linux-kernel - [PATCH AUTOSEL 6.6 092/139] drm/amd/display: Check null pointers before using dc->clk

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Message-ID: <20240925121137.1307574-92-sashal@kernel.org>
Date: Wed, 25 Sep 2024 08:08:32 -0400
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org,
	stable@...r.kernel.org
Cc: Alex Hung <alex.hung@....com>,
	Rodrigo Siqueira <rodrigo.siqueira@....com>,
	Tom Chung <chiahsuan.chung@....com>,
	Daniel Wheeler <daniel.wheeler@....com>,
	Alex Deucher <alexander.deucher@....com>,
	Sasha Levin <sashal@...nel.org>,
	harry.wentland@....com,
	sunpeng.li@....com,
	Rodrigo.Siqueira@....com,
	christian.koenig@....com,
	Xinhui.Pan@....com,
	airlied@...il.com,
	daniel@...ll.ch,
	alvin.lee2@....com,
	wayne.lin@....com,
	wenjing.liu@....com,
	sungjoon.kim@....com,
	aurabindo.pillai@....com,
	dillon.varone@....com,
	amd-gfx@...ts.freedesktop.org,
	dri-devel@...ts.freedesktop.org
Subject: [PATCH AUTOSEL 6.6 092/139] drm/amd/display: Check null pointers before using dc->clk_mgr

From: Alex Hung <alex.hung@....com>

[ Upstream commit 95d9e0803e51d5a24276b7643b244c7477daf463 ]

[WHY & HOW]
dc->clk_mgr is null checked previously in the same function, indicating
it might be null.

Passing "dc" to "dc->hwss.apply_idle_power_optimizations", which
dereferences null "dc->clk_mgr". (The function pointer resolves to
"dcn35_apply_idle_power_optimizations".)

This fixes 1 FORWARD_NULL issue reported by Coverity.

Reviewed-by: Rodrigo Siqueira <rodrigo.siqueira@....com>
Signed-off-by: Alex Hung <alex.hung@....com>
Signed-off-by: Tom Chung <chiahsuan.chung@....com>
Tested-by: Daniel Wheeler <daniel.wheeler@....com>
Signed-off-by: Alex Deucher <alexander.deucher@....com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/gpu/drm/amd/display/dc/core/dc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/dc/core/dc.c b/drivers/gpu/drm/amd/display/dc/core/dc.c
index 0b2eb2a6c8e14..a7a6f6c5c7655 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc.c
@@ -4716,7 +4716,8 @@ void dc_allow_idle_optimizations(struct dc *dc, bool allow)
 	if (allow == dc->idle_optimizations_allowed)
 		return;
 
-	if (dc->hwss.apply_idle_power_optimizations && dc->hwss.apply_idle_power_optimizations(dc, allow))
+	if (dc->hwss.apply_idle_power_optimizations && dc->clk_mgr != NULL &&
+	    dc->hwss.apply_idle_power_optimizations(dc, allow))
 		dc->idle_optimizations_allowed = allow;
 }
 
-- 
2.43.0