From 0357d0b1f3ffcbfad1f0eabb33ac7348d9cf2cf9 Mon Sep 17 00:00:00 2001
From: Haowen Bai <baihaowen@meizu.com>
Date: Thu, 24 Mar 2022 17:27:14 +0800
Subject: drm/amd/display: Fix pointer dereferenced before checking
Git-commit: 3222a81148ca273af66cb67f8445114bc633e747
Patch-mainline: v5.19-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225

The pointer edid_buf is dereferencing pointer edid before edid is being
 null checked. Fix this by assigning edid->raw_edid to edid_buf only if
edid is not NULL, otherwise just NULL.

Signed-off-by: Haowen Bai <baihaowen@meizu.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
index f5f39984702f..28cf24f6ab32 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
@@ -90,7 +90,7 @@ enum dc_edid_status dm_helpers_parse_edid_caps(
 {
 	struct amdgpu_dm_connector *aconnector = link->priv;
 	struct drm_connector *connector = &aconnector->base;
-	struct edid *edid_buf = (struct edid *) edid->raw_edid;
+	struct edid *edid_buf = edid ? (struct edid *) edid->raw_edid : NULL;
 	struct cea_sad *sads;
 	int sad_count = -1;
 	int sadb_count = -1;
-- 
2.38.1