diff --git a/Modules/_zoneinfo.c b/Modules/_zoneinfo.c
index e8b2831..a288349 100644
--- a/Modules/_zoneinfo.c
+++ b/Modules/_zoneinfo.c
@@ -278,13 +278,11 @@
 
         instance =
             PyObject_CallMethod(weak_cache, "setdefault", "OO", key, tmp);
-        ((PyZoneInfo_ZoneInfo *)instance)->source = SOURCE_CACHE;
-
         Py_DECREF(tmp);
-
         if (instance == NULL) {
             return NULL;
         }
+        ((PyZoneInfo_ZoneInfo *)instance)->source = SOURCE_CACHE;
     }
 
     update_strong_cache(type, key, instance);
@@ -1622,7 +1620,7 @@
     }
 
     *abbr = PyUnicode_FromStringAndSize(str_start, str_end - str_start);
-    if (abbr == NULL) {
+    if (*abbr == NULL) {
         return -1;
     }