Use C stackrefs to make use of _PyObject_GetMethodStackRef safe.

Author: markshannon

Python/bytecodes.c

@@ -2328,17 +2328,22 @@ dummy_func(
             PyObject *name = GETITEM(FRAME_CO_NAMES, oparg >> 1);
             if (oparg & 1) {
                 /* Designed to work in tandem with CALL, pushes two values. */
-                _PyStackRef method = PyStackRef_NULL;
-                int is_meth = _PyObject_GetMethodStackRef(tstate, PyStackRef_AsPyObjectBorrow(owner), name, &method);
+                _PyCStackRef method;
+                _PyThreadState_PushCStackRef(tstate, &method);
+                int is_meth = _PyObject_GetMethodStackRef(tstate, PyStackRef_AsPyObjectBorrow(owner), name, &method.ref);
                 if (is_meth) {
                     /* We can bypass temporary bound method object.
                        meth is unbound method and obj is self.
                        meth | self | arg1 | ... | argN
                      */
-                    assert(!PyStackRef_IsNull(method));  // No errors on this branch
+                    assert(!PyStackRef_IsNull(method.ref));  // No errors on this branch
                     self_or_null[0] = owner;  // Transfer ownership
                     DEAD(owner);
-                    attr = method;
+                    attr = method.ref;
+            #ifdef Py_GIL_DISABLED
+                    method_ref.ref = PyStackRef_NULL;
+                    _PyThreadState_PopCStackRef(tstate, &method_ref);
+            #endif
                 }
                 else {
                     /* meth is not an unbound method (but a regular attr, or
@@ -2347,10 +2352,14 @@ dummy_func(
                        CALL that it's not a method call.
                        meth | NULL | arg1 | ... | argN
                     */
-                    attr = method;
-                    self_or_null[0] = PyStackRef_NULL;
                     PyStackRef_CLOSE(owner);
-                    ERROR_IF(PyStackRef_IsNull(method));
+                    self_or_null[0] = PyStackRef_NULL;
+                    attr = method.ref;
+            #ifdef Py_GIL_DISABLED
+                    method_ref.ref = PyStackRef_NULL;
+                    _PyThreadState_PopCStackRef(tstate, &method_ref);
+            #endif
+                    ERROR_IF(PyStackRef_IsNull(attr));
                 }
             }
             else {