[Klaud Cold] sglang v0.5.12 DeepGemm regression on B300: CUDA_ERROR_ILLEGAL_ADDRESS in fp8_fp4_gemm_nt TMA descriptor init

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Summary

SGLang v0.5.12-cu130 regresses DeepGemm on NVIDIA B300 (Blackwell, sm_120). Every GLM-5-FP8 inference run on this image crashes during CUDA graph capture with CUDA_ERROR_ILLEGAL_ADDRESS originating in DeepGemm's TMA descriptor initialization for the shared-experts FP8 GEMM. This blocks the bump in #1421 and would likely block similar B300 sglang PRs.

Upstream report

• Filed at sglang: v0.5.12 DeepGemm regression on B300 (sm_103): CUDA_ERROR_ILLEGAL_ADDRESS in fp8_fp4_gemm_nt TMA descriptor init for shared-experts FP8 GEMM sgl-project/sglang#25551

Surfaced by

• PR Update glm5-fp8-b300-sglang and -mtp SGLang image to v0.5.12-cu130 #1421 (Update glm5-fp8-b300-sglang and -mtp SGLang image to v0.5.12-cu130).

Failing GitHub Action runs

• Run: https://github.com/SemiAnalysisAI/InferenceX/actions/runs/25984496952
• Failing jobs (identical crash on all TP ranks):
  • https://github.com/SemiAnalysisAI/InferenceX/actions/runs/25984496952/job/76379310468 (8k1k, conc-128)
  • https://github.com/SemiAnalysisAI/InferenceX/actions/runs/25984496952/job/76379310585 (1k1k, conc-128)

Reproduction

Use the glm5-fp8-b300-sglang recipe but swap the image to v0.5.12-cu130. Server flags pulled from benchmarks/single_node/glm5_fp8_b300.sh:

docker run --gpus all --shm-size=32g --rm \
  -v $HF_HUB_CACHE:/root/.cache/huggingface \
  lmsysorg/sglang:v0.5.12-cu130 \
  bash -c "
    pip install --no-deps 'transformers==5.2.0' 'huggingface-hub==1.4.1' && \
    export SGL_ENABLE_JIT_DEEPGEMM=1 && \
    python3 -m sglang.launch_server \
      --model-path=zai-org/GLM-5-FP8 \
      --host=0.0.0.0 --port=8888 --trust-remote-code \
      --tensor-parallel-size=8 \
      --data-parallel-size 1 --expert-parallel-size 1 \
      --tool-call-parser glm47 --reasoning-parser glm45 \
      --kv-cache-dtype fp8_e4m3 --quantization fp8 \
      --attention-backend nsa \
      --nsa-decode-backend trtllm --nsa-prefill-backend trtllm \
      --moe-runner-backend flashinfer_trtllm \
      --cuda-graph-max-bs 128 --max-running-requests 128 \
      --mem-fraction-static 0.85 \
      --chunked-prefill-size 32768 --max-prefill-tokens 32768 \
      --enable-flashinfer-allreduce-fusion --disable-radix-cache \
      --stream-interval 30 \
      --model-loader-extra-config '{\"enable_multithread_load\": true}'
  "

Diagnosis

• Crash site (all TP ranks, simultaneous): deep_gemm.fp8_fp4_gemm_nt → _C.fp8_fp4_gemm_nt() → /deepgemm/csrc/apis/../jit_kernels/impls/runtime_utils.hpp:143 → CUDA_ERROR_ILLEGAL_ADDRESS (error 700)
• Call path: cuda_graph_runner.capture() → deepseek_v2.forward() → MoE layer forward_normal_dual_stream → _forward_shared_experts → shared_experts.gate_up_proj → fp8_kernel.deep_gemm_fp8_fp8_bf16_nt → deep_gemm_wrapper.gemm_nt_f8f8bf16 → deep_gemm.fp8_gemm_nt → native fp8_fp4_gemm_nt → CUDA_ERROR_ILLEGAL_ADDRESS in TMA descriptor runtime utils
• Working baseline: lmsysorg/sglang:v0.5.11-cu130 runs cleanly on the same recipe / hardware.

The bundled DeepGemm in v0.5.12-cu130 has a regression in its TMA-descriptor init path on Blackwell. runtime_utils.hpp:143 is the TMA descriptor validation/creation site.

Workarounds (pick one to unblock #1421)

1. Pin sglang to lmsysorg/sglang:v0.5.11-cu130 until upstream DeepGemm/Blackwell TMA fix lands.
2. Bypass DeepGemm: pass --fp8-gemm-runner-backend cutlass to the SGLang server launch — uses CUTLASS FP8 path instead of DeepGemm.
3. Disable CUDA graphs: --disable-cuda-graph — large perf hit, only useful as a smoke test.

Suggested actions

• File upstream → v0.5.12 DeepGemm regression on B300 (sm_103): CUDA_ERROR_ILLEGAL_ADDRESS in fp8_fp4_gemm_nt TMA descriptor init for shared-experts FP8 GEMM sgl-project/sglang#25551
• Pin Update glm5-fp8-b300-sglang and -mtp SGLang image to v0.5.12-cu130 #1421 to v0.5.11-cu130 OR add --fp8-gemm-runner-backend cutlass to benchmarks/single_node/glm5_fp8_b300.sh so the PR can land.
• Watch for the same regression on other B300 SGLang recipes touching DeepGemm shared-experts FP8 GEMM (e.g. [Handoff to @Oseltamivir Claude /loop] Update glm5-fp4-b300-sglang and -mtp SGLang image to v0.5.12-cu130 #1420 has a related but distinct trtllm GEMM regression at bs=128+MTP).

🤖 Filed by Claude Code

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Filed upstream: sgl-project/sglang#25551