vstinner | set | messageid: <1585329415.65.0.534969367772.issue40092@roundup.psfhosted.org> |
2020-03-27 17:16:55 | vstinner | link | issue40092 messages |
2020-03-27 17:16:55 | vstinner | create | |
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