https://github.com/python/cpython/commit/329865b883c4c51026c6abe656f2c0e83fed2c4e commit: 329865b883c4c51026c6abe656f2c0e83fed2c4e branch: 3.13 author: Miss Islington (bot) <[email protected]> committer: serhiy-storchaka <[email protected]> date: 2024-11-22T17:08:18Z summary:
[3.13] gh-88110: Clear concurrent.futures.thread._threads_queues after fork to avoid joining parent process' threads (GH-126098) (GH-127163) Threads are gone after fork, so clear the queues too. Otherwise the child process (here created via multiprocessing.Process) crashes on interpreter exit. (cherry picked from commit 1848ce61f349533ae5892a8c24c2e0e3c364fc8a) Co-authored-by: Andrei Bodrov <[email protected]> Co-authored-by: Serhiy Storchaka <[email protected]> files: A Misc/NEWS.d/next/Library/2023-02-15-23-54-42.gh-issue-88110.KU6erv.rst M Lib/concurrent/futures/thread.py M Lib/test/test_concurrent_futures/test_thread_pool.py diff --git a/Lib/concurrent/futures/thread.py b/Lib/concurrent/futures/thread.py index a024033f35fb54..9021dde48ef1e4 100644 --- a/Lib/concurrent/futures/thread.py +++ b/Lib/concurrent/futures/thread.py @@ -41,6 +41,7 @@ def _python_exit(): os.register_at_fork(before=_global_shutdown_lock.acquire, after_in_child=_global_shutdown_lock._at_fork_reinit, after_in_parent=_global_shutdown_lock.release) + os.register_at_fork(after_in_child=_threads_queues.clear) class _WorkItem: diff --git a/Lib/test/test_concurrent_futures/test_thread_pool.py b/Lib/test/test_concurrent_futures/test_thread_pool.py index 2b5bea9f4055a2..4324241b374967 100644 --- a/Lib/test/test_concurrent_futures/test_thread_pool.py +++ b/Lib/test/test_concurrent_futures/test_thread_pool.py @@ -66,6 +66,25 @@ def submit(pool): with futures.ProcessPoolExecutor(1, mp_context=mp.get_context('fork')) as workers: workers.submit(tuple) + @support.requires_fork() + @unittest.skipUnless(hasattr(os, 'register_at_fork'), 'need os.register_at_fork') + def test_process_fork_from_a_threadpool(self): + # bpo-43944: clear concurrent.futures.thread._threads_queues after fork, + # otherwise child process will try to join parent thread + def fork_process_and_return_exitcode(): + # Ignore the warning about fork with threads. + with self.assertWarnsRegex(DeprecationWarning, + r"use of fork\(\) may lead to deadlocks in the child"): + p = mp.get_context('fork').Process(target=lambda: 1) + p.start() + p.join() + return p.exitcode + + with futures.ThreadPoolExecutor(1) as pool: + process_exitcode = pool.submit(fork_process_and_return_exitcode).result() + + self.assertEqual(process_exitcode, 0) + def test_executor_map_current_future_cancel(self): stop_event = threading.Event() log = [] diff --git a/Misc/NEWS.d/next/Library/2023-02-15-23-54-42.gh-issue-88110.KU6erv.rst b/Misc/NEWS.d/next/Library/2023-02-15-23-54-42.gh-issue-88110.KU6erv.rst new file mode 100644 index 00000000000000..42a83edc3ba68d --- /dev/null +++ b/Misc/NEWS.d/next/Library/2023-02-15-23-54-42.gh-issue-88110.KU6erv.rst @@ -0,0 +1,2 @@ +Fixed :class:`multiprocessing.Process` reporting a ``.exitcode`` of 1 even on success when +using the ``"fork"`` start method while using a :class:`concurrent.futures.ThreadPoolExecutor`. _______________________________________________ Python-checkins mailing list -- [email protected] To unsubscribe send an email to [email protected] https://mail.python.org/mailman3/lists/python-checkins.python.org/ Member address: [email protected]
