[Bug]: rocm build crashes with libcuda.so.1: cannot open shared object file

[mobicham]

Your current environment

The output of python collect_env.py

==============================
       PyTorch Info  
==============================
PyTorch version              : 2.8.0.dev20250615+rocm6.4
Is debug build               : False
CUDA used to build PyTorch   : N/A
ROCM used to build PyTorch   : 6.4.43482-0f2d60242

==============================
       CUDA / GPU Info
==============================
Is CUDA available            : True
CUDA runtime version         : Could not collect
CUDA_MODULE_LOADING set to   : LAZY
GPU models and configuration : AMD Instinct MI300X (gfx942:sramecc+:xnack-)
Nvidia driver version        : Could not collect
cuDNN version                : Could not collect
HIP runtime version          : 6.4.43482
MIOpen runtime version       : 3.4.0
Is XNNPACK available         : True

==============================
         vLLM Info   
==============================
ROCM Version                 : 6.4.43483-a187df25c
Neuron SDK Version           : N/A
vLLM Version                 : 0.9.2.dev95+g26bc46ef8.d20250616 (git sha: 26bc46ef8, date: 20250616)

🐛 Describe the bug

The current branch crashes with rocm:

libcuda.so.1: cannot open shared object file

The issue is here, it doesn't check for hip: https://github.com/vllm-project/vllm/blob/main/vllm/device_allocator/cumem.py#L48-L64

Replacing it with something like this solves the issue:

cumem_available = False
try:
    if torch.version.hip:
        raise RuntimeError("Skipping CuMemAllocator on ROCm platform")
    
    from vllm.cumem_allocator import (init_module, python_create_and_map, python_unmap_and_release)
    from vllm.distributed.device_communicators.cuda_wrapper import (CudaRTLibrary)
    lib_name = find_loaded_library("cumem_allocator")
    cumem_available = lib_name is not None
except Exception:
    # rocm platform does not support cumem allocator
    init_module = None
    python_create_and_map = None
    python_unmap_and_release = None
    CudaRTLibrary = None
    lib_name = None
    libcudart = None

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[hongxiayang]

This does not seem to be new code, and wonder why you had a crash: https://github.com/vllm-project/vllm/blob/main/vllm/device_allocator/cumem.py#L48-L64

How did you build your vllm?
How to reproduce ?

[mobicham]

I built it via:

pip install --pre torch torchvision torchaudio --index-url https://download.pytorch.org/whl/nightly/rocm6.4;
pip install <other dependencies> 
PYTORCH_ROCM_ARCH="gfx942" pip install --no-build-isolation -e . ; 

after removing torch from the toml file