vllm - 💡(How to fix) Fix [Bug]: EngineCore deadlock when serving Kimi-K2.5 on 8 * H800

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Error Message

The request itself does not throw an error, and the service does not produce any error messages. I once tried waiting for over a day, and still no error messages appeared.

Fix Action

Fix / Workaround

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

Architecture: x86_64 CPU op-mode(s): 32-bit, 64-bit Address sizes: 52 bits physical, 57 bits virtual Byte Order: Little Endian CPU(s): 192 On-line CPU(s) list: 0-191 Vendor ID: GenuineIntel Model name: Intel(R) Xeon(R) Platinum 8469C CPU family: 6 Model: 143 Thread(s) per core: 2 Core(s) per socket: 48 Socket(s): 2 Stepping: 8 CPU(s) scaling MHz: 23% CPU max MHz: 3800.0000 CPU min MHz: 800.0000 BogoMIPS: 5200.00 Flags: 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 tsc_known_freq 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 cat_l2 cdp_l3 invpcid_single intel_ppin cdp_l2 ssbd mba ibrs ibpb stibp ibrs_enhanced tpr_shadow vnmi 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 avx_vnni avx512_bf16 wbnoinvd dtherm ida arat pln pts hwp hwp_notify hwp_act_window hwp_epp hwp_pkg_req hfi avx512vbmi umip pku ospke waitpkg avx512_vbmi2 gfni vaes vpclmulqdq avx512_vnni avx512_bitalg tme avx512_vpopcntdq rdpid bus_lock_detect cldemote movdiri movdir64b enqcmd fsrm md_clear serialize tsxldtrk pconfig arch_lbr amx_bf16 avx512_fp16 amx_tile amx_int8 flush_l1d arch_capabilities Virtualization: VT-x L1d cache: 4.5 MiB (96 instances) L1i cache: 3 MiB (96 instances) L2 cache: 192 MiB (96 instances) L3 cache: 195 MiB (2 instances) NUMA node(s): 2 NUMA node0 CPU(s): 0-47,96-143 NUMA node1 CPU(s): 48-95,144-191 Vulnerability Gather data sampling: Not affected Vulnerability Itlb multihit: Not affected Vulnerability L1tf: Not affected Vulnerability Mds: Not affected Vulnerability Meltdown: Not affected Vulnerability Mmio stale data: Not affected Vulnerability Retbleed: Not affected Vulnerability Spec rstack overflow: Not affected Vulnerability Spec store bypass: Mitigation; Speculative Store Bypass disabled via prctl and seccomp Vulnerability Spectre v1: Mitigation; usercopy/swapgs barriers and __user pointer sanitization Vulnerability Spectre v2: Mitigation; Enhanced IBRS, IBPB conditional, RSB filling, PBRSB-eIBRS SW sequence Vulnerability Srbds: Not affected Vulnerability Tsx async abort: Not affected

Code Example

Collecting environment information...
==============================
        System Info
==============================
OS                           : Debian GNU/Linux 12 (bookworm) (x86_64)
GCC version                  : (Debian 12.2.0-14+deb12u1) 12.2.0
Clang version                : Could not collect
CMake version                : version 3.31.6
Libc version                 : glibc-2.36

==============================
       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
XPU used to build PyTorch    : N/A

==============================
      Python Environment
==============================
Python version               : 3.11.2 (main, Apr 28 2025, 14:11:48) [GCC 12.2.0] (64-bit runtime)
Python platform              : Linux-5.15.152.bsk.10-amd64-x86_64-with-glibc2.36
    
==============================
       CUDA / GPU Info
==============================
Is CUDA available            : True
CUDA runtime version         : 12.9.86
CUDA_MODULE_LOADING set to   : 
GPU models and configuration : 
GPU 0: NVIDIA H800
GPU 1: NVIDIA H800
GPU 2: NVIDIA H800
GPU 3: NVIDIA H800
GPU 4: NVIDIA H800
GPU 5: NVIDIA H800
GPU 6: NVIDIA H800
GPU 7: NVIDIA H800

