Re: [PATCH next] drm/amdgpu/userqueue: Fix use after free in amdgpu_userq_buffer_vas_list_cleanup()

[Alex Deucher <alexdeucher@gmail.com>]

Applied.  Thanks!

Alex

On Wed, Oct 22, 2025 at 9:31 AM Dan Carpenter <dan.carpenter@linaro.org> wrote:
>
> The amdgpu_userq_buffer_va_list_del() function frees "va_cursor" but it
> is dereferenced on the next line when we print the debug message.  Print
> the debug message first and then free it.
>
> Fixes: 2a28f9665dca ("drm/amdgpu: track the userq bo va for its obj management")
> Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c
> index 9d4751a39c20..2200e0bbf040 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c
> @@ -159,9 +159,9 @@ static int amdgpu_userq_buffer_vas_list_cleanup(struct amdgpu_device *adev,
>                         r = -EINVAL;
>                         goto err;
>                 }
> -               amdgpu_userq_buffer_va_list_del(mapping, va_cursor);
>                 dev_dbg(adev->dev, "delete the userq:%p va:%llx\n",
>                         queue, va_cursor->gpu_addr);
> +               amdgpu_userq_buffer_va_list_del(mapping, va_cursor);
>         }
>  err:
>         amdgpu_bo_unreserve(queue->vm->root.bo);
> --
> 2.51.0
>