Issue #9448: Fix a leak of OS resources (mutexes or semaphores) when

re-initializing a buffered IO object by calling its `__init__` method.

Misc/NEWS

@@ -29,6 +29,9 @@ Extensions
 Library
 -------
 
+- Issue #9448: Fix a leak of OS resources (mutexes or semaphores) when
+  re-initializing a buffered IO object by calling its ``__init__`` method.
+
 - Issue #1713: Fix os.path.ismount(), which returned true for symbolic links
   across devices.
 

Modules/_io/bufferedio.c

@@ -636,6 +636,8 @@ _buffered_init(buffered *self)
         return -1;
     }
 #ifdef WITH_THREAD
+    if (self->lock)
+        PyThread_free_lock(self->lock);
     self->lock = PyThread_allocate_lock();
     if (self->lock == NULL) {
         PyErr_SetString(PyExc_RuntimeError, "can't allocate read lock");