Nvidia driver version        : Could not collect
cuDNN version                : Probably one of the following:
/usr/lib/x86_64-linux-gnu/libcudnn.so.9.11.0
/usr/lib/x86_64-linux-gnu/libcudnn_adv.so.9.11.0
/usr/lib/x86_64-linux-gnu/libcudnn_cnn.so.9.11.0
/usr/lib/x86_64-linux-gnu/libcudnn_engines_precompiled.so.9.11.0
/usr/lib/x86_64-linux-gnu/libcudnn_engines_runtime_compiled.so.9.11.0
/usr/lib/x86_64-linux-gnu/libcudnn_graph.so.9.11.0
/usr/lib/x86_64-linux-gnu/libcudnn_heuristic.so.9.11.0
/usr/lib/x86_64-linux-gnu/libcudnn_ops.so.9.11.0
HIP runtime version          : N/A
MIOpen runtime version       : N/A
Is XNNPACK available         : True

==============================
          CPU Info
==============================
Architecture:                       x86_64
CPU op-mode(s):                     32-bit, 64-bit
Address sizes:                      52 bits physical, 57 bits virtual
Byte Order:                         Little Endian
CPU(s):                             192
On-line CPU(s) list:                0-191
Vendor ID:                          GenuineIntel
Model name:                         Intel(R) Xeon(R) Platinum 8469C
CPU family:                         6
Model:                              143
Thread(s) per core:                 2
Core(s) per socket:                 48
Socket(s):                          2
Stepping:                           8
CPU(s) scaling MHz:                 23%
CPU max MHz:                        3800.0000
CPU min MHz:                        800.0000
BogoMIPS:                           5200.00
Flags:                              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 tsc_known_freq 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 cat_l2 cdp_l3 invpcid_single intel_ppin cdp_l2 ssbd mba ibrs ibpb stibp ibrs_enhanced tpr_shadow vnmi 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 avx_vnni avx512_bf16 wbnoinvd dtherm ida arat pln pts hwp hwp_notify hwp_act_window hwp_epp hwp_pkg_req hfi avx512vbmi umip pku ospke waitpkg avx512_vbmi2 gfni vaes vpclmulqdq avx512_vnni avx512_bitalg tme avx512_vpopcntdq rdpid bus_lock_detect cldemote movdiri movdir64b enqcmd fsrm md_clear serialize tsxldtrk pconfig arch_lbr amx_bf16 avx512_fp16 amx_tile amx_int8 flush_l1d arch_capabilities
Virtualization:                     VT-x
L1d cache:                          4.5 MiB (96 instances)
L1i cache:                          3 MiB (96 instances)
L2 cache:                           192 MiB (96 instances)
L3 cache:                           195 MiB (2 instances)
NUMA node(s):                       2
NUMA node0 CPU(s):                  0-47,96-143
NUMA node1 CPU(s):                  48-95,144-191
Vulnerability Gather data sampling: Not affected
Vulnerability Itlb multihit:        Not affected
Vulnerability L1tf:                 Not affected
Vulnerability Mds:                  Not affected
Vulnerability Meltdown:             Not affected
Vulnerability Mmio stale data:      Not affected
Vulnerability Retbleed:             Not affected
Vulnerability Spec rstack overflow: Not affected
Vulnerability Spec store bypass:    Mitigation; Speculative Store Bypass disabled via prctl and seccomp
Vulnerability Spectre v1:           Mitigation; usercopy/swapgs barriers and __user pointer sanitization
Vulnerability Spectre v2:           Mitigation; Enhanced IBRS, IBPB conditional, RSB filling, PBRSB-eIBRS SW sequence
Vulnerability Srbds:                Not affected
Vulnerability Tsx async abort:      Not affected

==============================
Versions of relevant libraries
==============================
[pip3] byted-torch==2.9.1.post1
[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==4.5.0.dev0
[pip3] nvidia-cutlass-dsl-libs-base==4.5.0.dev0
[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] Could not collect

