Fix dynamo stack trace by yushangdi · Pull Request #165930 · pytorch/pytorch

yushangdi · 2025-10-20T20:38:46Z

Add message to Attribute error so we see Developer debug context: raised exception AttributeError(["'Linear' object has no attribute 'w'"]) instead of just Developer debug context: raised exception AttributeError([])
Add stack trace in ObservedException so we display the inner most error stack trace back to user code

Output:

/data/users/shangdiy/pytorch/torch/__init__.py:2641: UserWarning: You are calling torch.compile inside torch.export region. To capture an useful graph, we will implicitly switch to torch.compile(backend=eager)
  warnings.warn(
Traceback (most recent call last):
  File "/data/users/shangdiy/pytorch/torch/_dynamo/variables/user_defined.py", line 1385, in var_getattr
    subobj = self._getattr_static(name)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/data/users/shangdiy/pytorch/torch/_dynamo/variables/user_defined.py", line 1256, in _getattr_static
    subobj = type(self.value).__getattribute__(self.value, name)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'Linear' object has no attribute 'w'

During handling of the above exception, another exception occurred:

torch._dynamo.exc.ObservedAttributeError: 'Linear' object has no attribute 'w'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/data/users/shangdiy/pytorch/test.py", line 34, in <module>
    mod = torch._dynamo.functional_export._dynamo_graph_capture_for_export(Model())(x)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/data/users/shangdiy/pytorch/torch/_dynamo/functional_export.py", line 481, in inner
    out = fullgraph_capture(
          ^^^^^^^^^^^^^^^^^^
  File "/data/users/shangdiy/pytorch/torch/_dynamo/convert_frame.py", line 1053, in fullgraph_capture
    return _fullgraph_capture_frame(
           ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/data/users/shangdiy/pytorch/torch/_dynamo/convert_frame.py", line 1115, in _fullgraph_capture_frame
    raise e.with_traceback(None) from e.__cause__  # User compiler error
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
torch._dynamo.exc.Unsupported: Observed exception
  Explanation: Dynamo found no exception handler at the top-level compiled function when encountering an exception. Exception will propagate outside the compiled region.
  Hint: Dynamo has detected that tracing the code will result in an error when running in eager. Please double check that your code doesn't contain a similar error when actually running eager/uncompiled.
  Hint: It may be possible to write Dynamo tracing rules for this code. Please report an issue to PyTorch if you encounter this graph break often and it is causing performance issues.

  Developer debug context: raised exception AttributeError(["'Linear' object has no attribute 'w'"])

 For more details about this graph break, please visit: https://meta-pytorch.github.io/compile-graph-break-site/gb/gb0088.html

from user code:
   File "/data/users/shangdiy/pytorch/torch/_dynamo/functional_export.py", line 171, in forward
    res = self._export_root(*args, **kwargs)
  File "/data/users/shangdiy/pytorch/test.py", line 31, in forward
    weight = self.linear.w

Set TORCHDYNAMO_VERBOSE=1 for the internal stack trace (please do this especially if you're reporting a bug to PyTorch). For even more developer context, set TORCH_LOGS="+dynamo"

cc @voznesenskym @penguinwu @EikanWang @jgong5 @Guobing-Chen @XiaobingSuper @zhuhaozhe @blzheng @wenzhe-nrv @jiayisunx @chenyang78 @kadeng @chauhang @amjames @Lucaskabela @mlazos

