diff options
| -rw-r--r-- | Misc/NEWS.d/next/Core and Builtins/2024-05-07-16-57-56.gh-issue-118561.wNMKVd.rst | 2 | ||||
| -rw-r--r-- | Objects/listobject.c | 3 |
2 files changed, 4 insertions, 1 deletions
diff --git a/Misc/NEWS.d/next/Core and Builtins/2024-05-07-16-57-56.gh-issue-118561.wNMKVd.rst b/Misc/NEWS.d/next/Core and Builtins/2024-05-07-16-57-56.gh-issue-118561.wNMKVd.rst new file mode 100644 index 0000000..9eaf0abb --- /dev/null +++ b/Misc/NEWS.d/next/Core and Builtins/2024-05-07-16-57-56.gh-issue-118561.wNMKVd.rst @@ -0,0 +1,2 @@ +Fix race condition in free-threaded build where :meth:`list.extend` could expose +uninitialied memory to concurrent readers. diff --git a/Objects/listobject.c b/Objects/listobject.c index 3c4e2d2..7070165 100644 --- a/Objects/listobject.c +++ b/Objects/listobject.c @@ -192,6 +192,7 @@ list_preallocate_exact(PyListObject *self, Py_ssize_t size) return -1; } items = array->ob_item; + memset(items, 0, size * sizeof(PyObject *)); #else items = PyMem_New(PyObject*, size); if (items == NULL) { @@ -199,7 +200,7 @@ list_preallocate_exact(PyListObject *self, Py_ssize_t size) return -1; } #endif - self->ob_item = items; + FT_ATOMIC_STORE_PTR_RELEASE(self->ob_item, items); self->allocated = size; return 0; } |