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

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

[Srinivasan Shanmugam]

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) {
 
-- 
2.34.1

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

[Aurabindo Pillai]

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>

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

[SRINIVASAN SHANMUGAM]

On 1/8/2024 9:58 PM, Aurabindo Pillai wrote:
>
>
> 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.

Sure Jay!, thanks for reviews! will add this in description.

Best regards,

Srini

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