vllm - 💡(How to fix) Fix [Bug]: The Qwen 3.5 model cannot disable thinking in version 0.18.0. [1 participants]

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vllm-project/vllm#37794Fetched 2026-04-08 01:12:55
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Fix / Workaround

============================== CPU Info

架构: x86_64 CPU 运行模式: 32-bit, 64-bit Address sizes: 46 bits physical, 57 bits virtual 字节序: Little Endian CPU: 24 在线 CPU 列表: 0-23 厂商 ID: GenuineIntel 型号名称: Intel(R) Xeon(R) Silver 4310 CPU @ 2.10GHz CPU 系列: 6 型号: 106 每个核的线程数: 2 每个座的核数: 12 座: 1 步进: 6 CPU 最大 MHz: 3300.0000 CPU 最小 MHz: 800.0000 BogoMIPS: 4200.00 标记: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc art arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc cpuid aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 sdbg fma cx16 xtpr pdcm pcid dca sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm 3dnowprefetch cpuid_fault epb cat_l3 ssbd mba ibrs ibpb stibp ibrs_enhanced tpr_shadow flexpriority ept vpid ept_ad fsgsbase tsc_adjust bmi1 avx2 smep bmi2 erms invpcid cqm rdt_a avx512f avx512dq rdseed adx smap avx512ifma clflushopt clwb intel_pt avx512cd sha_ni avx512bw avx512vl xsaveopt xsavec xgetbv1 xsaves cqm_llc cqm_occup_llc cqm_mbm_total cqm_mbm_local split_lock_detect wbnoinvd dtherm ida arat pln pts vnmi avx512vbmi umip pku ospke avx512_vbmi2 gfni vaes vpclmulqdq avx512_vnni avx512_bitalg tme avx512_vpopcntdq la57 rdpid fsrm md_clear pconfig flush_l1d arch_capabilities 虚拟化: VT-x L1d 缓存: 576 KiB (12 instances) L1i 缓存: 384 KiB (12 instances) L2 缓存: 15 MiB (12 instances) L3 缓存: 18 MiB (1 instance) NUMA 节点: 1 NUMA 节点0 CPU: 0-23 Vulnerability Gather data sampling: Mitigation; Microcode Vulnerability Indirect target selection: Vulnerable Vulnerability Itlb multihit: Not affected Vulnerability L1tf: Not affected Vulnerability Mds: Not affected Vulnerability Meltdown: Not affected Vulnerability Mmio stale data: Mitigation; Clear CPU buffers; SMT vulnerable Vulnerability Reg file data sampling: Not affected Vulnerability Retbleed: Not affected Vulnerability Spec rstack overflow: Not affected Vulnerability Spec store bypass: Mitigation; Speculative Store Bypass disabled via prctl Vulnerability Spectre v1: Mitigation; usercopy/swapgs barriers and __user pointer sanitization Vulnerability Spectre v2: Mitigation; Enhanced / Automatic IBRS; IBPB conditional; PBRSB-eIBRS SW sequence; BHI SW loop, KVM SW loop Vulnerability Srbds: Not affected Vulnerability Tsa: Not affected Vulnerability Tsx async abort: Not affected Vulnerability Vmscape: Not affected

RAW_BUFFERClick to expand / collapse

Your current environment

(vllm) cheng@cheng:~$ python collect_env.py Collecting environment information...

    System Info

============================== OS : Ubuntu 22.04.5 LTS (x86_64) GCC version : (Ubuntu 11.4.0-1ubuntu1~22.04.3) 11.4.0 Clang version : Could not collect CMake version : version 3.22.1 Libc version : glibc-2.35

============================== PyTorch Info

PyTorch version : 2.10.0+cu128 Is debug build : False CUDA used to build PyTorch : 12.8 ROCM used to build PyTorch : N/A

============================== Python Environment

Python version : 3.12.13 | packaged by Anaconda, Inc. | (main, Mar 19 2026, 20:20:58) [GCC 14.3.0] (64-bit runtime) Python platform : Linux-6.8.0-106-generic-x86_64-with-glibc2.35

============================== CUDA / GPU Info

Is CUDA available : True CUDA runtime version : 12.8.93 CUDA_MODULE_LOADING set to : GPU models and configuration : GPU 0: NVIDIA GeForce RTX 3090 GPU 1: NVIDIA GeForce RTX 3090 GPU 2: NVIDIA GeForce RTX 3090 GPU 3: NVIDIA GeForce RTX 3090

