[issue33997] multiprocessing Pool hangs in terminate()
New submission from Erik Wolf : The terminate() method of multiprocessing.Pool hangs sporadically. I could track this issue down to the fact that _handle_results() hangs in the outqueue-cleanup. poll() returned True but get() actually hangs endlessly never returning any data. -- components: Windows messages: 320713 nosy: Erik Wolf, paul.moore, steve.dower, tim.golden, zach.ware priority: normal severity: normal status: open title: multiprocessing Pool hangs in terminate() type: behavior versions: Python 3.6, Python 3.7 ___ Python tracker <https://bugs.python.org/issue33997> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue33997] multiprocessing Pool hangs in terminate()
Erik Wolf added the comment: To help get an idea of the racing condition I created a trace with several additional debug outputs in pool.py and connection.py "=== Creating new pool ===" marks a new start of a pool using the Pool.imap() function. The iteration is terminated at some time and a new pool is created with a new call to imap(). The last log entry shows the location of the last call which currently hangs endlessly. I am not a multithreading/winapi expert so I could not fix the actual issue with _winapi.WaitForMultipleObjects but the fix in the PR actually ignores preceding issues when polling more data than actually needed for the two sentinels. Remark: I have also seen this issue in linux with the same application but was not able to debug it so far. -- Added file: https://bugs.python.org/file47659/debug.trace ___ Python tracker <https://bugs.python.org/issue33997> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
