From 10cd2bf92b4cf64a9c044f2c9774461e526d526a Mon Sep 17 00:00:00 2001 From: Srinivasan Shanmugam Date: Tue, 6 Feb 2024 09:34:25 +0530 Subject: drm/amd/display: Fix possible NULL dereference on device remove/driver unload As part of a cleanup amdgpu_dm_fini() function, which is typically called when a device is being shut down or a driver is being unloaded The below error message suggests that there is a potential null pointer dereference issue with adev->dm.dc. In the below, line of code where adev->dm.dc is used without a preceding null check: for (i = 0; i < adev->dm.dc->caps.max_links; i++) { To fix this issue, add a null check for adev->dm.dc before this line. Reported by smatch: drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:1959 amdgpu_dm_fini() error: we previously assumed 'adev->dm.dc' could be null (see line 1943) Fixes: 006c26a0f1c8 ("drm/amd/display: Fix crash on device remove/driver unload") Cc: Andrey Grodzovsky Cc: Harry Wentland Cc: Rodrigo Siqueira Cc: Aurabindo Pillai Signed-off-by: Srinivasan Shanmugam Reviewed-by: Roman Li Reviewed-by: Aurabindo Pillai Signed-off-by: Alex Deucher --- drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/gpu/drm/amd/display/amdgpu_dm') 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 367868ad20d7..a2220d4787fb 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -1955,7 +1955,7 @@ static void amdgpu_dm_fini(struct amdgpu_device *adev) &adev->dm.dmub_bo_gpu_addr, &adev->dm.dmub_bo_cpu_addr); - if (adev->dm.hpd_rx_offload_wq) { + if (adev->dm.hpd_rx_offload_wq && adev->dm.dc) { for (i = 0; i < adev->dm.dc->caps.max_links; i++) { if (adev->dm.hpd_rx_offload_wq[i].wq) { destroy_workqueue(adev->dm.hpd_rx_offload_wq[i].wq); -- cgit v1.2.3