diff --git a/Lib/test/test_threading.py b/Lib/test/test_threading.py
--- a/Lib/test/test_threading.py
+++ b/Lib/test/test_threading.py
@@ -514,6 +514,7 @@
                              stdout=subprocess.PIPE)
         rc = p.wait()
         data = p.stdout.read().decode().replace('\r', '')
+        p.stdout.close()
         self.assertEqual(rc, 0, "Unexpected error")
         self.assertEqual(data, expected_output)