gh-144986: Fix memory leak in atexit.register() (#144987)

Author: ashm-dev

Misc/NEWS.d/next/Library/2026-02-19-00-00-00.gh-issue-144986.atexit-leak.rst

@@ -0,0 +1,2 @@
+Fix a memory leak in :func:`atexit.register`.
+Patch by Shamil Abdulaev.

Modules/atexitmodule.c

@@ -185,13 +185,17 @@ atexit_register(PyObject *module, PyObject *args, PyObject *kwargs)
         return NULL;
     }
     PyObject *func_args = PyTuple_GetSlice(args, 1, PyTuple_GET_SIZE(args));
+    if (func_args == NULL) {
+        return NULL;
+    }
     PyObject *func_kwargs = kwargs;
 
     if (func_kwargs == NULL)
     {
         func_kwargs = Py_None;
     }
     PyObject *callback = PyTuple_Pack(3, func, func_args, func_kwargs);
+    Py_DECREF(func_args);
     if (callback == NULL)
     {
         return NULL;