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[Other] error detected in the compilation of Strata/src/qwen35/q36_engine.cu

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@yudhanjaya is already working on this.

Since Oct 20, 2026.

  • #3374 by @yudhanjaya — open

Assessment

Difficulty
2/5
Estimated time
1-3 hours
Newbie friendliness
69/100
Issue type
Bug
Clarity
Clearly specified
Activity status
Active
Tech stack
cpp
Domain
backend, build-system

Research direction

Start with Strata/src/qwen35/q36_engine.cu at the reported verify_q8 error on line 1659 and inspect how that function uses __half_as_ushort. Reproduce with ./setup --setup and the Qwen3.8-Flash-Next option; done means the CUDA object compiles and setup proceeds past the reported failure.

Written by the indexing model from the issue text.

Description

needs-format

Problem:

  • After pull request on Oct-19: 22:00:00 - the compilation is failing when it is trying to Build the CUDA object CMakeFiles/strata_qwen35.dir/src/qwen35/q36_engine.cu.o

  • I started with "./setup --setup" and choose the original model "Qwen3.8-Flash-Next GSQ-RCO quants by ISTA-DASLab - the original model", and after some seconds it show an error:

/path/to/repo/Strata/src/qwen35/q36_engine.cu(1659): error: calling a __device__ function("__half_as_ushort(    ::__half)") from a __host__ function("verify_q8") is not allowed

1 error detected in the compilation of "/path/to/repo/Strata/src/qwen35/q36_engine.cu".
ninja: build stopped: subcommand failed.

 [X]  command failed (exit 2): cmake

Setup stopped. Fix the item above and run it again - everything already done is kept and skipped.
  • The thing is that the model worked before the pull request. I went back to commit 4c968e61999d237caed3139e6a714d0de52afe82 with description : gdn chunk / Volta recurrence: name the kernels in every device pass (wmma body ..... and I could run the model

Environment:

  • Ubuntu 24.04,
  • GPU RTX 2000 Ada Generation Laptop GPU, 8 GB,
  • 64 RAM,
  • i7 13th

Reproduce:

  • run ./setup --setup
  • choose : 1) Qwen3.8-Flash-Next

FAIL

Expected:

  • Go through the setup process as usual and run the model

Evidence: -- log Extended

/path/to/repo/Strata/src/prefill/moe_fused_iq.cu(1331): warning #177-D: function "strata::prefill::fused::<unnamed>::f16_d" was declared but never referenced

[5/21] Building CUDA object CMakeFiles/strata_qwen35.dir/src/qwen35/q36_engine.cu.o
FAILED: [code=2] CMakeFiles/strata_qwen35.dir/src/qwen35/q36_engine.cu.o 
/usr/bin/nvcc -forward-unknown-to-host-compiler -DSTRATA_NATIVE_EXPERTS=1 -DSTRATA_PREFILL_FUSED=1 -DSTRATA_PREFILL_MMQ=1 -DSTRATA_Q36_CPU_POOL=1 -DSTRATA_Q6K_EXPERTS=1 -DSTRATA_VERSION=\"0.1.45.3\" -I/path/to/repo/Strata/include -I/path/to/repo/Strata/third_party/llama.cpp/ggml/src/../include -O3 -DNDEBUG -std=c++20 "--generate-code=arch=compute_89,code=[compute_89,sm_89]" -MD -MT CMakeFiles/strata_qwen35.dir/src/qwen35/q36_engine.cu.o -MF CMakeFiles/strata_qwen35.dir/src/qwen35/q36_engine.cu.o.d -x cu -c /path/to/repo/Strata/src/qwen35/q36_engine.cu -o CMakeFiles/strata_qwen35.dir/src/qwen35/q36_engine.cu.o
/path/to/repo/Strata/include/strata/core/family_layout.hpp(100): warning #811-D: const variable "c" requires an initializer -- class "strata::core::ModelGeometry" has no user-provided default constructor

Remark: The warnings can be suppressed with "-diag-suppress <warning-number>"

/path/to/repo/Strata/src/qwen35/q36_engine.cu(1659): error: calling a __device__ function("__half_as_ushort(    ::__half)") from a __host__ function("verify_q8") is not allowed

1 error detected in the compilation of "/path/to/repo/Strata/src/qwen35/q36_engine.cu".
[18/21] Building CUDA object CMakeFiles/strata_mmq.dir/ggml-tq-overlay/template-instances/mmq-instance-tqk6.cu.o
ninja: build stopped: subcommand failed.
  (the build stopped - trying it once more)
  > /usr/bin/cmake --build /path/to/repo/Strata/build --target strata -j 14
[2/4] Building CUDA object CMakeFiles/strata_qwen35.dir/src/qwen35/q36_engine.cu.o
FAILED: [code=2] CMakeFiles/strata_qwen35.dir/src/qwen35/q36_engine.cu.o 
/usr/bin/nvcc -forward-unknown-to-host-compiler -DSTRATA_NATIVE_EXPERTS=1 -DSTRATA_PREFILL_FUSED=1 -DSTRATA_PREFILL_MMQ=1 -DSTRATA_Q36_CPU_POOL=1 -DSTRATA_Q6K_EXPERTS=1 -DSTRATA_VERSION=\"0.1.45.3\" -I/path/to/repo/Strata/include -I/path/to/repo/Strata/third_party/llama.cpp/ggml/src/../include -O3 -DNDEBUG -std=c++20 "--generate-code=arch=compute_89,code=[compute_89,sm_89]" -MD -MT CMakeFiles/strata_qwen35.dir/src/qwen35/q36_engine.cu.o -MF CMakeFiles/strata_qwen35.dir/src/qwen35/q36_engine.cu.o.d -x cu -c /path/to/repo/Strata/src/qwen35/q36_engine.cu -o CMakeFiles/strata_qwen35.dir/src/qwen35/q36_engine.cu.o
/path/to/repo/Strata/include/strata/core/family_layout.hpp(100): warning #811-D: const variable "c" requires an initializer -- class "strata::core::ModelGeometry" has no user-provided default constructor

Remark: The warnings can be suppressed with "-diag-suppress <warning-number>"

/path/to/repo/Strata/src/qwen35/q36_engine.cu(1659): error: calling a __device__ function("__half_as_ushort(    ::__half)") from a __host__ function("verify_q8") is not allowed

1 error detected in the compilation of "/path/to/repo/Strata/src/qwen35/q36_engine.cu".
ninja: build stopped: subcommand failed.

  [X]  command failed (exit 2): cmake

Setup stopped. Fix the item above and run it again - everything already done is kept and skipped.

Thank you in advance

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