https://github.com/python/cpython/commit/aeb9b65aa26444529e4adc7d6e5b0d3dd9889ec2 commit: aeb9b65aa26444529e4adc7d6e5b0d3dd9889ec2 branch: main author: Stephen Hansen <[email protected]> committer: gpshead <[email protected]> date: 2024-12-27T14:09:01-08:00 summary:
gh-127586: multiprocessing.Pool does not properly restore blocked signals (try 2) (GH-128011) Correct pthread_sigmask in resource_tracker to restore old signals Using SIG_UNBLOCK to remove blocked "ignored signals" may accidentally cause side effects if the calling parent already had said signals blocked to begin with and did not intend to unblock them when creating a pool. Use SIG_SETMASK instead with the previous mask of blocked signals to restore the original blocked set. Co-authored-by: Peter Bierma <[email protected]> Co-authored-by: Gregory P. Smith <[email protected]> files: A Misc/NEWS.d/next/Library/2024-12-03-20-28-08.gh-issue-127586.zgotYF.rst M Lib/multiprocessing/resource_tracker.py M Lib/test/_test_multiprocessing.py diff --git a/Lib/multiprocessing/resource_tracker.py b/Lib/multiprocessing/resource_tracker.py index 20ddd9c50e3d88..90e036ae905afa 100644 --- a/Lib/multiprocessing/resource_tracker.py +++ b/Lib/multiprocessing/resource_tracker.py @@ -155,13 +155,14 @@ def ensure_running(self): # that can make the child die before it registers signal handlers # for SIGINT and SIGTERM. The mask is unregistered after spawning # the child. + prev_sigmask = None try: if _HAVE_SIGMASK: - signal.pthread_sigmask(signal.SIG_BLOCK, _IGNORED_SIGNALS) + prev_sigmask = signal.pthread_sigmask(signal.SIG_BLOCK, _IGNORED_SIGNALS) pid = util.spawnv_passfds(exe, args, fds_to_pass) finally: - if _HAVE_SIGMASK: - signal.pthread_sigmask(signal.SIG_UNBLOCK, _IGNORED_SIGNALS) + if prev_sigmask is not None: + signal.pthread_sigmask(signal.SIG_SETMASK, prev_sigmask) except: os.close(w) raise diff --git a/Lib/test/_test_multiprocessing.py b/Lib/test/_test_multiprocessing.py index 80b08b8ac66899..38a03f3391d31d 100644 --- a/Lib/test/_test_multiprocessing.py +++ b/Lib/test/_test_multiprocessing.py @@ -6045,6 +6045,27 @@ def test_resource_tracker_exit_code(self): cleanup=cleanup, ) + @unittest.skipUnless(hasattr(signal, "pthread_sigmask"), "pthread_sigmask is not available") + def test_resource_tracker_blocked_signals(self): + # + # gh-127586: Check that resource_tracker does not override blocked signals of caller. + # + from multiprocessing.resource_tracker import ResourceTracker + orig_sigmask = signal.pthread_sigmask(signal.SIG_BLOCK, set()) + signals = {signal.SIGTERM, signal.SIGINT, signal.SIGUSR1} + + try: + for sig in signals: + signal.pthread_sigmask(signal.SIG_SETMASK, {sig}) + self.assertEqual(signal.pthread_sigmask(signal.SIG_BLOCK, set()), {sig}) + tracker = ResourceTracker() + tracker.ensure_running() + self.assertEqual(signal.pthread_sigmask(signal.SIG_BLOCK, set()), {sig}) + tracker._stop() + finally: + # restore sigmask to what it was before executing test + signal.pthread_sigmask(signal.SIG_SETMASK, orig_sigmask) + class TestSimpleQueue(unittest.TestCase): @classmethod diff --git a/Misc/NEWS.d/next/Library/2024-12-03-20-28-08.gh-issue-127586.zgotYF.rst b/Misc/NEWS.d/next/Library/2024-12-03-20-28-08.gh-issue-127586.zgotYF.rst new file mode 100644 index 00000000000000..80217bd4a10503 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2024-12-03-20-28-08.gh-issue-127586.zgotYF.rst @@ -0,0 +1,3 @@ +:class:`multiprocessing.pool.Pool` now properly restores blocked signal handlers +of the parent thread when creating processes via either *spawn* or +*forkserver*. _______________________________________________ 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]
