RuntimeError: UR error on ADL-N with IPEX 2.5/2.6 using .to(torch.float16)

[blue-notes-robot]

Describe the bug

Problem statement
Executing basic PyTorch operations on an Intel N150 (Alder Lake N "ADL-N") integrated GPU using the xpu device consistently fails with RuntimeError: UR error. This occurs even for fundamental operations like data type conversion (.to(torch.float16)).

Environments

• Self-compiled IPEX/PyTorch: IPEX v2.5.10+xpu / PyTorch v2.5.1 built from source using the compile_bundle.sh script against the oneAPI 2025.0.2 toolkit (from intel/oneapi-basekit:2025.0.2-0-devel-ubuntu24.04).
• Official Pre-built Docker Images: intel/intel-extension-for-pytorch:2.5.10-xpu and intel/intel-extension-for-pytorch:2.6.10-xpu.

MWE
The following minimal command reliably reproduces the error inside the affected Docker environments (both custom-built and official) when run with access to the host GPU:

SYCL_UR_TRACE=1 python -c "import torch; import intel_extension_for_pytorch; t = torch.tensor([0], device='xpu'); print(t.to(torch.float16))"

Output
Running the minimal example produces the following output, including UR loader messages and the final traceback. This output is consistent across the self-built environment and the official 2.5.10-xpu / 2.6.10-xpu Docker images.

[W401 10:47:29.656434432 OperatorEntry.cpp:155] Warning: Warning only once for all operators,  other operators may also be overridden.
  Overriding a previously registered kernel for the same operator and the same dispatch key
  operator: aten::_cummax_helper(Tensor self, Tensor(a!) values, Tensor(b!) indices, int dim) -> ()
    registered at /ipex/pytorch/build/aten/src/ATen/RegisterSchema.cpp:6
  dispatch key: XPU
  previous kernel: registered at /ipex/pytorch/build/aten/src/ATen/RegisterCPU.cpp:30476
       new kernel: registered at /ipex/intel-extension-for-pytorch/build/Release/csrc/gpu/csrc/aten/generated/ATen/RegisterXPU.cpp:2971 (function operator())
<LOADER>[INFO]: loaded adapter 0x0x61763fc88180 (libur_adapter_level_zero.so.0)
<LOADER>[INFO]: loaded adapter 0x0x61763fc89cc0 (libur_adapter_opencl.so.0)
<LOADER>[INFO]: failed to load adapter 'libur_adapter_cuda.so.0' with error: libur_adapter_cuda.so.0: cannot open shared object file: No such file or directory
<LOADER>[INFO]: failed to load adapter '/opt/intel/oneapi/compiler/2025.0/lib/libur_adapter_cuda.so.0' with error: /opt/intel/oneapi/compiler/2025.0/lib/libur_adapter_cuda.so.0: cannot open shared object file: No such file or directory
<LOADER>[INFO]: failed to load adapter 'libur_adapter_hip.so.0' with error: libur_adapter_hip.so.0: cannot open shared object file: No such file or directory
<LOADER>[INFO]: failed to load adapter '/opt/intel/oneapi/compiler/2025.0/lib/libur_adapter_hip.so.0' with error: /opt/intel/oneapi/compiler/2025.0/lib/libur_adapter_hip.so.0: cannot open shared object file: No such file or directory
<LOADER>[INFO]: failed to load adapter 'libur_adapter_native_cpu.so.0' with error: libur_adapter_native_cpu.so.0: cannot open shared object file: No such file or directory
<LOADER>[INFO]: failed to load adapter '/opt/intel/oneapi/compiler/2025.0/lib/libur_adapter_native_cpu.so.0' with error: /opt/intel/oneapi/compiler/2025.0/lib/libur_adapter_native_cpu.so.0: cannot open shared object file: No such file or directory
Traceback (most recent call last):
  File "<string>", line 1, in <module>
RuntimeError: UR error

SYCL_UR_TRACE=-1 reveals:

(.hQueue = 0x585e6230dc20, .hKernel = 0x585e6244def0, .workDim = 1, .pGlobalWorkOffset = 0x585e5f064b40 (0), .pGlobalWorkSize = 0x585e5f064b10 (224), .pLocalWorkSize = 0x585e5f064b28 (224), .numEventsInWaitList = 0, .phEventWaitList = {}, .phEvent = 0x7ffca67e6718 (0x585e6244f6a0)) -> UR_RESULT_ERROR_INVALID_ARGUMENT;`

Might be related to this issue in the pytorch repo but posting here since I compiled via IPEX and not 100% sure about the relevance.

Versions

env.txt

[ZailiWang]

Thanks for reporting this, we will take a look and get back to you.

[ZailiWang]

Hi, would you run the command with unitrace and provide the output log?
unitrace can be installed following the guidance here. Basically the steps would be

• Ensure the oneAPI basekit env variables are activated (via e.g. source /opt/intel/oneapi/setvars.sh)
• mkdir build && cd build
• cmake -DCMAKE_BUILD_TYPE=Release -DBUILD_WITH_MPI=0 ..
• make install

You may need to logon root account in case some authentication error raised like:

CMake Error at cmake_install.cmake:52 (file):
  file INSTALL cannot copy file
  "/test/unitrace/pti-gpu/tools/unitrace/build/unitrace" to
  "/usr/local/bin/unitrace": Success.

After the installation completed, try with command:

NEOReadDebugKeys=1 PrintDebugSettings=1 PrintDebugMessages=1 LogAlignedAllocations=1 LogAllocationMemoryPool=1 LogAllocationType=1 LogAllocationStdout=1 nohup unitrace python -c "import torch;  import intel_extension_for_pytorch; t = torch.tensor([0], device='xpu'); print(t.to(torch.float16))" > unitrace_out.log &

[blue-notes-robot]

Here: unitrace_out.log

[Stonepia]

Hi @blue-notes-robot , thanks for the report! I could reproduce it on my local machine. I believe it should be a bug of the driver, and because the device (Gen 12th) iGPU is too old and not in our test matrix, so there might be bugs we didn't track before.

I have submitted the internal track to the driver team. Will contact back when there is update.

[Wetitpig]

Just to supplement, this error is also reproducible on the CPU Intel Core i7-12700H (also Gen 12th). Most affected are still .to(torch.dtype) conversions.