Issue #1856: Avoid crashes and lockups when daemon threads run while the
interpreter is shutting down; instead, these threads are now killed when
they try to take the GIL.
diff --git a/Lib/test/test_threading.py b/Lib/test/test_threading.py
index 5f99b2e..1c946da 100644
--- a/Lib/test/test_threading.py
+++ b/Lib/test/test_threading.py
@@ -12,6 +12,7 @@
import weakref
import os
import subprocess
+from test.script_helper import assert_python_ok
from test import lock_tests
@@ -463,7 +464,6 @@
"""
self._run_and_join(script)
-
@unittest.skipUnless(hasattr(os, 'fork'), "needs os.fork()")
def test_2_join_in_forked_process(self):
# Like the test above, but from a forked interpreter
@@ -655,6 +655,49 @@
output = "end of worker thread\nend of main thread\n"
self.assertScriptHasOutput(script, output)
+ def test_6_daemon_threads(self):
+ # Check that a daemon thread cannot crash the interpreter on shutdown
+ # by manipulating internal structures that are being disposed of in
+ # the main thread.
+ script = """if True:
+ import os
+ import random
+ import sys
+ import time
+ import threading
+
+ thread_has_run = set()
+
+ def random_io():
+ '''Loop for a while sleeping random tiny amounts and doing some I/O.'''
+ blank = b'x' * 200
+ while True:
+ in_f = open(os.__file__, 'r')
+ stuff = in_f.read(200)
+ null_f = open(os.devnull, 'w')
+ null_f.write(stuff)
+ time.sleep(random.random() / 1995)
+ null_f.close()
+ in_f.close()
+ thread_has_run.add(threading.current_thread())
+
+ def main():
+ count = 0
+ for _ in range(40):
+ new_thread = threading.Thread(target=random_io)
+ new_thread.daemon = True
+ new_thread.start()
+ count += 1
+ while len(thread_has_run) < count:
+ time.sleep(0.001)
+ # Trigger process shutdown
+ sys.exit(0)
+
+ main()
+ """
+ rc, out, err = assert_python_ok('-c', script)
+ self.assertFalse(err)
+
class ThreadingExceptionTests(BaseTestCase):
# A RuntimeError should be raised if Thread.start() is called