==============================
         vLLM Info
==============================
ROCM Version                 : Could not collect
vLLM Version                 : 0.19.0
vLLM Build Flags:
  CUDA Archs: Not Set; ROCm: Disabled; XPU: Disabled
GPU Topology:
        GPU0    GPU1    GPU2    GPU3    GPU4    GPU5    GPU6    GPU7    NIC0    NIC1    NIC2    NIC3    NIC4    NIC5    NIC6    NIC7    NIC8    CPU Affinity NUMA Affinity    GPU NUMA ID
GPU0     X      NV8     NV8     NV8     NV8     NV8     NV8     NV8     PIX     SYS     SYS     NODE    NODE    SYS     NODE    NODE    SYS     1-47,97-143  0N/A
GPU1    NV8      X      NV8     NV8     NV8     NV8     NV8     NV8     NODE    SYS     SYS     NODE    PIX     SYS     NODE    NODE    SYS     1-47,97-143  0N/A
GPU2    NV8     NV8      X      NV8     NV8     NV8     NV8     NV8     NODE    SYS     SYS     NODE    NODE    SYS     PIX     NODE    SYS     1-47,97-143  0N/A
GPU3    NV8     NV8     NV8      X      NV8     NV8     NV8     NV8     NODE    SYS     SYS     NODE    NODE    SYS     NODE    PIX     SYS     1-47,97-143  0N/A
GPU4    NV8     NV8     NV8     NV8      X      NV8     NV8     NV8     SYS     PIX     NODE    SYS     SYS     NODE    SYS     SYS     NODE    49-94,145-1901N/A
GPU5    NV8     NV8     NV8     NV8     NV8      X      NV8     NV8     SYS     NODE    PIX     SYS     SYS     NODE    SYS     SYS     NODE    49-94,145-1901N/A
GPU6    NV8     NV8     NV8     NV8     NV8     NV8      X      NV8     SYS     NODE    NODE    SYS     SYS     PIX     SYS     SYS     NODE    49-94,145-1901N/A
GPU7    NV8     NV8     NV8     NV8     NV8     NV8     NV8      X      SYS     NODE    NODE    SYS     SYS     NODE    SYS     SYS     PIX     49-94,145-1901N/A
NIC0    PIX     NODE    NODE    NODE    SYS     SYS     SYS     SYS      X      SYS     SYS     NODE    NODE    SYS     NODE    NODE    SYS
NIC1    SYS     SYS     SYS     SYS     PIX     NODE    NODE    NODE    SYS      X      NODE    SYS     SYS     NODE    SYS     SYS     NODE
NIC2    SYS     SYS     SYS     SYS     NODE    PIX     NODE    NODE    SYS     NODE     X      SYS     SYS     NODE    SYS     SYS     NODE
NIC3    NODE    NODE    NODE    NODE    SYS     SYS     SYS     SYS     NODE    SYS     SYS      X      NODE    SYS     NODE    NODE    SYS
NIC4    NODE    PIX     NODE    NODE    SYS     SYS     SYS     SYS     NODE    SYS     SYS     NODE     X      SYS     NODE    NODE    SYS
NIC5    SYS     SYS     SYS     SYS     NODE    NODE    PIX     NODE    SYS     NODE    NODE    SYS     SYS      X      SYS     SYS     NODE
NIC6    NODE    NODE    PIX     NODE    SYS     SYS     SYS     SYS     NODE    SYS     SYS     NODE    NODE    SYS      X      NODE    SYS
NIC7    NODE    NODE    NODE    PIX     SYS     SYS     SYS     SYS     NODE    SYS     SYS     NODE    NODE    SYS     NODE     X      SYS
NIC8    SYS     SYS     SYS     SYS     NODE    NODE    NODE    PIX     SYS     NODE    NODE    SYS     SYS     NODE    SYS     SYS      X 

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

NIC Legend:

