[WIP] bpo-40068: test_reinit_tls_after_fork() detects crashes

Lib/test/test_threading.py

@@ -897,14 +897,18 @@ def test_reinit_tls_after_fork(self):
         # Issue #13817: fork() would deadlock in a multithreaded program with
         # the ad-hoc TLS implementation.
 
+        all_status = []
+
         def do_fork_and_wait():
             # just fork a child process and wait it
             pid = os.fork()
-            if pid > 0:
-                os.waitpid(pid, 0)
-            else:
+            if not pid:
+                # child process: just exit
                 os._exit(0)
 
+            pid, status = os.waitpid(pid, 0)
+            all_status.append(status)
+
         # start a bunch of threads that will fork() child processes
         threads = []
         for i in range(16):
@@ -915,6 +919,10 @@ def do_fork_and_wait():
         for t in threads:
             t.join()
 
+        # ensure that all child processes completed successfully (no crash)
+        for status in all_status:
+            self.assertEqual(status, 0)
+
     @unittest.skipUnless(hasattr(os, 'fork'), "needs os.fork()")
     def test_clear_threads_states_after_fork(self):
         # Issue #17094: check that threads states are cleared after fork()

Misc/NEWS.d/next/Tests/2020-03-27-20-23-31.bpo-40068.HucS3F.rst

@@ -0,0 +1,2 @@
+test_reinit_tls_after_fork() of test_threading now checks if a child process
+crashed in os.fork().