This is a note to let you know that I've just added the patch titled drm/amd/display: Fix potential null-deref in dm_resume to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: drm-amd-display-fix-potential-null-deref-in-dm_resum.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit b77d44ea035e3e709c21a0b112341bbe5c94ca27 Author: Roman Li <roman.li@xxxxxxx> Date: Thu Dec 1 09:06:42 2022 -0500 drm/amd/display: Fix potential null-deref in dm_resume [ Upstream commit 7a7175a2cd84b7874bebbf8e59f134557a34161b ] [Why] Fixing smatch error: dm_resume() error: we previously assumed 'aconnector->dc_link' could be null [How] Check if dc_link null at the beginning of the loop, so further checks can be dropped. Reported-by: kernel test robot <lkp@xxxxxxxxx> Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Reviewed-by: Wayne Lin <Wayne.Lin@xxxxxxx> Acked-by: Jasdeep Dhillon <jdhillon@xxxxxxx> Signed-off-by: Roman Li <roman.li@xxxxxxx> Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> 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 9fd711005c1f5..1e7083bc8a527 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -1206,12 +1206,14 @@ static int dm_resume(void *handle) list_for_each_entry(connector, &ddev->mode_config.connector_list, head) { aconnector = to_amdgpu_dm_connector(connector); + if (!aconnector->dc_link) + continue; + /* * this is the case when traversing through already created * MST connectors, should be skipped */ - if (aconnector->dc_link && - aconnector->dc_link->type == dc_connection_mst_branch) + if (aconnector->dc_link->type == dc_connection_mst_branch) continue; mutex_lock(&aconnector->hpd_lock);