Simon Jagoe added the comment: In the script attached to the original issue, the weakref callback that causes the hang is the callback defined in ThreadPoolExecutor._adjust_thread_count
Attached is a faulthandler stack captured from Python 3.6.1. The script submitted here uses a patched queue.get() method to force garbage collection to reliably trigger the issue, but this deadlock was observed in a real application using threadpool executors. ---------- Added file: https://bugs.python.org/file47132/executor-hang-faulthandler.txt _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue21009> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com