[PATCH] Staging: drivers/gpu/drm/amd/amdgpu: Fix null pointer deference in amdkfd_fence_get_timeline_name

[Christian König]

Am 20.09.24 um 11:09 schrieb Dipendra Khadka:
> '''
> drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_fence.c:108:9: error: Null pointer dereference: fence [nullPointer]
>   return fence->timeline_name;
>          ^
> '''
>
> The method to_amdgpu_amdkfd_fence can return NULL incase of empty f
> or f->ops != &amdkfd_fence_ops.Hence, check has been added .
> If fence is null , then null is returned.

Well NAK, completely nonsense. Calling the function with a NULL fence is 
illegal.

Regards,
Christian.

>
> Signed-off-by: Dipendra Khadka <kdipendra88 at gmail.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_fence.c | 3 +++
>   1 file changed, 3 insertions(+)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_fence.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_fence.c
> index 1ef758ac5076..2313babcc944 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_fence.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_fence.c
> @@ -105,6 +105,9 @@ static const char *amdkfd_fence_get_timeline_name(struct dma_fence *f)
>   {
>   	struct amdgpu_amdkfd_fence *fence = to_amdgpu_amdkfd_fence(f);
>   
> +	if (!fence)
> +		return NULL;
> +
>   	return fence->timeline_name;
>   }
>