[QNN] AttributeError in `_mark_nodes_as_annotated` when a layer_norm node has optional weight as None

[KevinUW114514]

🐛 Describe the bug

[QNN] AttributeError in _mark_nodes_as_annotated when a layer_norm node has optional weight as None

Bug Description

During PT2E quantization via prepare_pt2e in the Qualcomm QNN backend, an AttributeError is raised in _mark_nodes_as_annotated when annotating aten.layer_norm.default nodes whose optional weight argument is None.

Error Traceback

AttributeError: 'NoneType' object has no attribute 'meta'
  File "executorch/backends/qualcomm/quantizer/rules.py", line 32, in _mark_nodes_as_annotated
    if Q_ANNOTATION_KEY not in node.meta:

Environment

• ExecuTorch version: 1.3.0a0+490ec5c
• Backend: Qualcomm QNN (HTP)
• Quantization: PT2E w8a8

Labels

• bug
• module:qualcomm

Versions

$ python collect_env.py
Collecting environment information...
PyTorch version: 2.11.0+cu128
Is debug build: False
CUDA used to build PyTorch: 12.8
ROCM used to build PyTorch: N/A

OS: Ubuntu 22.04.4 LTS (x86_64)
GCC version: (Ubuntu 11.4.0-1ubuntu1~22.04.3) 11.4.0
Clang version: 14.0.0-1ubuntu1.1
CMake version: version 3.31.10
Libc version: glibc-2.35

Python version: 3.10.20 | packaged by conda-forge | (main, Mar 5 2026, 16:42:22) [GCC 14.3.0] (64-bit runtime)
Python platform: Linux-5.15.0-173-generic-x86_64-with-glibc2.35

CPU:
Architecture: x86_64

Versions of relevant libraries:
[pip3] executorch==1.3.0a0+490ec5c
[pip3] numpy==2.2.6
[pip3] nvidia-cublas-cu12==12.8.4.1
[pip3] nvidia-cuda-cupti-cu12==12.8.90
[pip3] nvidia-cuda-nvrtc-cu12==12.8.93
[pip3] nvidia-cuda-runtime-cu12==12.8.90
[pip3] nvidia-cudnn-cu12==9.19.0.56
[pip3] nvidia-cufft-cu12==11.3.3.83
[pip3] nvidia-curand-cu12==10.3.9.90
[pip3] nvidia-cusolver-cu12==11.7.3.90
[pip3] nvidia-cusparse-cu12==12.5.8.93
[pip3] nvidia-cusparselt-cu12==0.7.1
[pip3] nvidia-nccl-cu12==2.28.9
[pip3] nvidia-nvjitlink-cu12==12.8.93
[pip3] nvidia-nvtx-cu12==12.8.90
[pip3] pytorch_tokenizers==1.1.0
[pip3] torch==2.11.0+cu128
[pip3] torchao==0.17.0+git02105d46c
[pip3] torchaudio==2.11.0+cu128
[pip3] torchdata==0.11.0
[pip3] torchsr==1.0.4
[pip3] torchtune==0.0.0
[pip3] torchvision==0.26.0+cu128
[pip3] triton==3.6.0+git884fdae8
[conda] executorch 1.3.0a0+490ec5c pypi_0 pypi
[conda] numpy 2.2.6 pypi_0 pypi
[conda] nvidia-cublas-cu12 12.8.4.1 pypi_0 pypi
[conda] nvidia-cuda-cupti-cu12 12.8.90 pypi_0 pypi
[conda] nvidia-cuda-nvrtc-cu12 12.8.93 pypi_0 pypi
[conda] nvidia-cuda-runtime-cu12 12.8.90 pypi_0 pypi
[conda] nvidia-cudnn-cu12 9.19.0.56 pypi_0 pypi
[conda] nvidia-cufft-cu12 11.3.3.83 pypi_0 pypi
[conda] nvidia-curand-cu12 10.3.9.90 pypi_0 pypi
[conda] nvidia-cusolver-cu12 11.7.3.90 pypi_0 pypi
[conda] nvidia-cusparse-cu12 12.5.8.93 pypi_0 pypi
[conda] nvidia-cusparselt-cu12 0.7.1 pypi_0 pypi
[conda] nvidia-nccl-cu12 2.28.9 pypi_0 pypi
[conda] nvidia-nvjitlink-cu12 12.8.93 pypi_0 pypi
[conda] nvidia-nvtx-cu12 12.8.90 pypi_0 pypi
[conda] pytorch-tokenizers 1.1.0 pypi_0 pypi
[conda] torch 2.11.0+cu128 pypi_0 pypi
[conda] torchao 0.17.0+git02105d46c pypi_0 pypi
[conda] torchaudio 2.11.0+cu128 pypi_0 pypi
[conda] torchdata 0.11.0 pypi_0 pypi
[conda] torchsr 1.0.4 pypi_0 pypi
[conda] torchtune 0.0.0 pypi_0 pypi
[conda] torchvision 0.26.0+cu128 pypi_0 pypi
[conda] triton 3.6.0+git884fdae8 pypi_0 pypi

cc @cccclai @cbilgin @abhinaykukkadapu

[KevinUW114514]

The fix is pretty trivial. I am about to submit a PR for the fix

[liuyuzhe530]

看了一下问题，给出以下排查建议：

1. 检查官方文档和changelog
2. 确认依赖版本兼容性
3. 提供完整的错误日志

需要付费协助请联系我：
📧 liuyuzhe530@gmail.com
🌐 https://github.com/liuyuzhe530

[liuyuzhe530]

看了一下问题，给出以下排查建议：

1. 检查官方文档和changelog
2. 确认依赖版本兼容性
3. 提供完整的错误日志

需要付费协助请联系我：
📧 liuyuzhe530@gmail.com
🌐 https://github.com/liuyuzhe530