diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index 7871043681..4e0c663e33 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -3902,6 +3902,7 @@ PyUnicode_FSDecoder(PyObject* arg, void* addr)
     PyObject *output = NULL;
     if (arg == NULL) {
         Py_DECREF(*(PyObject**)addr);
+        *(PyObject**)addr = NULL;
         return 1;
     }