Skip to content

Fix fp16 LoRA unscale crash after validation in train_dreambooth_lora.py #13895

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
sayakpaul merged 2 commits into from
Jun 9, 2026
Merged

Fix fp16 LoRA unscale crash after validation in train_dreambooth_lora.py #13895

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
4a9c51a
Fix fp16 LoRA unscale crash after validation in train_dreambooth_lora.py
HaozheZhang6 Jun 9, 2026
1de289a
Merge branch 'main' into fix-dreambooth-lora-fp16-validation-unscale
sayakpaul Jun 9, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
6 changes: 5 additions & 1 deletion examples/dreambooth/train_dreambooth_lora.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -147,7 +147,11 @@ def log_validation(

pipeline.scheduler = DPMSolverMultistepScheduler.from_config(pipeline.scheduler.config, **scheduler_args)

pipeline = pipeline.to(accelerator.device, dtype=torch_dtype)
# Don't pass `dtype` here: under fp16 the trainable LoRA params are kept in fp32 (see
# `cast_training_params` above) and the validation pipeline shares the training `unet`, so casting it
# to fp16 would break the next optimizer step ("Attempting to unscale FP16 gradients"). Matches the
# SDXL script.
pipeline = pipeline.to(accelerator.device)
pipeline.set_progress_bar_config(disable=True)

# run inference
Expand Down
Loading