From: Sam Gross <colesbury@gmail.com>
Date: Wed, 18 Jun 2025 18:24:05 +0000 (-0400)
Subject: gh-135641: Fix flaky `test_capi.test_lock_two_threads` test case (gh-135642)
X-Git-Tag: v3.15.0a1~1258
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=17ac3933c3c860e08f7963cf270116a39a063be7;p=thirdparty%2FPython%2Fcpython.git

gh-135641: Fix flaky `test_capi.test_lock_two_threads` test case (gh-135642)

The mutex may have the `_Py_HAS_PARKED` bit set.
---

diff --git a/Modules/_testinternalcapi/test_lock.c b/Modules/_testinternalcapi/test_lock.c
index 8d678412fe71..8d8cb992b0e0 100644
--- a/Modules/_testinternalcapi/test_lock.c
+++ b/Modules/_testinternalcapi/test_lock.c
@@ -57,7 +57,10 @@ lock_thread(void *arg)
     _Py_atomic_store_int(&test_data->started, 1);
 
     PyMutex_Lock(m);
-    assert(m->_bits == 1);
+    // gh-135641: in rare cases the lock may still have `_Py_HAS_PARKED` set
+    // (m->_bits == 3) due to bucket collisions in the parking lot hash table
+    // between this mutex and the `test_data.done` event.
+    assert(m->_bits == 1 || m->_bits == 3);
 
     PyMutex_Unlock(m);
     assert(m->_bits == 0);