[PATCH 1/3] drm: bridge/panel: Cleanup connector on bridge detach

From: Paul Cercueil
Date: Sun Jan 17 2021 - 06:28:53 EST

If we don't call drm_connector_cleanup() manually in
panel_bridge_detach(), the connector will be cleaned up with the other
DRM objects in the call to drm_mode_config_cleanup(). However, since our
drm_connector is devm-allocated, by the time drm_mode_config_cleanup()
will be called, our connector will be long gone. Therefore, the
connector must be cleaned up when the bridge is detached to avoid
use-after-free conditions.

Fixes: 13dfc0540a57 ("drm/bridge: Refactor out the panel wrapper from the lvds-encoder bridge.")
Cc: <stable@xxxxxxxxxxxxxxx> # 4.12+
Cc: Andrzej Hajda <a.hajda@xxxxxxxxxxx>
Cc: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
Cc: Laurent Pinchart <Laurent.pinchart@xxxxxxxxxxxxxxxx>
Cc: Jonas Karlman <jonas@xxxxxxxxx>
Cc: Jernej Skrabec <jernej.skrabec@xxxxxxxx>
Signed-off-by: Paul Cercueil <paul@xxxxxxxxxxxxxxx>
drivers/gpu/drm/bridge/panel.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/bridge/panel.c b/drivers/gpu/drm/bridge/panel.c
index 0ddc37551194..975d65c14c9c 100644
--- a/drivers/gpu/drm/bridge/panel.c
+++ b/drivers/gpu/drm/bridge/panel.c
@@ -87,6 +87,10 @@ static int panel_bridge_attach(struct drm_bridge *bridge,

static void panel_bridge_detach(struct drm_bridge *bridge)
+ struct panel_bridge *panel_bridge = drm_bridge_to_panel_bridge(bridge);
+ struct drm_connector *connector = &panel_bridge->connector;
+ drm_connector_cleanup(connector);

static void panel_bridge_pre_enable(struct drm_bridge *bridge)