[New-bugs-announce] [issue43890] Deadlock when mixing event loops and subprocesses
report at bugs.python.org
Mon Apr 19 14:36:19 EDT 2021
New submission from Thomas Buhrmann <thomas.buehrmann at gmail.com>:
When mixing code that spawns subprocesses with code that creates event loops, Python appears to deadlock.
In the attached example, when WORKERS = 16 and ASYNC_WORKERS = 8, Python will sometimes (50% of the time?) deadlock, never exiting, with no exceptions raised. Oddly, if ASYNC_WORKERS is set to 0 or 16 (i.e., only subprocesses or only event loops), it runs reliably.
I tested this in an x86_64 Ubuntu 20.04.2 VM with Python 3.8.6. I was only able to reproduce it when the VM had more than one CPU, and I was unable to reproduce it on x86_64 MacOS.
title: Deadlock when mixing event loops and subprocesses
versions: Python 3.8
Added file: https://bugs.python.org/file49967/subprocess_asyncio_deadlock.py
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