From 0bdd97d42617fff876a47e27d7ed198817c0231e Mon Sep 17 00:00:00 2001 From: Steve Stagg Date: Fri, 3 Jul 2026 18:43:24 +0100 Subject: [PATCH] gh-152951 - Fix double DECREF when `newblock` fails during deque.extend calls (GH-152961) (cherry picked from commit a90576d72c8a409f7c3ffcaefafb13945e3405ab) Co-authored-by: Steve Stagg --- .../next/Library/2026-07-03-14-54-33.gh-issue-152951.u8tPCI.rst | 2 ++ Modules/_collectionsmodule.c | 1 - 2 files changed, 2 insertions(+), 1 deletion(-) create mode 100644 Misc/NEWS.d/next/Library/2026-07-03-14-54-33.gh-issue-152951.u8tPCI.rst diff --git a/Misc/NEWS.d/next/Library/2026-07-03-14-54-33.gh-issue-152951.u8tPCI.rst b/Misc/NEWS.d/next/Library/2026-07-03-14-54-33.gh-issue-152951.u8tPCI.rst new file mode 100644 index 00000000000000..c3d56c6d59c91b --- /dev/null +++ b/Misc/NEWS.d/next/Library/2026-07-03-14-54-33.gh-issue-152951.u8tPCI.rst @@ -0,0 +1,2 @@ +:class:`collections.deque` prevent rare crash when calling ``extend`` under +high memory pressure conditions. diff --git a/Modules/_collectionsmodule.c b/Modules/_collectionsmodule.c index eed976bad79283..e48fe39dda6a09 100644 --- a/Modules/_collectionsmodule.c +++ b/Modules/_collectionsmodule.c @@ -508,7 +508,6 @@ deque_extend_impl(dequeobject *deque, PyObject *iterable) iternext = *Py_TYPE(it)->tp_iternext; while ((item = iternext(it)) != NULL) { if (deque_append_lock_held(deque, item, maxlen) == -1) { - Py_DECREF(item); Py_DECREF(it); return NULL; }