nbio_v7_4: Add pointer check

[Limonciello, Mario]

On 11/10/2022 06:28, Denis Arefev wrote:
> Return value of a function 'amdgpu_ras_find_obj' is dereferenced at nbio_v7_4.c:325 without checking for null

This line is too long, you should be wrapping lines at 75 characters.
Could you run your patch through checkpatch?

> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 
> Signed-off-by: Denis Arefev <arefev at swemel.ru>

Probably should include this tag:

Fixes: 28f87950d935e ("drm/amdgpu: clear ras controller status registers 
when interrupt occurs")

> ---
>   drivers/gpu/drm/amd/amdgpu/nbio_v7_4.c | 3 +++
>   1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/nbio_v7_4.c b/drivers/gpu/drm/amd/amdgpu/nbio_v7_4.c
> index eadc9526d33f..0f2ac99de864 100644
> --- a/drivers/gpu/drm/amd/amdgpu/nbio_v7_4.c
> +++ b/drivers/gpu/drm/amd/amdgpu/nbio_v7_4.c
> @@ -304,6 +304,9 @@ static void nbio_v7_4_handle_ras_controller_intr_no_bifring(struct amdgpu_device
>   	struct ras_err_data err_data = {0, 0, 0, NULL};
>   	struct amdgpu_ras *ras = amdgpu_ras_get_context(adev);
>   
> +	if (!obj)
> +	  return;
>   

Whitespace seems inconsistent here.

>   	bif_doorbell_intr_cntl = RREG32_SOC15(NBIO, 0, mmBIF_DOORBELL_INT_CNTL);
>   	if (REG_GET_FIELD(bif_doorbell_intr_cntl,
>   		BIF_DOORBELL_INT_CNTL, RAS_CNTLR_INTERRUPT_STATUS)) {