  NIC0: mlx5_bond_0
  NIC1: mlx5_bond_1
  NIC2: mlx5_bond_2
  NIC3: mlx5_bond_3
  NIC4: mlx5_bond_4
  NIC5: mlx5_bond_5
  NIC6: mlx5_bond_6
  NIC7: mlx5_bond_7
  NIC8: mlx5_bond_8

==============================
     Environment Variables
==============================
NVIDIA_VISIBLE_DEVICES=GPU-116a4516-b0a7-15b0-6518-6f38fa3687df,GPU-1c3d4a4f-dd67-80b7-c0a6-b01cc0510c2b,GPU-46ec7145-7459-b230-bb76-d510375f6391,GPU-87a828cc-fd66-5f6f-d911-12a495ffa5c1,GPU-89351248-5ac3-e92d-7368-4205d960c86d,GPU-d33c80d2-7caa-6044-17ee-9855b7f93132,GPU-84ca4024-8e63-08a1-8453-3e01971b2440,GPU-a561abfb-6add-5c48-1f61-0fce67342038
NVIDIA_REQUIRE_CUDA=cuda>=12.1 brand=tesla,driver>=450,driver<451 brand=tesla,driver>=470,driver<471 brand=unknown,driver>=470,driver<471 brand=nvidia,driver>=470,driver<471 brand=nvidiartx,driver>=470,driver<471 brand=geforce,driver>=470,driver<471 brand=geforcertx,driver>=470,driver<471 brand=quadro,driver>=470,driver<471 brand=quadrortx,driver>=470,driver<471 brand=titan,driver>=470,driver<471 brand=titanrtx,driver>=470,driver<471 brand=tesla,driver>=510,driver<511 brand=unknown,driver>=510,driver<511 brand=nvidia,driver>=510,driver<511 brand=nvidiartx,driver>=510,driver<511 brand=geforce,driver>=510,driver<511 brand=geforcertx,driver>=510,driver<511 brand=quadro,driver>=510,driver<511 brand=quadrortx,driver>=510,driver<511 brand=titan,driver>=510,driver<511 brand=titanrtx,driver>=510,driver<511 brand=tesla,driver>=515,driver<516 brand=unknown,driver>=515,driver<516 brand=nvidia,driver>=515,driver<516 brand=nvidiartx,driver>=515,driver<516 brand=geforce,driver>=515,driver<516 brand=geforcertx,driver>=515,driver<516 brand=quadro,driver>=515,driver<516 brand=quadrortx,driver>=515,driver<516 brand=titan,driver>=515,driver<516 brand=titanrtx,driver>=515,driver<516 brand=tesla,driver>=525,driver<526 brand=unknown,driver>=525,driver<526 brand=nvidia,driver>=525,driver<526 brand=nvidiartx,driver>=525,driver<526 brand=geforce,driver>=525,driver<526 brand=geforcertx,driver>=525,driver<526 brand=quadro,driver>=525,driver<526 brand=quadrortx,driver>=525,driver<526 brand=titan,driver>=525,driver<526 brand=titanrtx,driver>=525,driver<526
VLLM_ALLOW_LONG_MAX_MODEL_LEN=1
NVIDIA_DRIVER_CAPABILITIES=compute,utility
VLLM_MARLIN_USE_ATOMIC_ADD=1
VLLM_WORKER_MULTIPROC_METHOD=spawn
PYTORCH_NPU_ALLOC_CONF=expandable_segments:True
VLLM_USE_FLASHINFER_SAMPLER=0
CUDA_DEVICE_ORDER=PCI_BUS_ID
VLLM_USE_FLASHINFER_MOE_FP16=1
LD_LIBRARY_PATH=/usr/local/cuda/lib64:
OMP_NUM_THREADS=8
CUDA_HOME=/usr/local/cuda
CUDA_HOME=/usr/local/cuda
PYTORCH_NVML_BASED_CUDA_CHECK=1
TORCHINDUCTOR_COMPILE_THREADS=1
TORCHINDUCTOR_CACHE_DIR=/tmp/torchinductor_root

