Re: [PATCH] drm/amd/display: Fix variable deferencing before NULL check in edp_setup_replay()

[Aurabindo Pillai <aurabindo.pillai@amd.com>]

On 2024-01-08 11:19, Srinivasan Shanmugam wrote:
> In edp_setup_replay(), 'struct dc *dc' & 'struct dmub_replay *replay'
> was dereferenced before the pointer 'link' & 'replay' NULL check.
> 
> Fixes the below:
> drivers/gpu/drm/amd/amdgpu/../display/dc/link/protocols/link_edp_panel_control.c:947 edp_setup_replay() warn: variable dereferenced before check 'link' (see line 933)
> 
> Cc: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
> Cc: Harry Wentland <harry.wentland@amd.com>
> Cc: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
> Cc: Aurabindo Pillai <aurabindo.pillai@amd.com>
> Cc: Alex Deucher <alexander.deucher@amd.com>
> Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>
> ---
>   .../dc/link/protocols/link_edp_panel_control.c        | 11 +++++++----
>   1 file changed, 7 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/display/dc/link/protocols/link_edp_panel_control.c b/drivers/gpu/drm/amd/display/dc/link/protocols/link_edp_panel_control.c
> index 7f1196528218..046d3e205415 100644
> --- a/drivers/gpu/drm/amd/display/dc/link/protocols/link_edp_panel_control.c
> +++ b/drivers/gpu/drm/amd/display/dc/link/protocols/link_edp_panel_control.c
> @@ -930,8 +930,8 @@ bool edp_get_replay_state(const struct dc_link *link, uint64_t *state)
>   bool edp_setup_replay(struct dc_link *link, const struct dc_stream_state *stream)
>   {
>   	/* To-do: Setup Replay */
> -	struct dc *dc = link->ctx->dc;
> -	struct dmub_replay *replay = dc->res_pool->replay;
> +	struct dc *dc;
> +	struct dmub_replay *replay;
>   	int i;
>   	unsigned int panel_inst;
>   	struct replay_context replay_context = { 0 };
> @@ -947,6 +947,10 @@ bool edp_setup_replay(struct dc_link *link, const struct dc_stream_state *stream
>   	if (!link)
>   		return false;
>   
> +	dc = link->ctx->dc;
> +
> +	replay = dc->res_pool->replay;
> +
>   	if (!replay)
>   		return false;
>   
> @@ -975,8 +979,7 @@ bool edp_setup_replay(struct dc_link *link, const struct dc_stream_state *stream
>   
>   	replay_context.line_time_in_ns = lineTimeInNs;
>   
> -	if (replay)
> -		link->replay_settings.replay_feature_enabled =
> +	link->replay_settings.replay_feature_enabled =
>   			replay->funcs->replay_copy_settings(replay, link, &replay_context, panel_inst);
>   	if (link->replay_settings.replay_feature_enabled) {
>   

Please add Cc: stable@vger.kernel.org in description.

Reviewed-by: Aurabindo Pillai <aurabindo.pillai@amd.com>