fix: gemma3 loss in forward pass (#2473) [skip ci]

* fix: gemma3 loss in forward pass

* fix: lint

* fix: move patch before plugins

* Update src/axolotl/monkeypatch/gemma3.py

Co-authored-by: salman <salman.mohammadi@outlook.com>

---------

Co-authored-by: Wing Lian <wing.lian@gmail.com>
Co-authored-by: salman <salman.mohammadi@outlook.com>
This commit is contained in:
NanoCode012
2025-04-02 20:34:41 +07:00
committed by GitHub
parent 45bf634d17
commit 7abc71dc0b
2 changed files with 247 additions and 0 deletions

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@@ -0,0 +1,238 @@
"""Monkeypatch for gemma3 conditional generation forward to fix loss exploding"""
# pylint: disable=duplicate-code
from typing import Optional, Tuple, Union
import torch
from transformers.cache_utils import Cache
from transformers.models.gemma3.modeling_gemma3 import (
_CONFIG_FOR_DOC,
GEMMA3_INPUTS_DOCSTRING,
Gemma3CausalLMOutputWithPast,
logger,
)
from transformers.utils import (
add_start_docstrings_to_model_forward,
is_torchdynamo_compiling,
replace_return_docstrings,
)
from transformers.utils.deprecation import deprecate_kwarg
@deprecate_kwarg("num_logits_to_keep", version="4.50", new_name="logits_to_keep")
@add_start_docstrings_to_model_forward(GEMMA3_INPUTS_DOCSTRING)
@replace_return_docstrings(
output_type=Gemma3CausalLMOutputWithPast, config_class=_CONFIG_FOR_DOC
)
def new_forward(
self,
input_ids: torch.LongTensor = None,
pixel_values: torch.FloatTensor = None,
attention_mask: Optional[torch.Tensor] = None,
position_ids: Optional[torch.LongTensor] = None,
past_key_values: Optional[Union[list[torch.FloatTensor], Cache]] = None,
token_type_ids: Optional[torch.LongTensor] = None,
cache_position: Optional[torch.LongTensor] = None,
inputs_embeds: Optional[torch.FloatTensor] = None,
labels: Optional[torch.LongTensor] = None,
use_cache: Optional[bool] = None,
output_attentions: Optional[bool] = None,
output_hidden_states: Optional[bool] = None,
return_dict: Optional[bool] = None,
logits_to_keep: Union[int, torch.Tensor] = 0,
**lm_kwargs,
) -> Union[Tuple, Gemma3CausalLMOutputWithPast]:
r"""
labels (`torch.LongTensor` of shape `(batch_size, sequence_length)`, *optional*):
Labels for computing the masked language modeling loss. Indices should either be in `[0, ...,
config.text_config.vocab_size]` or -100 (see `input_ids` docstring). Tokens with indices set to `-100` are ignored
(masked), the loss is only computed for the tokens with labels in `[0, ..., config.text_config.vocab_size]`.
logits_to_keep (`int` or `torch.Tensor`, *optional*):
If an `int`, compute logits for the last `logits_to_keep` tokens. If `0`, calculate logits for all
`input_ids` (special case). Only last token logits are needed for generation, and calculating them only for that
token can save memory, which becomes pretty significant for long sequences or large vocabulary size.
If a `torch.Tensor`, must be 1D corresponding to the indices to keep in the sequence length dimension.
This is useful when using packed tensor format (single dimension for batch and sequence length).
Returns:
Example:
```python
>>> from PIL import Image
>>> import requests
>>> from transformers import AutoProcessor, Gemma3ForConditionalGeneration
>>> model = Gemma3ForConditionalGeneration.from_pretrained("google/Gemma3-test-224px-hf")
>>> processor = AutoProcessor.from_pretrained("google/Gemma3-test-224px-hf")
>>> prompt = "answer en Where is the cow standing?"
>>> url = "https://huggingface.co/gv-hf/Gemma3-test-224px-hf/resolve/main/cow_beach_1.png"
>>> image = Image.open(requests.get(url, stream=True).raw)
>>> inputs = processor(images=image, text=prompt, return_tensors="pt")
>>> # Generate
>>> generate_ids = model.generate(**inputs, max_length=30)
>>> processor.batch_decode(generate_ids, skip_special_tokens=True, clean_up_tokenization_spaces=False)[0]
"answer en Where is the cow standing?\nbeach"
```"""
if (input_ids is None) ^ (inputs_embeds is not None):
raise ValueError("You must specify exactly one of input_ids or inputs_embeds")
output_attentions = (
output_attentions
if output_attentions is not None
else self.config.output_attentions
)
output_hidden_states = (
output_hidden_states
if output_hidden_states is not None
else self.config.output_hidden_states
)
return_dict = (
return_dict if return_dict is not None else self.config.use_return_dict
)
is_training = token_type_ids is not None and labels is not None
# Replace image id with PAD if the image token is OOV, to avoid index-errors
if input_ids is not None and self.config.image_token_index >= self.vocab_size:
