prevent double free in cleanup code (#17968)

diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index 3e5e58045fdcd0fd5f22c27742d4cfc945389281..a351caeddc7771ddee58689c388a2b8e4b4bbf09 100644 (file)
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -10627,6 +10627,7 @@ posix_listxattr(PyObject *self, PyObject *args, PyObject *kwargs)
         if (length < 0) {
             if (errno == ERANGE) {
                 PyMem_FREE(buffer);
+                buffer = NULL;
                 continue;
             }
             path_error("listxattr", &path);