[3.12] gh-110656: Fix logging test_post_fork_child_no_deadlock() if ASAN (GH-110657) (#110664)

gh-110656: Fix logging test_post_fork_child_no_deadlock() if ASAN (GH-110657)

Skip test_post_fork_child_no_deadlock() if Python is built with ASAN.

Add support.HAVE_ASAN_FORK_BUG.
(cherry picked from commit f901f56313)

Co-authored-by: Victor Stinner <vstinner@python.org>

Lib/test/_test_multiprocessing.py

@@ -78,10 +78,10 @@ except ImportError:
     msvcrt = None
 
 
-if support.check_sanitizer(address=True):
+if support.HAVE_ASAN_FORK_BUG:
     # gh-89363: Skip multiprocessing tests if Python is built with ASAN to
     # work around a libasan race condition: dead lock in pthread_create().
-    raise unittest.SkipTest("libasan has a pthread_create() dead lock")
+    raise unittest.SkipTest("libasan has a pthread_create() dead lock related to thread+fork")
 
 
 def latin(s):

Lib/test/support/__init__.py

@@ -428,6 +428,10 @@ def skip_if_sanitizer(reason=None, *, address=False, memory=False, ub=False):
     skip = check_sanitizer(address=address, memory=memory, ub=ub)
     return unittest.skipIf(skip, reason)
 
+# gh-89363: True if fork() can hang if Python is built with Address Sanitizer
+# (ASAN): libasan race condition, dead lock in pthread_create().
+HAVE_ASAN_FORK_BUG = check_sanitizer(address=True)
+
 
 def system_must_validate_cert(f):
     """Skip the test on TLS certificate validation failures."""

Lib/test/test_logging.py

@@ -76,6 +76,13 @@ except ImportError:
     pass
 
 
+# gh-89363: Skip fork() test if Python is built with Address Sanitizer (ASAN)
+# to work around a libasan race condition, dead lock in pthread_create().
+skip_if_asan_fork = unittest.skipIf(
+    support.HAVE_ASAN_FORK_BUG,
+    "libasan has a pthread_create() dead lock related to thread+fork")
+
+
 class BaseTest(unittest.TestCase):
 
     """Base class for logging tests."""
@@ -730,6 +737,7 @@ class HandlerTest(BaseTest):
     # register_at_fork mechanism is also present and used.
     @support.requires_fork()
     @threading_helper.requires_working_threading()
+    @skip_if_asan_fork
     def test_post_fork_child_no_deadlock(self):
         """Ensure child logging locks are not held; bpo-6721 & bpo-36533."""
         class _OurHandler(logging.Handler):

Lib/test/test_threading.py

@@ -35,19 +35,12 @@ threading_helper.requires_working_threading(module=True)
 platforms_to_skip = ('netbsd5', 'hp-ux11')
 
 
-# gh-89363: Skip fork() test if Python is built with Address Sanitizer (ASAN)
-# to work around a libasan race condition, dead lock in pthread_create().
-skip_if_asan_fork = support.skip_if_sanitizer(
-                        "libasan has a pthread_create() dead lock",
-                        address=True)
-
-
 def skip_unless_reliable_fork(test):
     if not support.has_fork_support:
         return unittest.skip("requires working os.fork()")(test)
     if sys.platform in platforms_to_skip:
         return unittest.skip("due to known OS bug related to thread+fork")(test)
-    if support.check_sanitizer(address=True):
+    if support.HAVE_ASAN_FORK_BUG:
         return unittest.skip("libasan has a pthread_create() dead lock related to thread+fork")(test)
     return test