Fix possible NULL pointer dereference in _PyThread_CurrentFrames (GH-96584)

Author: kumaraditya303

Misc/NEWS.d/next/Core and Builtins/2022-09-05-15-07-25.gh-issue-96582.HEsL5s.rst

@@ -0,0 +1 @@
+Fix possible ``NULL`` pointer dereference in ``_PyThread_CurrentFrames``. Patch by Kumar Aditya.

Python/pystate.c

@@ -1413,7 +1413,12 @@ _PyThread_CurrentFrames(void)
             if (id == NULL) {
                 goto fail;
             }
-            int stat = PyDict_SetItem(result, id, (PyObject *)_PyFrame_GetFrameObject(frame));
+            PyObject *frameobj = (PyObject *)_PyFrame_GetFrameObject(frame);
+            if (frameobj == NULL) {
+                Py_DECREF(id);
+                goto fail;
+            }
+            int stat = PyDict_SetItem(result, id, frameobj);
             Py_DECREF(id);
             if (stat < 0) {
                 goto fail;