[PATCH 5.10.y] drm/amd/display: Add null checker before passing variables

[Vasiliy Kovalev <kovalev@altlinux.org>]

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

commit 8092aa3ab8f7b737a34b71f91492c676a843043a upstream.

Checks null pointer before passing variables to functions.

This fixes 3 NULL_RETURNS issues reported by Coverity.

Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Acked-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Fixes: cdaae8371aa9 ("drm/amd/display: Handle GPU reset for DC block")
Fixes: dcd5fb82ffb4 ("drm/amd/display: Fix reference counting for struct dc_sink.")
Fixes: 4562236b3bc0 ("drm/amd/dc: Add dc display driver (v2)")
[ kovalev: bp to fix CVE-2024-43902; added Fixes tags ]
Signed-off-by: Vasiliy Kovalev <kovalev@altlinux.org>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

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 c22783b88206..bd15de4dee75 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -1778,7 +1778,8 @@ static int dm_suspend(void *handle)
 		mutex_lock(&dm->dc_lock);
 		dm->cached_dc_state = dc_copy_state(dm->dc->current_state);
 
-		dm_gpureset_toggle_interrupts(adev, dm->cached_dc_state, false);
+		if (dm->cached_dc_state)
+			dm_gpureset_toggle_interrupts(adev, dm->cached_dc_state, false);
 
 		amdgpu_dm_commit_zero_streams(dm->dc);
 
@@ -5396,7 +5397,8 @@ static void create_eml_sink(struct amdgpu_dm_connector *aconnector)
 		aconnector->dc_sink = aconnector->dc_link->local_sink ?
 		aconnector->dc_link->local_sink :
 		aconnector->dc_em_sink;
-		dc_sink_retain(aconnector->dc_sink);
+		if (aconnector->dc_sink)
+			dc_sink_retain(aconnector->dc_sink);
 	}
 }
 
@@ -6575,7 +6577,8 @@ static int amdgpu_dm_connector_get_modes(struct drm_connector *connector)
 				drm_add_modes_noedid(connector, 640, 480);
 	} else {
 		amdgpu_dm_connector_ddc_get_modes(connector, edid);
-		amdgpu_dm_connector_add_common_modes(encoder, connector);
+		if (encoder)
+			amdgpu_dm_connector_add_common_modes(encoder, connector);
 	}
 	amdgpu_dm_fbc_init(connector);
 
-- 
2.50.1