gh-132969: Fix error/hang when shutdown(wait=False) and task exited abnormally by ogbiggles · Pull Request #133222 · python/cpython · GitHub

When shutdown is called with wait=False, the executor thread keeps running even after the ProcessPoolExecutor's state is reset. The executor then tries to replenish the worker processes pool resulting in an error and a potential hang when it comes across a worker that has died. Fixed the issue by having _adjust_process_count() return without doing anything if the ProcessPoolExecutor's state has been reset.

Added unit tests to validate two scenarios:
max_workers < num_tasks (exception)
max_workers > num_tasks (exception + hang)

Issue: ProcessPoolExecutor raises exception or hangs the process when shutdown(wait=False) and worker throws exception #132969

…ted abnormally When shutdown is called with wait=False, the executor thread keeps running even after the ProcessPoolExecutor's state is reset. The executor then tries to replenish the worker processes pool resulting in an error and a potential hang when it comes across a worker that has died. Fixed the issue by having _adjust_process_count() return without doing anything if the ProcessPoolExecutor's state has been reset. Added unit tests to validate two scenarios: max_workers < num_tasks (exception) max_workers > num_tasks (exception + hang)

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… into origin/main Skip forkserver-dependent test on Windows

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@hugovk: If this is indeed a blocker for the beta, +1 for me -- it shouldn't break anything.
For a proper review, I'd need more time to familiarize myself with this part of the code. (@gpshead, should I?)

But, as week-old issue that affects 3.12+, I think it's OK to defer it.

@itamaro: Did you intend this to block the beta?

Did you intend this to block the beta?

Should have said it here, not only in Discord :)
I wasn't sure whether this should block the release, so added the tag to make sure someone at least takes a look, considering beta 1 is imminent!

Thanks all, it's been looked at and sounds like it can wait, so let's defer it.

…nittest.skipIf annotation to skip test on win32, add some more comments

… into origin/main

…g to "spawn"

…indows

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Thanks @ogbiggles for the PR, and @encukou for merging it 🌮🎉.. I'm working now to backport this PR to: 3.13.
🐍🍒⛏🤖

Thanks @ogbiggles for the PR, and @encukou for merging it 🌮🎉.. I'm working now to backport this PR to: 3.14.
🐍🍒⛏🤖

…ited abnormally (pythonGH-133222) When shutdown is called with wait=False, the executor thread keeps running even after the ProcessPoolExecutor's state is reset. The executor then tries to replenish the worker processes pool resulting in an error and a potential hang when it comes across a worker that has died. Fixed the issue by having _adjust_process_count() return without doing anything if the ProcessPoolExecutor's state has been reset. Added unit tests to validate two scenarios: max_workers < num_tasks (exception) max_workers > num_tasks (exception + hang) (cherry picked from commit 598aa7c) Co-authored-by: Ajay Kamdar <140011370+ogbiggles@users.noreply.github.com>

GH-135343 is a backport of this pull request to the 3.13 branch.

…ited abnormally (pythonGH-133222) When shutdown is called with wait=False, the executor thread keeps running even after the ProcessPoolExecutor's state is reset. The executor then tries to replenish the worker processes pool resulting in an error and a potential hang when it comes across a worker that has died. Fixed the issue by having _adjust_process_count() return without doing anything if the ProcessPoolExecutor's state has been reset. Added unit tests to validate two scenarios: max_workers < num_tasks (exception) max_workers > num_tasks (exception + hang) (cherry picked from commit 598aa7c) Co-authored-by: Ajay Kamdar <140011370+ogbiggles@users.noreply.github.com>

GH-135344 is a backport of this pull request to the 3.14 branch.

…xited abnormally (GH-133222) (GH-135344) gh-132969: Fix error/hang when shutdown(wait=False) and task exited abnormally (GH-133222) When shutdown is called with wait=False, the executor thread keeps running even after the ProcessPoolExecutor's state is reset. The executor then tries to replenish the worker processes pool resulting in an error and a potential hang when it comes across a worker that has died. Fixed the issue by having _adjust_process_count() return without doing anything if the ProcessPoolExecutor's state has been reset. Added unit tests to validate two scenarios: max_workers < num_tasks (exception) max_workers > num_tasks (exception + hang) (cherry picked from commit 598aa7c) Co-authored-by: Ajay Kamdar <140011370+ogbiggles@users.noreply.github.com>

…xited abnormally (GH-133222) (GH-135343) gh-132969: Fix error/hang when shutdown(wait=False) and task exited abnormally (GH-133222) When shutdown is called with wait=False, the executor thread keeps running even after the ProcessPoolExecutor's state is reset. The executor then tries to replenish the worker processes pool resulting in an error and a potential hang when it comes across a worker that has died. Fixed the issue by having _adjust_process_count() return without doing anything if the ProcessPoolExecutor's state has been reset. Added unit tests to validate two scenarios: max_workers < num_tasks (exception) max_workers > num_tasks (exception + hang) (cherry picked from commit 598aa7c) Co-authored-by: Ajay Kamdar <140011370+ogbiggles@users.noreply.github.com>

…ited abnormally (pythonGH-133222) When shutdown is called with wait=False, the executor thread keeps running even after the ProcessPoolExecutor's state is reset. The executor then tries to replenish the worker processes pool resulting in an error and a potential hang when it comes across a worker that has died. Fixed the issue by having _adjust_process_count() return without doing anything if the ProcessPoolExecutor's state has been reset. Added unit tests to validate two scenarios: max_workers < num_tasks (exception) max_workers > num_tasks (exception + hang)

bedevere-app Bot added the awaiting review label Apr 30, 2025

bedevere-app Bot mentioned this pull request Apr 30, 2025

ProcessPoolExecutor raises exception or hangs the process when shutdown(wait=False) and worker throws exception #132969

Closed

📜🤖 Added by blurb_it.

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ogbiggles mentioned this pull request Apr 30, 2025

[3.12] gh-132969: Fix exception/hang shutdown(wait=False) and a task exited abnormally #133220

Closed

blurb-it Bot and others added 4 commits April 30, 2025 16:48

gh-132969 Skip forkserver-dependent test on Windows

0938eeb

Merge branch 'origin/main' of github.com:ogbiggles/cpython-fix-132969…

dbc0ba8

… into origin/main Skip forkserver-dependent test on Windows

gh-132969 Skip forkserver dependent tests on Windows

99ab321

Merge branch 'main' into origin/main

fe3650c

ZeroIntensity added the topic-multiprocessing label May 4, 2025