Re: [PATCH] drm/amdgpu: Use kvfree instead of kfree in amdgpu_gmc_get_nps_memranges()

[Christian König]

On 1/29/26 10:05, Zilin Guan wrote:
> amdgpu_discovery_get_nps_info() internally allocates memory for ranges
> using kvcalloc(), which may use vmalloc() for large allocation. Using
> kfree() to release vmalloc memory will lead to a memory corruption.
> 
> Use kvfree() to safely handle both kmalloc and vmalloc allocations.
> 
> Compile tested only. Issue found using a prototype static analysis tool
> and code review.
> 
> Fixes: b194d21b9bcc ("drm/amdgpu: Use NPS ranges from discovery table")
> Signed-off-by: Zilin Guan <zi...@seu.edu.cn>

Good catch!

But i think we rather need to question why amdgpu_discovery_get_nps_info() is 
using kvcalloc()? I have strong doubts that we need vmalloc() here.

Regards,
Christian.

> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c 
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c
> index 7e623f91f2d7..cb0d1ac148e9 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c
> @@ -1382,7 +1382,7 @@ int amdgpu_gmc_get_nps_memranges(struct amdgpu_device 
> *adev,
>       if (!*exp_ranges)
>               *exp_ranges = range_cnt;
>  err:
> -     kfree(ranges);
> +     kvfree(ranges);
>  
>       return ret;
>  }