pytorch-bot · 2025-10-20T20:38:50Z

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Lucaskabela

Flagged a few more places we might be able to bubble up the exception here

torch/_dynamo/variables/nn_module.py

torch/_dynamo/variables/user_defined.py

yushangdi · 2025-10-21T00:19:18Z

@pytorchbot merge

pytorchmergebot · 2025-10-21T00:21:22Z

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Fixes pytorch#165911 - Add message to Attribute error so we see ` Developer debug context: raised exception AttributeError(["'Linear' object has no attribute 'w'"])` instead of just `Developer debug context: raised exception AttributeError([])` - Add stack trace in `ObservedException` so we display the inner most error stack trace back to user code Output: ``` /data/users/shangdiy/pytorch/torch/__init__.py:2641: UserWarning: You are calling torch.compile inside torch.export region. To capture an useful graph, we will implicitly switch to torch.compile(backend=eager) warnings.warn( Traceback (most recent call last): File "/data/users/shangdiy/pytorch/torch/_dynamo/variables/user_defined.py", line 1385, in var_getattr subobj = self._getattr_static(name) ^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/data/users/shangdiy/pytorch/torch/_dynamo/variables/user_defined.py", line 1256, in _getattr_static subobj = type(self.value).__getattribute__(self.value, name) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ AttributeError: 'Linear' object has no attribute 'w' During handling of the above exception, another exception occurred: torch._dynamo.exc.ObservedAttributeError: 'Linear' object has no attribute 'w' The above exception was the direct cause of the following exception: Traceback (most recent call last): File "/data/users/shangdiy/pytorch/test.py", line 34, in <module> mod = torch._dynamo.functional_export._dynamo_graph_capture_for_export(Model())(x) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/data/users/shangdiy/pytorch/torch/_dynamo/functional_export.py", line 481, in inner out = fullgraph_capture( ^^^^^^^^^^^^^^^^^^ File "/data/users/shangdiy/pytorch/torch/_dynamo/convert_frame.py", line 1053, in fullgraph_capture return _fullgraph_capture_frame( ^^^^^^^^^^^^^^^^^^^^^^^^^ File "/data/users/shangdiy/pytorch/torch/_dynamo/convert_frame.py", line 1115, in _fullgraph_capture_frame raise e.with_traceback(None) from e.__cause__ # User compiler error ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ torch._dynamo.exc.Unsupported: Observed exception Explanation: Dynamo found no exception handler at the top-level compiled function when encountering an exception. Exception will propagate outside the compiled region. Hint: Dynamo has detected that tracing the code will result in an error when running in eager. Please double check that your code doesn't contain a similar error when actually running eager/uncompiled. Hint: It may be possible to write Dynamo tracing rules for this code. Please report an issue to PyTorch if you encounter this graph break often and it is causing performance issues. Developer debug context: raised exception AttributeError(["'Linear' object has no attribute 'w'"]) For more details about this graph break, please visit: https://meta-pytorch.github.io/compile-graph-break-site/gb/gb0088.html from user code: File "/data/users/shangdiy/pytorch/torch/_dynamo/functional_export.py", line 171, in forward res = self._export_root(*args, **kwargs) File "/data/users/shangdiy/pytorch/test.py", line 31, in forward weight = self.linear.w Set TORCHDYNAMO_VERBOSE=1 for the internal stack trace (please do this especially if you're reporting a bug to PyTorch). For even more developer context, set TORCH_LOGS="+dynamo" ``` Pull Request resolved: pytorch#165930 Approved by: https://github.com/anijain2305

pytorch-bot bot added ciflow/inductor module: dynamo labels Oct 20, 2025

yushangdi mentioned this pull request Oct 20, 2025

Incorrect user code stack when using torch._dynamo.functional_export._dynamo_graph_capture_for_export #165911

Closed

yushangdi force-pushed the dynamo_stack_trace branch from 0b6c213 to ba17d42 Compare October 20, 2025 20:49

yushangdi added the release notes: dynamo label Oct 20, 2025

yushangdi requested review from anijain2305, ezyang and williamwen42 October 20, 2025 20:49

anijain2305 approved these changes Oct 20, 2025

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Lucaskabela reviewed Oct 20, 2025

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fix dynamo stack trace

e192036

yushangdi force-pushed the dynamo_stack_trace branch from ba17d42 to e192036 Compare October 20, 2025 20:56

yushangdi added the ciflow/trunk Trigger trunk jobs on your pull request label Oct 20, 2025

pytorchmergebot added the merging label Oct 21, 2025

pytorchmergebot closed this in 4a6cf0a Oct 21, 2025

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Fix dynamo stack trace#165930

Fix dynamo stack trace#165930
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