From be5799e667218086aa1f8543e628b64e97e770c9 Mon Sep 17 00:00:00 2001
From: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>
Date: Tue, 26 Nov 2024 18:10:51 +0800
Subject: [PATCH] drm/amd/display: Add NULL check for function pointer in
 dcn32_set_output_transfer_func

[ Upstream commit 28574b08c70e56d34d6f6379326a860b96749051 ]

This commit adds a null check for the set_output_gamma function pointer
in the dcn32_set_output_transfer_func function. Previously,
set_output_gamma was being checked for null, but then it was being
dereferenced without any null check. This could lead to a null pointer
dereference if set_output_gamma is null.

To fix this, we now ensure that set_output_gamma is not null before
dereferencing it. We do this by adding a null check for set_output_gamma
before the call to set_output_gamma.

Cc: Tom Chung <chiahsuan.chung@amd.com>
Cc: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Cc: Roman Li <roman.li@amd.com>
Cc: Alex Hung <alex.hung@amd.com>
Cc: Aurabindo Pillai <aurabindo.pillai@amd.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>
Reviewed-by: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Xiangyu Chen <xiangyu.chen@windriver.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
(cherry picked from commit f38b09ba6a335c511eb27920bb9bb4a1b2c20084)
---
 drivers/gpu/drm/amd/display/dc/dcn32/dcn32_hwseq.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dcn32/dcn32_hwseq.c b/drivers/gpu/drm/amd/display/dc/dcn32/dcn32_hwseq.c
index 650e1598bddcb..2289c17f6ead5 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn32/dcn32_hwseq.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn32/dcn32_hwseq.c
@@ -587,7 +587,9 @@ bool dcn32_set_output_transfer_func(struct dc *dc,
 		}
 	}
 
-	mpc->funcs->set_output_gamma(mpc, mpcc_id, params);
+	if (mpc->funcs->set_output_gamma)
+		mpc->funcs->set_output_gamma(mpc, mpcc_id, params);
+
 	return ret;
 }