this is only a borrowed ref in Brett's branch
diff --git a/Objects/exceptions.c b/Objects/exceptions.c
index be55294..49f6d30 100644
--- a/Objects/exceptions.c
+++ b/Objects/exceptions.c
@@ -2209,7 +2209,7 @@
             Py_FatalError("init of pre-allocated RuntimeError failed");
         Py_DECREF(args_tuple);
     }
-
+    Py_DECREF(bltinmod);
 }
 
 void