use atomic store in PyObject_GenericSetDict

Author: kumaraditya303

Objects/object.c

@@ -1931,7 +1931,9 @@ PyObject_GenericSetDict(PyObject *obj, PyObject *value, void *context)
         return -1;
     }
     Py_BEGIN_CRITICAL_SECTION(obj);
-    Py_XSETREF(*dictptr, Py_NewRef(value));
+    PyObject *olddict = *dictptr;
+    FT_ATOMIC_STORE_PTR_RELEASE(*dictptr, Py_NewRef(value));
+    Py_XDECREF(olddict);
     Py_END_CRITICAL_SECTION();
     return 0;
 }