bltinmod is borrowed, so it shouldn't be decrefed
diff --git a/Objects/exceptions.c b/Objects/exceptions.c
index 2657185..be55294 100644
--- a/Objects/exceptions.c
+++ b/Objects/exceptions.c
@@ -2210,7 +2210,6 @@
         Py_DECREF(args_tuple);
     }
 
-    Py_DECREF(bltinmod);
 }
 
 void