diff --git a/src/transformers/configuration_utils.py b/src/transformers/configuration_utils.py
index 8d8784be39117b..a25ac51cf20bfa 100755
--- a/src/transformers/configuration_utils.py
+++ b/src/transformers/configuration_utils.py
@@ -1036,6 +1036,7 @@ def _get_non_default_generation_parameters(self) -> Dict[str, Any]:
             if decoder_config is not self:
                 default_config = decoder_config.__class__()
             else:
+                default_config = None
                 decoder_config = None
 
         # If it is a composite model, we want to check the subconfig that will be used for generation