[Trainer/bug] Ensure model is not inference mode (CORE-72) (#13400)

* Ensure model is not inference mode

* force clone inside training mode to avoid inference tensor

* Allow force deepcopy for model patcher
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Kohaku-Blueleaf 2026-06-10 11:07:47 +08:00 committed by GitHub
parent 46d45aade1
commit f350acdf21
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2 changed files with 41 additions and 40 deletions

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@ -379,10 +379,11 @@ class ModelPatcher:
def get_clone_model_override(self):
return self.model, (self.backup, self.backup_buffers, self.object_patches_backup, self.pinned)
def clone(self, disable_dynamic=False, model_override=None):
def clone(self, disable_dynamic=False, model_override=None, force_deepcopy=False):
class_ = self.__class__
if self.is_dynamic() and disable_dynamic:
class_ = ModelPatcher
if self.is_dynamic() and disable_dynamic or force_deepcopy:
if self.is_dynamic() and disable_dynamic:
class_ = ModelPatcher
if model_override is None:
if self.cached_patcher_init is None:
raise RuntimeError("Cannot create non-dynamic delegate: cached_patcher_init is not initialized.")

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@ -1149,45 +1149,45 @@ class TrainLoraNode(io.ComfyNode):
# Process conditioning
positive = _process_conditioning(positive)
# Setup model and dtype
mp = model.clone()
use_grad_scaler = False
lora_dtype = node_helpers.string_to_torch_dtype(lora_dtype)
if training_dtype != "none":
dtype = node_helpers.string_to_torch_dtype(training_dtype)
mp.set_model_compute_dtype(dtype)
else:
# Detect model's native dtype for autocast
model_dtype = mp.model.get_dtype()
if model_dtype == torch.float16:
dtype = torch.float16
# GradScaler only supports float16 gradients, not bfloat16.
# Only enable it when lora params will also be in float16.
if lora_dtype != torch.bfloat16:
use_grad_scaler = True
# Warn about fp16 accumulation instability during training
if PerformanceFeature.Fp16Accumulation in args.fast:
logging.warning(
"WARNING: FP16 model detected with fp16_accumulation enabled. "
"This combination can be numerically unstable during training and may cause NaN values. "
"Suggested fixes: 1) Set training_dtype to 'bf16', or 2) Disable fp16_accumulation (remove from --fast flags)."
)
else:
# For fp8, bf16, or other dtypes, use bf16 autocast
dtype = torch.bfloat16
# Prepare latents and compute counts
latents_dtype = dtype if dtype not in (None,) else torch.bfloat16
latents, num_images, multi_res = _prepare_latents_and_count(
latents, latents_dtype, bucket_mode
)
# Validate and expand conditioning
positive = _validate_and_expand_conditioning(positive, num_images, bucket_mode)
with torch.inference_mode(False):
# Setup model and dtype
mp = model.clone(force_deepcopy=True)
use_grad_scaler = False
lora_dtype = node_helpers.string_to_torch_dtype(lora_dtype)
if training_dtype != "none":
dtype = node_helpers.string_to_torch_dtype(training_dtype)
mp.set_model_compute_dtype(dtype)
else:
# Detect model's native dtype for autocast
model_dtype = mp.model.get_dtype()
if model_dtype == torch.float16:
dtype = torch.float16
# GradScaler only supports float16 gradients, not bfloat16.
# Only enable it when lora params will also be in float16.
if lora_dtype != torch.bfloat16:
use_grad_scaler = True
# Warn about fp16 accumulation instability during training
if PerformanceFeature.Fp16Accumulation in args.fast:
logging.warning(
"WARNING: FP16 model detected with fp16_accumulation enabled. "
"This combination can be numerically unstable during training and may cause NaN values. "
"Suggested fixes: 1) Set training_dtype to 'bf16', or 2) Disable fp16_accumulation (remove from --fast flags)."
)
else:
# For fp8, bf16, or other dtypes, use bf16 autocast
dtype = torch.bfloat16
# Prepare latents and compute counts
latents_dtype = dtype if dtype not in (None,) else torch.bfloat16
latents, num_images, multi_res = _prepare_latents_and_count(
latents, latents_dtype, bucket_mode
)
# Validate and expand conditioning
positive = _validate_and_expand_conditioning(positive, num_images, bucket_mode)
# Setup models for training
mp.model.requires_grad_(False)
mp.model.requires_grad_(False).train()
# Load existing LoRA weights if provided
existing_weights, existing_steps = _load_existing_lora(existing_lora)