Re: [PATCH] drm/radeon: Use kvfree instead of kfree in radeon_gpu_reset

[Christian König <christian.koenig@amd.com>]

On 5/22/26 05:32, Dawei Feng wrote:
> radeon_ring_backup() internally allocates ring_data buffers using
> kvmalloc_array(), which may use vmalloc() for large allocations. Using
> kfree() to release vmalloc-backed ring_data buffers in
> radeon_gpu_reset() will lead to memory corruption.
> 
> Use kvfree() to safely handle both kmalloc and vmalloc allocations.
> 
> The bug was first flagged by an experimental analysis tool we are
> developing for kernel memory-management bugs while analyzing
> v6.13-rc1. The tool is still under development and is not yet publicly
> available. Manual inspection confirms that the bug is still
> present in v7.1-rc3.
> 
> Runtime validation was not attempted because a targeted reproducer for
> this GPU reset error path was not available. Compile-tested only.
> 
> Fixes: 2098105ec65c ("drm: drop drm_[cm]alloc* helpers")
> Cc: stable@vger.kernel.org
> Signed-off-by: Zilin Guan <zilin@seu.edu.cn>
> Signed-off-by: Dawei Feng <dawei.feng@seu.edu.cn>

Good catch, Reviewed-by: Christian König <christian.koenig@amd.com>

> ---
>  drivers/gpu/drm/radeon/radeon_device.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/radeon/radeon_device.c b/drivers/gpu/drm/radeon/radeon_device.c
> index 705c012fcf9e..1f0f0d0eb673 100644
> --- a/drivers/gpu/drm/radeon/radeon_device.c
> +++ b/drivers/gpu/drm/radeon/radeon_device.c
> @@ -1800,7 +1800,7 @@ int radeon_gpu_reset(struct radeon_device *rdev)
>                                             ring_sizes[i], ring_data[i]);
>                 } else {
>                         radeon_fence_driver_force_completion(rdev, i);
> -                       kfree(ring_data[i]);
> +                       kvfree(ring_data[i]);
>                 }
>         }
> 
> --
> 2.34.1
>