diff --git a/src/python/m5/params.py b/src/python/m5/params.py
index 6c3c47e95a..f9412d70ea 100644
--- a/src/python/m5/params.py
+++ b/src/python/m5/params.py
@@ -1716,6 +1716,10 @@ class NullSimObject(object):
     def clear_parent(self, old_parent):
         pass
 
+    def descendants(self):
+        return
+        yield None
+
     def __str__(self):
         return 'Null'