[issue45298] SIGSEGV when access a fork Event in a spawn Process
New submission from Keming <kemingy94@gmail.com>: Code to trigger this problem: ```python import multiprocessing as mp from time import sleep def wait_for_event(event): while not event.is_set(): sleep(0.1) def trigger_segment_fault(): event = mp.get_context("fork").Event() p = mp.get_context("spawn").Process(target=wait_for_event, args=(event,)) p.start() # this will show the exitcode=-SIGSEGV sleep(1) print(p) event.set() p.terminate() if __name__ == "__main__": trigger_segment_fault() ``` Accessing this forked event in a spawned process will result in a segment fault. I have found a related report: https://bugs.python.org/issue43832. But I think it's not well documented in the Python 3 multiprocessing doc. Will it be better to explicit indicate that the event is related to the start method context in the documentation? ---------- assignee: docs@python components: Documentation messages: 402687 nosy: docs@python, kemingy priority: normal severity: normal status: open title: SIGSEGV when access a fork Event in a spawn Process type: crash _______________________________________ Python tracker <report@bugs.python.org> <https://bugs.python.org/issue45298> _______________________________________
Irit Katriel <iritkatriel@gmail.com> added the comment: Which python version and system are you seeing this on? On 3.11 on a Mac I don't get a segfault but rather Process SpawnProcess-1: Traceback (most recent call last): File "/Users/iritkatriel/src/cpython/Lib/multiprocessing/process.py", line 315, in _bootstrap self.run() ^^^^^^^^^^ File "/Users/iritkatriel/src/cpython/Lib/multiprocessing/process.py", line 108, in run self._target(*self._args, **self._kwargs) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/Users/iritkatriel/src/cpython/tt.py", line 6, in wait_for_event while not event.is_set(): ^^^^^^^^^^^^^^ File "/Users/iritkatriel/src/cpython/Lib/multiprocessing/synchronize.py", line 328, in is_set with self._cond: ^^^^^^^^^^^^^^^^ File "/Users/iritkatriel/src/cpython/Lib/multiprocessing/synchronize.py", line 230, in __enter__ return self._lock.__enter__() ^^^^^^^^^^^^^^^^^^^^^^ File "/Users/iritkatriel/src/cpython/Lib/multiprocessing/synchronize.py", line 95, in __enter__ return self._semlock.__enter__() ^^^^^^^^^^^^^^^^^^^^^^^^^ OSError: [Errno 9] Bad file descriptor <SpawnProcess name='SpawnProcess-1' pid=29612 parent=29610 stopped exitcode=1> ---------- nosy: +iritkatriel _______________________________________ Python tracker <report@bugs.python.org> <https://bugs.python.org/issue45298> _______________________________________
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Irit Katriel -
Keming