fix: proprerly return causal model

src/axolotl/integrations/lolcats/linear_llama/modeling_linear_llama.py

@@ -79,6 +79,9 @@ class LinearLlamaForCausalLM(LlamaForCausalLM):
     Linear LLaMA model for causal language modeling.
     """
 
+    config_class = LinearLlamaConfig
+    base_model_prefix = "linear_llama"
+
     def __init__(self, config):
         super().__init__(config)
         self.model = LinearLlamaModel(config)
@@ -102,20 +105,29 @@ class LinearLlamaForCausalLM(LlamaForCausalLM):
 
         # Handle LlamaForCausalLM
         if isinstance(model, LlamaForCausalLM):
-            model = model.model
+            llama_model = model.model
+        else:
+            llama_model = model
 
         if config is None:
             raise ValueError("Missing config")
 
         from axolotl.integrations.lolcats.linearize_attention import convert_attention
 
-        new_model = convert_attention(
-            model,
+        llama_model = convert_attention(
+            llama_model,
             DictDefault(**config.attention_config),
             train_attention=train_attention,
             remove_base_attn=remove_base_attn,
         )
 
+        # initialize the model with prior weights
+        new_model = cls(config=config)
+        del new_model.model  # remove the default model
+        del new_model.lm_head  # remove the default lm_head
+        new_model.model = llama_model
+        new_model.lm_head = model.lm_head
+
         return new_model
 
     def toggle_attention(self, train: bool = True):