Patch "drm/amd/display: Add 'replay' NULL check in 'edp_set_replay_allow_active()'" has been added to the 6.6-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    drm/amd/display: Add 'replay' NULL check in 'edp_set_replay_allow_active()'

to the 6.6-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     drm-amd-display-add-replay-null-check-in-edp_set_rep.patch
and it can be found in the queue-6.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 5aa8a2ccd0844d9e0a3517f1d5a5fa7a097d0a50
Author: Srinivasan Shanmugam <srinivasan.shanmugam@xxxxxxx>
Date:   Thu Feb 15 18:38:16 2024 +0530

    drm/amd/display: Add 'replay' NULL check in 'edp_set_replay_allow_active()'
    
    [ Upstream commit f6aed043ee5d75b3d1bfc452b1a9584b63c8f76b ]
    
    In the first if statement, we're checking if 'replay' is NULL. But in
    the second if statement, we're not checking if 'replay' is NULL again
    before calling replay->funcs->replay_set_power_opt().
    
    if (replay == NULL && force_static)
        return false;
    
    ...
    
    if (link->replay_settings.replay_feature_enabled &&
        replay->funcs->replay_set_power_opt) {
            replay->funcs->replay_set_power_opt(replay, *power_opts, panel_inst);
            link->replay_settings.replay_power_opt_active = *power_opts;
    }
    
    If 'replay' is NULL, this will cause a null pointer dereference.
    
    Fixes the below found by smatch:
    drivers/gpu/drm/amd/amdgpu/../display/dc/link/protocols/link_edp_panel_control.c:895 edp_set_replay_allow_active() error: we previously assumed 'replay' could be null (see line 887)
    
    Fixes: c7ddc0a800bc ("drm/amd/display: Add Functions to enable Freesync Panel Replay")
    Cc: Bhawanpreet Lakha <Bhawanpreet.Lakha@xxxxxxx>
    Cc: Roman Li <roman.li@xxxxxxx>
    Cc: Rodrigo Siqueira <Rodrigo.Siqueira@xxxxxxx>
    Cc: Aurabindo Pillai <aurabindo.pillai@xxxxxxx>
    Cc: Tom Chung <chiahsuan.chung@xxxxxxx>
    Suggested-by: Tom Chung <chiahsuan.chung@xxxxxxx>
    Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@xxxxxxx>
    Reviewed-by: Tom Chung <chiahsuan.chung@xxxxxxx>
    Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

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 6f64aab18f07b..13104d000b9e0 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
@@ -882,7 +882,8 @@ bool edp_set_replay_allow_active(struct dc_link *link, const bool *allow_active,
 
 	/* Set power optimization flag */
 	if (power_opts && link->replay_settings.replay_power_opt_active != *power_opts) {
-		if (link->replay_settings.replay_feature_enabled && replay->funcs->replay_set_power_opt) {
+		if (replay != NULL && link->replay_settings.replay_feature_enabled &&
+		    replay->funcs->replay_set_power_opt) {
 			replay->funcs->replay_set_power_opt(replay, *power_opts, panel_inst);
 			link->replay_settings.replay_power_opt_active = *power_opts;
 		}