From 3624483d0fff933b50b91d9bd8bdd67d42b3f05e Mon Sep 17 00:00:00 2001
From: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>
Date: Tue, 24 Sep 2024 11:02:16 +0800
Subject: [PATCH] drm/amd/display: Add null checks for 'stream' and 'plane'
 before dereferencing

mainline inclusion
from mainline-v6.11-rc1
commit 15c2990e0f0108b9c3752d7072a97d45d4283aea
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAMMCZ
CVE: CVE-2024-43904

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=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@amd.com>
Cc: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Cc: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Cc: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Cc: Roman Li <roman.li@amd.com>
Cc: Hersen Wu <hersenxs.wu@amd.com>
Cc: Alex Hung <alex.hung@amd.com>
Cc: Aurabindo Pillai <aurabindo.pillai@amd.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>
Reviewed-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Conflicts:
        drivers/gpu/drm/amd/display/dc/dcn30/dcn30_hwseq.c
        drivers/gpu/drm/amd/display/dc/hwss/dcn30/dcn30_hwseq.c
[conflicts due to not mergered e53524cdcc02 ("drm/amd/display: Refactor
HWSS into component folder")]
Signed-off-by: Wang Wensheng <wangwensheng4@huawei.com>
Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com>
---
 drivers/gpu/drm/amd/display/dc/dcn30/dcn30_hwseq.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/dc/dcn30/dcn30_hwseq.c b/drivers/gpu/drm/amd/display/dc/dcn30/dcn30_hwseq.c
index ba47a1c8eec1..205bcb217e91 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn30/dcn30_hwseq.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn30/dcn30_hwseq.c
@@ -731,6 +731,9 @@ 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;
-- 
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