bpo-31783: Fix a race condition creating workers during shutdown (#13171)
* bpo-31783: Fix a race condition while creating workers during interpreter shutdown
* 📜🤖 Added by blurb_it.
diff --git a/Lib/concurrent/futures/thread.py b/Lib/concurrent/futures/thread.py
index d84b3aa..b89f8f2 100644
--- a/Lib/concurrent/futures/thread.py
+++ b/Lib/concurrent/futures/thread.py
@@ -29,10 +29,14 @@
_threads_queues = weakref.WeakKeyDictionary()
_shutdown = False
+# Lock that ensures that new workers are not created while the interpreter is
+# shutting down. Must be held while mutating _threads_queues and _shutdown.
+_global_shutdown_lock = threading.Lock()
def _python_exit():
global _shutdown
- _shutdown = True
+ with _global_shutdown_lock:
+ _shutdown = True
items = list(_threads_queues.items())
for t, q in items:
q.put(None)
@@ -156,7 +160,7 @@
self._initargs = initargs
def submit(self, fn, /, *args, **kwargs):
- with self._shutdown_lock:
+ with self._shutdown_lock, _global_shutdown_lock:
if self._broken:
raise BrokenThreadPool(self._broken)