---

vllm serve /home/kimi-k2.5 --served-model-name kimi-k2.5 \
  --trust-remote-code \
  --tensor-parallel-size 8 \
  --max-model-len 30000 \
  --max-num-seqs 4 \
  --gpu-memory-utilization 0.96 \
  --enable-auto-tool-choice \
  --tool-call-parser hermes \
  --reasoning-parser kimi_k2 \
  --max_num_batched_tokens 4096 \
  --enable-prefix-caching \
  --disable-custom-all-reduce \
  --kv-cache-dtype fp8 \
  --enable-expert-parallel \
  --limit-mm-per-prompt '{"image":5,"video":1}'
RAW_BUFFERClick to expand / collapse

Your current environment

<details> <summary>The output of <code>python collect_env.py</code></summary>
Collecting environment information...
==============================
        System Info
==============================
OS                           : Debian GNU/Linux 12 (bookworm) (x86_64)
GCC version                  : (Debian 12.2.0-14+deb12u1) 12.2.0
Clang version                : Could not collect
CMake version                : version 3.31.6
Libc version                 : glibc-2.36

==============================
       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
XPU used to build PyTorch    : N/A

==============================
      Python Environment
==============================
Python version               : 3.11.2 (main, Apr 28 2025, 14:11:48) [GCC 12.2.0] (64-bit runtime)
Python platform              : Linux-5.15.152.bsk.10-amd64-x86_64-with-glibc2.36
    
==============================
       CUDA / GPU Info
==============================
Is CUDA available            : True
CUDA runtime version         : 12.9.86
CUDA_MODULE_LOADING set to   : 
GPU models and configuration : 
GPU 0: NVIDIA H800
GPU 1: NVIDIA H800
GPU 2: NVIDIA H800
GPU 3: NVIDIA H800
GPU 4: NVIDIA H800
GPU 5: NVIDIA H800
GPU 6: NVIDIA H800
GPU 7: NVIDIA H800

Nvidia driver version        : Could not collect
cuDNN version                : Probably one of the following:
/usr/lib/x86_64-linux-gnu/libcudnn.so.9.11.0
/usr/lib/x86_64-linux-gnu/libcudnn_adv.so.9.11.0
/usr/lib/x86_64-linux-gnu/libcudnn_cnn.so.9.11.0
/usr/lib/x86_64-linux-gnu/libcudnn_engines_precompiled.so.9.11.0
/usr/lib/x86_64-linux-gnu/libcudnn_engines_runtime_compiled.so.9.11.0
/usr/lib/x86_64-linux-gnu/libcudnn_graph.so.9.11.0
/usr/lib/x86_64-linux-gnu/libcudnn_heuristic.so.9.11.0
/usr/lib/x86_64-linux-gnu/libcudnn_ops.so.9.11.0
HIP runtime version          : N/A
MIOpen runtime version       : N/A
Is XNNPACK available         : True

