[New-bugs-announce] [issue45298] SIGSEGV when access a fork Event in a spawn Process

Keming report at bugs.python.org
Sun Sep 26 21:33:14 EDT 2021

New submission from Keming <kemingy94 at gmail.com>:

Code to trigger this problem:

import multiprocessing as mp
from time import sleep

def wait_for_event(event):
    while not event.is_set():

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

if __name__ == "__main__":

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 at python
components: Documentation
messages: 402687
nosy: docs at python, kemingy
priority: normal
severity: normal
status: open
title: SIGSEGV when access a fork Event in a spawn Process
type: crash

Python tracker <report at bugs.python.org>

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