special_image_mask = input_ids == self.config.image_token_index
llm_input_ids = input_ids.clone()
llm_input_ids[special_image_mask] = 0
else:
llm_input_ids = input_ids
if inputs_embeds is None:
inputs_embeds = self.get_input_embeddings()(llm_input_ids)
if cache_position is None:
past_seen_tokens = (
past_key_values.get_seq_length() if past_key_values is not None else 0
)
cache_position = torch.arange(
past_seen_tokens,
past_seen_tokens + inputs_embeds.shape[1],
device=inputs_embeds.device,
)
# Merge text and images
if pixel_values is not None:
image_features = self.get_image_features(pixel_values)
if input_ids is None:
special_image_mask = inputs_embeds == self.get_input_embeddings()(
torch.tensor(
self.config.image_token_index,
dtype=torch.long,
device=inputs_embeds.device,
)
)
else:
special_image_mask = (input_ids == self.config.image_token_index).unsqueeze(
-1
)
special_image_mask = special_image_mask.expand_as(inputs_embeds).to(
inputs_embeds.device
)
if (
not is_torchdynamo_compiling()
and inputs_embeds[special_image_mask].numel() != image_features.numel()
):
image_tokens_in_text = (special_image_mask).sum(dim=1).sum(dim=0)[0]
raise ValueError(
f"Number of images does not match number of special image tokens in the input text. "
f"Got {image_tokens_in_text} image tokens in the text but {image_features.shape[0] * image_features.shape[1]} "
"tokens from image embeddings."
)
image_features = image_features.to(inputs_embeds.device, inputs_embeds.dtype)
inputs_embeds = inputs_embeds.masked_scatter(special_image_mask, image_features)
# mask out pad-token-ids in labels for BC
if labels is not None and self.pad_token_id in labels:
logger.warning_once(
"`labels` contains `pad_token_id` which will be masked with `config.ignore_index`. "
"You have to mask out `pad_token_id` when preparing `labels`, this behavior will be removed in v.4.46.",
)
labels = torch.where(
input_ids == self.pad_token_id, self.config.ignore_index, labels
)
causal_mask = self._update_causal_mask( # pylint: disable=protected-access
attention_mask,
token_type_ids,
past_key_values,
cache_position,
inputs_embeds,
is_training,
)
outputs = self.language_model(
attention_mask=causal_mask,
position_ids=position_ids,
past_key_values=past_key_values,
inputs_embeds=inputs_embeds,
use_cache=use_cache,
output_attentions=output_attentions,
output_hidden_states=output_hidden_states,
return_dict=return_dict,
cache_position=cache_position,
logits_to_keep=logits_to_keep,
**lm_kwargs,
)
logits = outputs[0]
loss = None
if labels is not None:
if attention_mask is not None:
# Get the shifted attention mask
shift_attention_mask = attention_mask[:, -logits.shape[1] + 1 :].to(
logits.device
) # +1 for shift
# Filter logits and labels based on attention mask
valid_indices = shift_attention_mask != 0
filtered_logits = logits[..., :-1, :][valid_indices]
filtered_labels = labels[..., 1:][valid_indices.to(labels.device)]
# TODO: do we need to handle num_items_in_batch given we filter the logits and labels?
loss = self.loss_function(
logits=filtered_logits,
labels=None, # we pass shift_labels
shift_labels=filtered_labels,
vocab_size=self.config.text_config.vocab_size,
**lm_kwargs,
)
else:
# Standard case without filtering
loss = self.loss_function(
logits=logits,
labels=labels,
vocab_size=self.config.text_config.vocab_size,
**lm_kwargs,
)
if not return_dict:
output = (logits,) + outputs[1:]
return (loss,) + output if loss is not None else output
return Gemma3CausalLMOutputWithPast(
loss=loss,
logits=logits,
past_key_values=outputs.past_key_values,
hidden_states=outputs.hidden_states,
attentions=outputs.attentions,
image_hidden_states=image_features if pixel_values is not None else None,
)
def patch_gemma3conditionalgeneration_forward():
from transformers.models.gemma3.modeling_gemma3 import (
Gemma3ForConditionalGeneration,
)
Gemma3ForConditionalGeneration.forward = new_forward

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@@ -535,6 +535,15 @@ class ModelLoader:
self.auto_model_loader = AutoModelForCausalLM # pylint: disable=invalid-name
def apply_patches(self) -> None:
# patch gemma3 conditional generation forward before loading plugins
# as it could be overridden by plugins
if self.cfg.model_config_type == "gemma3":
from axolotl.monkeypatch.gemma3 import (
patch_gemma3conditionalgeneration_forward,
)
patch_gemma3conditionalgeneration_forward()
# load any patches from plugins
from axolotl.integrations.base import PluginManager