==============================
          CPU Info
==============================
Architecture:                       x86_64
CPU op-mode(s):                     32-bit, 64-bit
Address sizes:                      52 bits physical, 57 bits virtual
Byte Order:                         Little Endian
CPU(s):                             192
On-line CPU(s) list:                0-191
Vendor ID:                          GenuineIntel
Model name:                         Intel(R) Xeon(R) Platinum 8469C
CPU family:                         6
Model:                              143
Thread(s) per core:                 2
Core(s) per socket:                 48
Socket(s):                          2
Stepping:                           8
CPU(s) scaling MHz:                 23%
CPU max MHz:                        3800.0000
CPU min MHz:                        800.0000
BogoMIPS:                           5200.00
Flags:                              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 tsc_known_freq 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 cat_l2 cdp_l3 invpcid_single intel_ppin cdp_l2 ssbd mba ibrs ibpb stibp ibrs_enhanced tpr_shadow vnmi 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 avx_vnni avx512_bf16 wbnoinvd dtherm ida arat pln pts hwp hwp_notify hwp_act_window hwp_epp hwp_pkg_req hfi avx512vbmi umip pku ospke waitpkg avx512_vbmi2 gfni vaes vpclmulqdq avx512_vnni avx512_bitalg tme avx512_vpopcntdq rdpid bus_lock_detect cldemote movdiri movdir64b enqcmd fsrm md_clear serialize tsxldtrk pconfig arch_lbr amx_bf16 avx512_fp16 amx_tile amx_int8 flush_l1d arch_capabilities
Virtualization:                     VT-x
L1d cache:                          4.5 MiB (96 instances)
L1i cache:                          3 MiB (96 instances)
L2 cache:                           192 MiB (96 instances)
L3 cache:                           195 MiB (2 instances)
NUMA node(s):                       2
NUMA node0 CPU(s):                  0-47,96-143
NUMA node1 CPU(s):                  48-95,144-191
Vulnerability Gather data sampling: Not affected
Vulnerability Itlb multihit:        Not affected
Vulnerability L1tf:                 Not affected
Vulnerability Mds:                  Not affected
Vulnerability Meltdown:             Not affected
Vulnerability Mmio stale data:      Not affected
Vulnerability Retbleed:             Not affected
Vulnerability Spec rstack overflow: Not affected
Vulnerability Spec store bypass:    Mitigation; Speculative Store Bypass disabled via prctl and seccomp
Vulnerability Spectre v1:           Mitigation; usercopy/swapgs barriers and __user pointer sanitization
Vulnerability Spectre v2:           Mitigation; Enhanced IBRS, IBPB conditional, RSB filling, PBRSB-eIBRS SW sequence
Vulnerability Srbds:                Not affected
Vulnerability Tsx async abort:      Not affected

==============================
Versions of relevant libraries
==============================
[pip3] byted-torch==2.9.1.post1
[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==4.5.0.dev0
[pip3] nvidia-cutlass-dsl-libs-base==4.5.0.dev0
