[PATCH] drm/amd/display: Added pointer check

[Christian König]

Am 06.12.22 um 11:47 schrieb Denis Arefev:
> Return value of a function 'dc_create_state' is
> dereferenced at amdgpu_dm.c:2027 without checking for null
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
> Signed-off-by: Denis Arefev <arefev at swemel.ru>
> ---
>   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> index 0f7749e9424d..529483997154 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> @@ -1960,7 +1960,9 @@ static int dm_resume(void *handle)
>   	dc_release_state(dm_state->context);
>   	dm_state->context = dc_create_state(dm->dc);
>   	/* TODO: Remove dc_state->dccg, use dc->dccg directly. */
> -	dc_resource_state_construct(dm->dc, dm_state->context);
> +	if (dm_state->context) {
> +		dc_resource_state_construct(dm->dc, dm_state->context);
> +	}

Single line statements shouldn't have an {} around them.

Apart from that I think error handling when dm_state->context can't be 
created would be more appropriate, but that's something our display team 
needs to look at.

Regards,
Christian.

>   
>   	/* Before powering on DC we need to re-initialize DMUB. */
>   	r = dm_dmub_hw_init(adev);