[PATCH 18/22] drm/amd/display: Fix slab-use-after-free on hdcp_work

[Tom Chung]

From: Mario Limonciello <mario.limonciello at amd.com>

[Why]
A slab-use-after-free is reported when HDCP is destroyed but the
property_validate_dwork queue is still running.

[How]
Cancel the delayed work when destroying workqueue.

Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/4006
Fixes: da3fd7ac0bcf ("drm/amd/display: Update CP property based on HW query")
Cc: Alex Deucher <alexander.deucher at amd.com>
Cc: stable at vger.kernel.org
Reviewed-by: Alex Hung <alex.hung at amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello at amd.com>
Signed-off-by: Tom Chung <chiahsuan.chung at amd.com>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_hdcp.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_hdcp.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_hdcp.c
index 8238cfd276be..6a4b5f4d8a9d 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_hdcp.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_hdcp.c
@@ -455,6 +455,7 @@ void hdcp_destroy(struct kobject *kobj, struct hdcp_workqueue *hdcp_work)
 	for (i = 0; i < hdcp_work->max_link; i++) {
 		cancel_delayed_work_sync(&hdcp_work[i].callback_dwork);
 		cancel_delayed_work_sync(&hdcp_work[i].watchdog_timer_dwork);
+		cancel_delayed_work_sync(&hdcp_work[i].property_validate_dwork);
 	}
 
 	sysfs_remove_bin_file(kobj, &hdcp_work[0].attr);
-- 
2.34.1