Issue #11915: threading.RLock()._release_save() raises a RuntimeError if the
lock was not acquired.
diff --git a/Modules/_threadmodule.c b/Modules/_threadmodule.c
index 914d671..1aee77b 100644
--- a/Modules/_threadmodule.c
+++ b/Modules/_threadmodule.c
@@ -414,6 +414,12 @@
long owner;
unsigned long count;
+ if (self->rlock_count == 0) {
+ PyErr_SetString(PyExc_RuntimeError,
+ "cannot release un-acquired lock");
+ return NULL;
+ }
+
owner = self->rlock_owner;
count = self->rlock_count;
self->rlock_count = 0;