Patch "drm/amd/display: Add null checks for 'stream' and 'plane' before dereferencing" has been added to the 6.10-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 null checks for 'stream' and 'plane' before dereferencing

to the 6.10-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-null-checks-for-stream-and-plane.patch
and it can be found in the queue-6.10 subdirectory.

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



commit 867f093dea3e42437521b9dd2c3c9dddf17d07de
Author: Srinivasan Shanmugam <srinivasan.shanmugam@xxxxxxx>
Date:   Mon May 27 20:15:21 2024 +0530

    drm/amd/display: Add null checks for 'stream' and 'plane' before dereferencing
    
    [ Upstream commit 15c2990e0f0108b9c3752d7072a97d45d4283aea ]
    
    This commit adds null checks for the 'stream' and 'plane' variables in
    the dcn30_apply_idle_power_optimizations function. These variables were
    previously assumed to be null at line 922, but they were used later in
    the code without checking if they were null. This could potentially lead
    to a null pointer dereference, which would cause a crash.
    
    The null checks ensure that 'stream' and 'plane' are not null before
    they are used, preventing potential crashes.
    
    Fixes the below static smatch checker:
    drivers/gpu/drm/amd/amdgpu/../display/dc/hwss/dcn30/dcn30_hwseq.c:938 dcn30_apply_idle_power_optimizations() error: we previously assumed 'stream' could be null (see line 922)
    drivers/gpu/drm/amd/amdgpu/../display/dc/hwss/dcn30/dcn30_hwseq.c:940 dcn30_apply_idle_power_optimizations() error: we previously assumed 'plane' could be null (see line 922)
    
    Cc: Tom Chung <chiahsuan.chung@xxxxxxx>
    Cc: Nicholas Kazlauskas <nicholas.kazlauskas@xxxxxxx>
    Cc: Bhawanpreet Lakha <Bhawanpreet.Lakha@xxxxxxx>
    Cc: Rodrigo Siqueira <Rodrigo.Siqueira@xxxxxxx>
    Cc: Roman Li <roman.li@xxxxxxx>
    Cc: Hersen Wu <hersenxs.wu@xxxxxxx>
    Cc: Alex Hung <alex.hung@xxxxxxx>
    Cc: Aurabindo Pillai <aurabindo.pillai@xxxxxxx>
    Cc: Harry Wentland <harry.wentland@xxxxxxx>
    Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@xxxxxxx>
    Reviewed-by: Aurabindo Pillai <aurabindo.pillai@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/hwss/dcn30/dcn30_hwseq.c b/drivers/gpu/drm/amd/display/dc/hwss/dcn30/dcn30_hwseq.c
index ed9141a67db37..5b09d95cc5b8f 100644
--- a/drivers/gpu/drm/amd/display/dc/hwss/dcn30/dcn30_hwseq.c
+++ b/drivers/gpu/drm/amd/display/dc/hwss/dcn30/dcn30_hwseq.c
@@ -919,6 +919,9 @@ bool dcn30_apply_idle_power_optimizations(struct dc *dc, bool enable)
 			stream = dc->current_state->streams[0];
 			plane = (stream ? dc->current_state->stream_status[0].plane_states[0] : NULL);
 
+			if (!stream || !plane)
+				return false;
+
 			if (stream && plane) {
 				cursor_cache_enable = stream->cursor_position.enable &&
 						plane->address.grph.cursor_cache_addr.quad_part;