[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] Could not collect

==============================
         vLLM Info
==============================
ROCM Version                 : Could not collect
vLLM Version                 : 0.19.0
vLLM Build Flags:
  CUDA Archs: Not Set; ROCm: Disabled; XPU: Disabled
GPU Topology:
        GPU0    GPU1    GPU2    GPU3    GPU4    GPU5    GPU6    GPU7    NIC0    NIC1    NIC2    NIC3    NIC4    NIC5    NIC6    NIC7    NIC8    CPU Affinity NUMA Affinity    GPU NUMA ID
GPU0     X      NV8     NV8     NV8     NV8     NV8     NV8     NV8     PIX     SYS     SYS     NODE    NODE    SYS     NODE    NODE    SYS     1-47,97-143  0N/A
GPU1    NV8      X      NV8     NV8     NV8     NV8     NV8     NV8     NODE    SYS     SYS     NODE    PIX     SYS     NODE    NODE    SYS     1-47,97-143  0N/A
GPU2    NV8     NV8      X      NV8     NV8     NV8     NV8     NV8     NODE    SYS     SYS     NODE    NODE    SYS     PIX     NODE    SYS     1-47,97-143  0N/A
GPU3    NV8     NV8     NV8      X      NV8     NV8     NV8     NV8     NODE    SYS     SYS     NODE    NODE    SYS     NODE    PIX     SYS     1-47,97-143  0N/A
GPU4    NV8     NV8     NV8     NV8      X      NV8     NV8     NV8     SYS     PIX     NODE    SYS     SYS     NODE    SYS     SYS     NODE    49-94,145-1901N/A
GPU5    NV8     NV8     NV8     NV8     NV8      X      NV8     NV8     SYS     NODE    PIX     SYS     SYS     NODE    SYS     SYS     NODE    49-94,145-1901N/A
GPU6    NV8     NV8     NV8     NV8     NV8     NV8      X      NV8     SYS     NODE    NODE    SYS     SYS     PIX     SYS     SYS     NODE    49-94,145-1901N/A
GPU7    NV8     NV8     NV8     NV8     NV8     NV8     NV8      X      SYS     NODE    NODE    SYS     SYS     NODE    SYS     SYS     PIX     49-94,145-1901N/A
NIC0    PIX     NODE    NODE    NODE    SYS     SYS     SYS     SYS      X      SYS     SYS     NODE    NODE    SYS     NODE    NODE    SYS
NIC1    SYS     SYS     SYS     SYS     PIX     NODE    NODE    NODE    SYS      X      NODE    SYS     SYS     NODE    SYS     SYS     NODE
NIC2    SYS     SYS     SYS     SYS     NODE    PIX     NODE    NODE    SYS     NODE     X      SYS     SYS     NODE    SYS     SYS     NODE
NIC3    NODE    NODE    NODE    NODE    SYS     SYS     SYS     SYS     NODE    SYS     SYS      X      NODE    SYS     NODE    NODE    SYS
NIC4    NODE    PIX     NODE    NODE    SYS     SYS     SYS     SYS     NODE    SYS     SYS     NODE     X      SYS     NODE    NODE    SYS
NIC5    SYS     SYS     SYS     SYS     NODE    NODE    PIX     NODE    SYS     NODE    NODE    SYS     SYS      X      SYS     SYS     NODE
NIC6    NODE    NODE    PIX     NODE    SYS     SYS     SYS     SYS     NODE    SYS     SYS     NODE    NODE    SYS      X      NODE    SYS
NIC7    NODE    NODE    NODE    PIX     SYS     SYS     SYS     SYS     NODE    SYS     SYS     NODE    NODE    SYS     NODE     X      SYS
NIC8    SYS     SYS     SYS     SYS     NODE    NODE    NODE    PIX     SYS     NODE    NODE    SYS     SYS     NODE    SYS     SYS      X 

