Original file line numberDiff line numberDiff line change@@ -0,0 +1,2 @@
1+:class:`collections.deque` prevent rare crash when calling ``extend`` under
2+high memory pressure conditions.
Original file line numberDiff line numberDiff line change@@ -512,7 +512,6 @@ deque_extend_impl(dequeobject *deque, PyObject *iterable)
512512iternext=*Py_TYPE(it)->tp_iternext;
513513while ((item=iternext(it)) !=NULL) {
514514if (deque_append_lock_held(deque, item, maxlen) ==-1) {
515-Py_DECREF(item);
516515Py_DECREF(it);
517516returnNULL;
518517 }