Fix: lora kernel pre-patch applied despite post-patch not applied (#2772)

* fix: do not pre-patch self attention if lora dropout non-zero

* fix: add test to check patch not applied

* fix: test

* fix: test config check

* fix where we check so that tests don't break

* fix: test

---------

Co-authored-by: Wing Lian <wing@axolotl.ai>

src/axolotl/loaders/patch_manager.py

@@ -166,6 +166,17 @@ class PatchManager:
     def _apply_self_attention_lora_patch(self):
         """Apply self-attention LoRA patches if configured."""
         if self.cfg.lora_qkv_kernel or self.cfg.lora_o_kernel:
+            # Only patch if conditions are met
+            can_patch = (
+                self.cfg.lora_dropout == 0
+                if hasattr(self.cfg, "lora_dropout")
+                else True
+            )  # default to True if lora_dropout is not set
+
+            if not can_patch:
+                LOG.warning("Cannot patch self-attention - requires no dropout")
+                return
+
             from axolotl.monkeypatch.lora_kernels import patch_self_attn_lora
 
             patch_self_attn_lora(self.cfg)

src/axolotl/monkeypatch/lora_kernels.py

@@ -274,6 +274,29 @@ def find_mlp_in_layer(
                 )
 
 
+def get_layers(model: PeftModelForCausalLM) -> list[nn.Module]:
+    """
+    Get the layers of the model. Handles text-only and multimodal models.
+
+    Args:
+        model: A PEFT model.
+
+    Returns:
+        A list of layers.
+    """
+    pretrained_model = model.model
+
+    # check for multimodal models first
+    if hasattr(pretrained_model, "language_model"):
+        return pretrained_model.language_model.layers
+    if hasattr(pretrained_model, "model"):
+        return pretrained_model.model.layers
+
+    raise NotImplementedError(
+        f"Model type {model.config.model_type} is not supported yet. Please create an Issue."
+    )
+
+
 def apply_lora_kernel_patches(
     model: PeftModelForCausalLM, cfg: DictDefault
 ) -> PeftModelForCausalLM:
@@ -345,17 +368,7 @@ def apply_lora_kernel_patches(
     if activation not in SUPPORTED_ACTIVATIONS:
         raise NotImplementedError(f"Activation {activation} is not supported")
 
-    layers = []
-    # check for multimodal models first
-    pretrained_model = model.model
-    if hasattr(pretrained_model, "language_model"):
-        layers = pretrained_model.language_model.layers
-    elif hasattr(pretrained_model, "model"):
-        layers = pretrained_model.model.layers
-    else:
-        raise NotImplementedError(
-            f"Model type {model.config.model_type} is not supported yet. Please create an Issue."
-        )
+    layers = get_layers(model)
 
     # Patch each layer
     for layer in layers:

tests/e2e/patched/lora_kernels/test_lora_kernel_patching.py

@@ -25,7 +25,9 @@ from axolotl.loaders.model import ModelLoader
 from axolotl.loaders.tokenizer import load_tokenizer
 from axolotl.monkeypatch.lora_kernels import (
     apply_lora_kernel_patches,
+    find_self_attn_in_layer,
     get_attention_cls_from_config,
+    get_layers,
     patch_self_attn_lora,
 )
 from axolotl.utils.dict import DictDefault
@@ -501,3 +503,63 @@ def test_kernel_training_integration_auto_enable(temp_dir):
                 break
 
     assert found_patched_attn
+
+
+def test_kernel_training_integration_dropout_non_zero():
+    """Test model loading with dropout non-zero should not patch."""
+
+    from axolotl.cli.utils import load_model_and_tokenizer
+
+    # Create minimal config
+    cfg = DictDefault(
+        {
+            "base_model": "HuggingFaceTB/SmolLM2-135M",
+            "tokenizer_config": "HuggingFaceTB/SmolLM2-135M",
+            "learning_rate": 0.000001,
+            "datasets": [
+                {
+                    "path": "mhenrichsen/alpaca_2k_test",
+                    "type": "alpaca",
+                }
+            ],
+            "micro_batch_size": 1,
+            "gradient_accumulation_steps": 1,
+            "adapter": "lora",
+            "lora_r": 8,
+            "lora_alpha": 16,
+            "lora_dropout": 0.1,
+            "lora_target_linear": True,
+            "sequence_len": 1024,
+        }
+    )
+
+    # Get original attention class
+    attention_cls = get_attention_cls_from_config(cfg)
+
+    # Store original state before patching
+    original_forward_method = attention_cls.forward
+
+    # Load model
+    model, tokenizer, _ = load_model_and_tokenizer(cfg=cfg)
+
+    # We call modelloader as that's where the patches are applied
+    # despite the fact that we're not using it to load the model
+    model_loader = ModelLoader(cfg, tokenizer)
+
+    # Apply patch
+    model_loader.patch_manager._apply_self_attention_lora_patch()  # pylint: disable=protected-access
+
+    # Verify patch was not applied
+    assert attention_cls.forward == original_forward_method
+
+    # Apply apply_lora_kernel_patches
+    model_loader.patch_manager._apply_lora_kernel_patch(  # pylint: disable=protected-access
+        model
+    )
+
+    # Verify patch was not applied
+    layers = get_layers(model)
+    for layer in layers:
+        for self_attn in find_self_attn_in_layer(layer):
+            assert not hasattr(self_attn, "apply_qkv")
+            assert not hasattr(self_attn, "apply_o")