ValueError when running LongWriter-GLM4-9B with vLLM on Kaggle T4 GPUs

[WpythonW]

System Info / 系統信息

Python version: 3.10
Hardware: 2x NVIDIA T4 GPUs (Kaggle environment)
CUDA: Latest available on Kaggle
vLLM: Latest (installed via pip with --force-reinstall)
Model: THUDM/LongWriter-glm4-9b
Platform: Kaggle Notebooks

Who can help? / 谁可以帮助到您？

No response

Information / 问题信息

• The official example scripts / 官方的示例脚本
• My own modified scripts / 我自己修改的脚本和任务

Reproduction / 复现过程

The error occurs when trying to run LongWriter-GLM4-9B with tensor parallelism across 2 T4 GPUs. Here's the minimal reproduction code:

from vllm import LLM, SamplingParams

model = LLM(
    model="THUDM/LongWriter-glm4-9b",
    dtype="half",
    trust_remote_code=True,
    tensor_parallel_size=2,
    max_model_len=32768,
    gpu_memory_utilization=1,
)

tokenizer = model.get_tokenizer()
stop_token_ids = [tokenizer.eos_token_id, tokenizer.get_command("<|user|>"), tokenizer.get_command("<|observation|>")]

generation_params = SamplingParams(
    temperature=0.5,
    top_p=0.8,
    top_k=50,
    max_tokens=32768,
    repetition_penalty=1,
    stop_token_ids=stop_token_ids
)

query = "Write a 10000-word China travel guide"
input_ids = tokenizer.build_chat_input(query, history=[], role='user').input_ids[0].tolist()
outputs = model.generate(
    sampling_params=generation_params,
    prompt_token_ids=[input_ids],
)

Error message:

ValueError: could not broadcast input array from shape (513,) into shape (512,)

Full traceback shows the error occurs in /vllm/attention/backends/utils.py, line 215, during the attention metadata building process.

Expected behavior / 期待表现

The model should:

1. Successfully load and initialize across both T4 GPUs using tensor parallelism
2. Accept the input prompt and generate text using the specified parameters
3. Handle the attention mechanism correctly without shape mismatches