gh-123828: Fix data race in _interpchannels._waiting_release (GH-124107)

Author: Zheaoli

Lib/test/test__interpchannels.py

@@ -6,7 +6,7 @@
 import time
 import unittest
 
-from test.support import import_helper, skip_if_sanitizer
+from test.support import import_helper
 
 _channels = import_helper.import_module('_interpchannels')
 from concurrent.interpreters import _crossinterp
@@ -365,7 +365,6 @@ def test_shareable(self):
         #self.assertIsNot(got, obj)
 
 
-@skip_if_sanitizer('gh-129824: race on _waiting_release', thread=True)
 class ChannelTests(TestBase):
 
     def test_create_cid(self):

Modules/_interpchannelsmodule.c

@@ -511,12 +511,12 @@ _waiting_release(_waiting_t *waiting, int received)
     assert(!waiting->received);
 
     waiting->status = WAITING_RELEASING;
-    PyThread_release_lock(waiting->mutex);
     if (waiting->received != received) {
         assert(received == 1);
         waiting->received = received;
     }
     waiting->status = WAITING_RELEASED;
+    PyThread_release_lock(waiting->mutex);
 }
 
 static void