Nvidia driver version : 590.48.01 cuDNN version : Could not collect HIP runtime version : N/A MIOpen runtime version : N/A Is XNNPACK available : True

============================== CPU Info

架构: x86_64 CPU 运行模式: 32-bit, 64-bit Address sizes: 46 bits physical, 57 bits virtual 字节序: Little Endian CPU: 24 在线 CPU 列表: 0-23 厂商 ID: GenuineIntel 型号名称: Intel(R) Xeon(R) Silver 4310 CPU @ 2.10GHz CPU 系列: 6 型号: 106 每个核的线程数: 2 每个座的核数: 12 座: 1 步进: 6 CPU 最大 MHz: 3300.0000 CPU 最小 MHz: 800.0000 BogoMIPS: 4200.00 标记: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc art arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc cpuid aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 sdbg fma cx16 xtpr pdcm pcid dca sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm 3dnowprefetch cpuid_fault epb cat_l3 ssbd mba ibrs ibpb stibp ibrs_enhanced tpr_shadow flexpriority ept vpid ept_ad fsgsbase tsc_adjust bmi1 avx2 smep bmi2 erms invpcid cqm rdt_a avx512f avx512dq rdseed adx smap avx512ifma clflushopt clwb intel_pt avx512cd sha_ni avx512bw avx512vl xsaveopt xsavec xgetbv1 xsaves cqm_llc cqm_occup_llc cqm_mbm_total cqm_mbm_local split_lock_detect wbnoinvd dtherm ida arat pln pts vnmi avx512vbmi umip pku ospke avx512_vbmi2 gfni vaes vpclmulqdq avx512_vnni avx512_bitalg tme avx512_vpopcntdq la57 rdpid fsrm md_clear pconfig flush_l1d arch_capabilities 虚拟化: VT-x L1d 缓存: 576 KiB (12 instances) L1i 缓存: 384 KiB (12 instances) L2 缓存: 15 MiB (12 instances) L3 缓存: 18 MiB (1 instance) NUMA 节点: 1 NUMA 节点0 CPU: 0-23 Vulnerability Gather data sampling: Mitigation; Microcode Vulnerability Indirect target selection: Vulnerable Vulnerability Itlb multihit: Not affected Vulnerability L1tf: Not affected Vulnerability Mds: Not affected Vulnerability Meltdown: Not affected Vulnerability Mmio stale data: Mitigation; Clear CPU buffers; SMT vulnerable Vulnerability Reg file data sampling: Not affected Vulnerability Retbleed: Not affected Vulnerability Spec rstack overflow: Not affected Vulnerability Spec store bypass: Mitigation; Speculative Store Bypass disabled via prctl Vulnerability Spectre v1: Mitigation; usercopy/swapgs barriers and __user pointer sanitization Vulnerability Spectre v2: Mitigation; Enhanced / Automatic IBRS; IBPB conditional; PBRSB-eIBRS SW sequence; BHI SW loop, KVM SW loop Vulnerability Srbds: Not affected Vulnerability Tsa: Not affected Vulnerability Tsx async abort: Not affected Vulnerability Vmscape: Not affected

============================== Versions of relevant libraries

[pip3] flashinfer-python==0.6.6 [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==9.10.2.21 [pip3] nvidia-cudnn-frontend==1.18.0 [pip3] nvidia-cufft-cu12==11.3.3.83 [pip3] nvidia-cufile-cu12==1.13.1.3 [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-cutlass-dsl==4.4.2 [pip3] nvidia-cutlass-dsl-libs-base==4.4.2 [pip3] nvidia-ml-py==13.595.45 [pip3] nvidia-nccl-cu12==2.27.5 [pip3] nvidia-nvjitlink-cu12==12.8.93 [pip3] nvidia-nvshmem-cu12==3.4.5 [pip3] nvidia-nvtx-cu12==12.8.90 [pip3] pyzmq==27.1.0 [pip3] torch==2.10.0 [pip3] torch_c_dlpack_ext==0.1.5 [pip3] torchaudio==2.10.0 [pip3] torchvision==0.25.0 [pip3] transformers==4.57.6 [pip3] triton==3.6.0 [conda] flashinfer-python 0.6.6 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 9.10.2.21 pypi_0 pypi [conda] nvidia-cudnn-frontend 1.18.0 pypi_0 pypi [conda] nvidia-cufft-cu12 11.3.3.83 pypi_0 pypi [conda] nvidia-cufile-cu12 1.13.1.3 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-cutlass-dsl 4.4.2 pypi_0 pypi [conda] nvidia-cutlass-dsl-libs-base 4.4.2 pypi_0 pypi [conda] nvidia-ml-py 13.595.45 pypi_0 pypi [conda] nvidia-nccl-cu12 2.27.5 pypi_0 pypi [conda] nvidia-nvjitlink-cu12 12.8.93 pypi_0 pypi [conda] nvidia-nvshmem-cu12 3.4.5 pypi_0 pypi [conda] nvidia-nvtx-cu12 12.8.90 pypi_0 pypi [conda] pyzmq 27.1.0 pypi_0 pypi [conda] torch 2.10.0 pypi_0 pypi [conda] torch-c-dlpack-ext 0.1.5 pypi_0 pypi [conda] torchaudio 2.10.0 pypi_0 pypi [conda] torchvision 0.25.0 pypi_0 pypi [conda] transformers 4.57.6 pypi_0 pypi [conda] triton 3.6.0 pypi_0 pypi

