multiprocessing Pool hangs in terminate()

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Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
25/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Stale
Tech stack
python
Domain
backend

Research direction

Start with the attached multiprocessing_hangs.py and test_multiprocessing.py files, then inspect the relevant multiprocessing Pool implementation and PR 8009. Reproduce the hang described by the attached debugging files and compare the existing test coverage. Done means the termination hang is addressed and the multiprocessing test demonstrates the corrected behavior.

Written by the indexing model from the issue text.

Description

3.7 (EOL) 3.8 (EOL) 3.9 (EOL) stdlib topic-multiprocessing type-bug
BPO 33997
Nosy @pfmoore, @pitrou, @tjguk, @zware, @zooba, @applio, @remilapeyre, @3mb3dw0rk5, @alexmojaki
PRs
  • python/cpython#8009
    		•
    Files
  • debug.trace
  • multiprocessing_hangs.py
  • test_multiprocessing.py
  • pool_terminate_snoop.txt
    		•

    Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.

    Show more details

    GitHub fields:

    assignee = None
closed_at = None
created_at = <Date 2018-06-29.12:37:53.185>
labels = ['3.7', '3.8', 'type-bug', 'library', '3.9']
title = 'multiprocessing Pool hangs in terminate()'
updated_at = <Date 2020-09-01.09:45:02.063>
user = 'https://github.com/3mb3dw0rk5'

    bugs.python.org fields:

    activity = <Date 2020-09-01.09:45:02.063>
actor = 'vstinner'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2018-06-29.12:37:53.185>
creator = '3mb3dw0rk5'
dependencies = []
files = ['47659', '48531', '48532', '48867']
hgrepos = []
issue_num = 33997
keywords = ['patch']
message_count = 6.0
messages = ['320713', '320726', '349051', '349052', '360761', '360762']
nosy_count = 10.0
nosy_names = ['paul.moore', 'pitrou', 'tim.golden', 'zach.ware', 'steve.dower', 'davin', 'remi.lapeyre', '3mb3dw0rk5', 'alexmojaki', 'paul.madden']
pr_nums = ['8009']
priority = 'normal'
resolution = None
stage = 'patch review'
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue33997'
versions = ['Python 3.7', 'Python 3.8', 'Python 3.9']

    Dominant language
    Python
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