bpo-44422: Fix threading.enumerate() reentrant call (GH-26727)
The threading.enumerate() function now uses a reentrant lock to
prevent a hang on reentrant call.
(cherry picked from commit 243fd01047ddce1a7eb0f99a49732d123e942c63)
Co-authored-by: Victor Stinner <vstinner@python.org>
diff --git a/Lib/threading.py b/Lib/threading.py
index 6c3d49c..766011f 100644
--- a/Lib/threading.py
+++ b/Lib/threading.py
@@ -775,8 +775,11 @@ class BrokenBarrierError(RuntimeError):
def _newname(name_template):
return name_template % _counter()
-# Active thread administration
-_active_limbo_lock = _allocate_lock()
+# Active thread administration.
+#
+# bpo-44422: Use a reentrant lock to allow reentrant calls to functions like
+# threading.enumerate().
+_active_limbo_lock = RLock()
_active = {} # maps thread id to Thread object
_limbo = {}
_dangling = WeakSet()
@@ -1564,7 +1567,7 @@ def _after_fork():
# by another (non-forked) thread. http://bugs.python.org/issue874900
global _active_limbo_lock, _main_thread
global _shutdown_locks_lock, _shutdown_locks
- _active_limbo_lock = _allocate_lock()
+ _active_limbo_lock = RLock()
# fork() only copied the current thread; clear references to others.
new_active = {}