From 16fde763e59b8ca3977af99d6b69c7f1b5b67d7a Mon Sep 17 00:00:00 2001 From: "Miss Islington (bot)" <31488909+miss-islington@users.noreply.github.com> Date: Sun, 29 Dec 2024 20:02:53 +0100 Subject: [PATCH] [3.13] gh-127586: multiprocessing.Pool does not properly restore blocked signals (try 2) (GH-128011) (#128298) 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. (cherry picked from commit aeb9b65aa26444529e4adc7d6e5b0d3dd9889ec2) Co-authored-by: Stephen Hansen Co-authored-by: Peter Bierma Co-authored-by: Gregory P. Smith --- Lib/multiprocessing/resource_tracker.py | 7 ++++--- Lib/test/_test_multiprocessing.py | 21 +++++++++++++++++++ ...-12-03-20-28-08.gh-issue-127586.zgotYF.rst | 3 +++ 3 files changed, 28 insertions(+), 3 deletions(-) create mode 100644 Misc/NEWS.d/next/Library/2024-12-03-20-28-08.gh-issue-127586.zgotYF.rst diff --git a/Lib/multiprocessing/resource_tracker.py b/Lib/multiprocessing/resource_tracker.py index 20ddd9c50e3d..90e036ae905a 100644 --- a/Lib/multiprocessing/resource_tracker.py +++ b/Lib/multiprocessing/resource_tracker.py @@ -155,13 +155,14 @@ class ResourceTracker(object): # 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 ce93d94699ce..84c8fa146709 100644 --- a/Lib/test/_test_multiprocessing.py +++ b/Lib/test/_test_multiprocessing.py @@ -5950,6 +5950,27 @@ class TestResourceTracker(unittest.TestCase): 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 000000000000..80217bd4a105 --- /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*. -- 2.47.3