============================== vLLM Info

ROCM Version : Could not collect vLLM Version : 0.18.0 vLLM Build Flags: CUDA Archs: Not Set; ROCm: Disabled GPU Topology: GPU0 GPU1 GPU2 GPU3 CPU Affinity NUMA Affinity GPU NUMA ID GPU0 X NODE NODE NODE 0-23 0 N/A GPU1 NODE X NODE NODE 0-23 0 N/A GPU2 NODE NODE X NODE 0-23 0 N/A GPU3 NODE NODE NODE X 0-23 0 N/A

Legend:

X = Self SYS = Connection traversing PCIe as well as the SMP interconnect between NUMA nodes (e.g., QPI/UPI) NODE = Connection traversing PCIe as well as the interconnect between PCIe Host Bridges within a NUMA node PHB = Connection traversing PCIe as well as a PCIe Host Bridge (typically the CPU) PXB = Connection traversing multiple PCIe bridges (without traversing the PCIe Host Bridge) PIX = Connection traversing at most a single PCIe bridge NV# = Connection traversing a bonded set of # NVLinks

============================== Environment Variables

LD_LIBRARY_PATH=/usr/local/cuda-12.8/lib64 PYTORCH_NVML_BASED_CUDA_CHECK=1 TORCHINDUCTOR_COMPILE_THREADS=1 TORCHINDUCTOR_CACHE_DIR=/tmp/torchinductor_cheng

🐛 Describe the bug

CUDA_VISIBLE_DEVICES=0,1,2,3 PYTHONIOENCODING=utf-8 vllm serve /home/cheng/model/Qwen3.5-27B-AWQ
--host 0.0.0.0
--port 8000
--api-key abc123
--served-model-name Qwen3.5-27B
--override-generation-config '{"temperature": 1, "top_p": 0.95, "top_k": 40}'
--trust-remote-code
--tensor-parallel-size 4
--enable-prefix-caching
--enable-chunked-prefill
--max-model-len 131072
--gpu-memory-utilization 0.85
--kv-cache-dtype fp8
--enable-auto-tool-choice
--tool-call-parser qwen3_coder
--reasoning-parser qwen3
--max-num-seqs 10
--attention-config.backend FLASHINFER
--speculative-config '{"method": "mtp", "num_speculative_tokens": 2}' --default-chat-template-kwargs '{"enable_thinking": false}'

Thinking cannot be disabled when upgrading to version 0.18.0

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Fix Plan

To fix the issue of thinking not being disabled when upgrading to version 0.18.0, follow these steps:

  • Update the default-chat-template-kwargs to include the correct syntax for disabling thinking.
  • Verify that the enable_thinking parameter is set to false in the default-chat-template-kwargs dictionary.

Example code:

--default-chat-template-kwargs '{"enable_thinking": false, "disable_thinking": true}'

Alternatively, you can try updating the speculative-config to disable thinking:

--speculative-config '{"method": "mtp", "num_speculative_tokens": 2, "enable_thinking": false}'

Verification

To verify that the fix worked, run the vllm serve command with the updated parameters and check that thinking is disabled.

Extra Tips

  • Make sure to update the default-chat-template-kwargs and speculative-config parameters correctly to avoid any syntax errors.
  • If you are still experiencing issues, try checking the documentation for any updates or changes to the parameters.
  • You can also try resetting the default-chat-template-kwargs and speculative-config parameters to their default values and then updating them again to see if that resolves the issue.

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