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

NIC Legend:

  NIC0: mlx5_bond_0
  NIC1: mlx5_bond_1
  NIC2: mlx5_bond_2
  NIC3: mlx5_bond_3
  NIC4: mlx5_bond_4
  NIC5: mlx5_bond_5
  NIC6: mlx5_bond_6
  NIC7: mlx5_bond_7
  NIC8: mlx5_bond_8

==============================
     Environment Variables
==============================
NVIDIA_VISIBLE_DEVICES=GPU-116a4516-b0a7-15b0-6518-6f38fa3687df,GPU-1c3d4a4f-dd67-80b7-c0a6-b01cc0510c2b,GPU-46ec7145-7459-b230-bb76-d510375f6391,GPU-87a828cc-fd66-5f6f-d911-12a495ffa5c1,GPU-89351248-5ac3-e92d-7368-4205d960c86d,GPU-d33c80d2-7caa-6044-17ee-9855b7f93132,GPU-84ca4024-8e63-08a1-8453-3e01971b2440,GPU-a561abfb-6add-5c48-1f61-0fce67342038
NVIDIA_REQUIRE_CUDA=cuda>=12.1 brand=tesla,driver>=450,driver<451 brand=tesla,driver>=470,driver<471 brand=unknown,driver>=470,driver<471 brand=nvidia,driver>=470,driver<471 brand=nvidiartx,driver>=470,driver<471 brand=geforce,driver>=470,driver<471 brand=geforcertx,driver>=470,driver<471 brand=quadro,driver>=470,driver<471 brand=quadrortx,driver>=470,driver<471 brand=titan,driver>=470,driver<471 brand=titanrtx,driver>=470,driver<471 brand=tesla,driver>=510,driver<511 brand=unknown,driver>=510,driver<511 brand=nvidia,driver>=510,driver<511 brand=nvidiartx,driver>=510,driver<511 brand=geforce,driver>=510,driver<511 brand=geforcertx,driver>=510,driver<511 brand=quadro,driver>=510,driver<511 brand=quadrortx,driver>=510,driver<511 brand=titan,driver>=510,driver<511 brand=titanrtx,driver>=510,driver<511 brand=tesla,driver>=515,driver<516 brand=unknown,driver>=515,driver<516 brand=nvidia,driver>=515,driver<516 brand=nvidiartx,driver>=515,driver<516 brand=geforce,driver>=515,driver<516 brand=geforcertx,driver>=515,driver<516 brand=quadro,driver>=515,driver<516 brand=quadrortx,driver>=515,driver<516 brand=titan,driver>=515,driver<516 brand=titanrtx,driver>=515,driver<516 brand=tesla,driver>=525,driver<526 brand=unknown,driver>=525,driver<526 brand=nvidia,driver>=525,driver<526 brand=nvidiartx,driver>=525,driver<526 brand=geforce,driver>=525,driver<526 brand=geforcertx,driver>=525,driver<526 brand=quadro,driver>=525,driver<526 brand=quadrortx,driver>=525,driver<526 brand=titan,driver>=525,driver<526 brand=titanrtx,driver>=525,driver<526
VLLM_ALLOW_LONG_MAX_MODEL_LEN=1
NVIDIA_DRIVER_CAPABILITIES=compute,utility
VLLM_MARLIN_USE_ATOMIC_ADD=1
VLLM_WORKER_MULTIPROC_METHOD=spawn
PYTORCH_NPU_ALLOC_CONF=expandable_segments:True
VLLM_USE_FLASHINFER_SAMPLER=0
CUDA_DEVICE_ORDER=PCI_BUS_ID
VLLM_USE_FLASHINFER_MOE_FP16=1
LD_LIBRARY_PATH=/usr/local/cuda/lib64:
OMP_NUM_THREADS=8
CUDA_HOME=/usr/local/cuda
CUDA_HOME=/usr/local/cuda
PYTORCH_NVML_BASED_CUDA_CHECK=1
TORCHINDUCTOR_COMPILE_THREADS=1
TORCHINDUCTOR_CACHE_DIR=/tmp/torchinductor_root
</details>

🐛 Describe the bug

serve command

vllm serve /home/kimi-k2.5 --served-model-name kimi-k2.5 \
  --trust-remote-code \
  --tensor-parallel-size 8 \
  --max-model-len 30000 \
  --max-num-seqs 4 \
  --gpu-memory-utilization 0.96 \
  --enable-auto-tool-choice \
  --tool-call-parser hermes \
  --reasoning-parser kimi_k2 \
  --max_num_batched_tokens 4096 \
  --enable-prefix-caching \
  --disable-custom-all-reduce \
  --kv-cache-dtype fp8 \
  --enable-expert-parallel \
  --limit-mm-per-prompt '{"image":5,"video":1}'

How to reproduce

This is not actually a reproducible issue. The occurrence is quite random every time. It happens when I conducted a long-running stress test using curl requests with a concurrency of 4.

It worked well for the first hour, but after about 1–3 hours (the timing varies each time), the service stops responding to requests. Specifically, after sending a request to the /v1/chat/completions endpoint, there is no response at all.

The request itself does not throw an error, and the service does not produce any error messages. I once tried waiting for over a day, and still no error messages appeared.

In fact, the /health, /metrics, and /tokenize endpoints all work and return responses normally. However, both /v1/chat/completions and /v1/completions hang.

From htop command, the processes appear to be running, but I observed that the EngineCore threads may have encountered a deadlock or infinite loop. From htop, the CPU usage of EngineCore is very high.

<img width="2668" height="421" alt="Image" src="https://github.com/user-attachments/assets/e464881b-23e8-418f-af79-8c5578eb762a" />

when I kill the EngineCore process I get:

<img width="3373" height="1255" alt="Image" src="https://github.com/user-attachments/assets/3d02c2e2-f761-45af-ba4d-d3fc265d37f0" />

Currently, I'm a bit at a loss. Is there any way to enable detailed logging inside EngineCore, or are there any suspected areas you can point out?

Append: I've tried other model with same params. Both GLM/Gemma work well.

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