From: Sam Gross <colesbury@gmail.com>
Date: Fri, 20 Oct 2023 16:51:34 +0000 (+0200)
Subject: gh-111119: Fix flaky test test_lock_two_threads (gh-111124)
X-Git-Tag: v3.13.0a2~387
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=264f4af506bf5b587105eab37fcfb7dfa62d6587;p=thirdparty%2FPython%2Fcpython.git

gh-111119: Fix flaky test test_lock_two_threads (gh-111124)
---

diff --git a/Modules/_testinternalcapi/test_lock.c b/Modules/_testinternalcapi/test_lock.c
index 33b49dacaa94..82a0c827deed 100644
--- a/Modules/_testinternalcapi/test_lock.c
+++ b/Modules/_testinternalcapi/test_lock.c
@@ -75,10 +75,18 @@ test_lock_two_threads(PyObject *self, PyObject *obj)
     assert(test_data.m.v == 1);
 
     PyThread_start_new_thread(lock_thread, &test_data);
-    while (!_Py_atomic_load_int(&test_data.started)) {
-        pysleep(10);
-    }
-    pysleep(10);  // allow some time for the other thread to try to lock
+
+    // wait up to two seconds for the lock_thread to attempt to lock "m"
+    int iters = 0;
+    uint8_t v;
+    do {
+        pysleep(10);  // allow some time for the other thread to try to lock
+        v = _Py_atomic_load_uint8_relaxed(&test_data.m.v);
+        assert(v == 1 || v == 3);
+        iters++;
+    } while (v != 3 && iters < 200);
+
+    // both the "locked" and the "has parked" bits should be set
     assert(test_data.m.v == 3);
 
     PyMutex_Unlock(&test_data.m);