From: Mario Limonciello <mario.limonciello@amd.com>
Date: Thu, 24 Jul 2025 20:00:43 +0000 (-0500)
Subject: drm/amd/display: Avoid a NULL pointer dereference
X-Git-Tag: v6.16.4~192
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=0c1a486cbe6f9cb194e3c4a8ade4af2a642ba165;p=thirdparty%2Fkernel%2Fstable.git

drm/amd/display: Avoid a NULL pointer dereference

commit 07b93a5704b0b72002f0c4bd1076214af67dc661 upstream.

[WHY]
Although unlikely drm_atomic_get_new_connector_state() or
drm_atomic_get_old_connector_state() can return NULL.

[HOW]
Check returns before dereference.

Cc: Mario Limonciello <mario.limonciello@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Alex Hung <alex.hung@amd.com>
Tested-by: Dan Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 1e5e8d672fec9f2ab352be121be971877bff2af9)
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index c0a2cf9ba6a26..2d94fec5b545d 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -7761,6 +7761,9 @@ amdgpu_dm_connector_atomic_check(struct drm_connector *conn,
 	struct amdgpu_dm_connector *aconn = to_amdgpu_dm_connector(conn);
 	int ret;
 
+	if (WARN_ON(unlikely(!old_con_state || !new_con_state)))
+		return -EINVAL;
+
 	trace_amdgpu_dm_connector_atomic_check(new_con_state);
 
 	if (conn->connector_type == DRM_MODE_CONNECTOR_DisplayPort) {