fix #1742

Former-commit-id: efbb32afdcf0d6aa4ca26f54c95f76dbb84f77dc

src/llmtuner/model/loader.py

@@ -81,9 +81,16 @@ def load_model_and_tokenizer(
     if add_valuehead:
         model: "AutoModelForCausalLMWithValueHead" = AutoModelForCausalLMWithValueHead.from_pretrained(model)
         patcher.patch_valuehead_model(model)
-        vhead_params = load_valuehead_params(model_args)
+
+        if model_args.adapter_name_or_path is not None:
+            vhead_path = model_args.adapter_name_or_path[-1]
+        else:
+            vhead_path = model_args.model_name_or_path
+
+        vhead_params = load_valuehead_params(vhead_path, model_args)
         if vhead_params is not None:
             model.load_state_dict(vhead_params, strict=False)
+            logger.info("Loaded valuehead from checkpoint: {}".format(vhead_path))
 
     if not is_trainable:
         model.requires_grad_(False) # fix all model params