[PATCH v2 1/3] drm: bridge/panel: Cleanup connector on bridge detach

[Paul Cercueil]

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.

v2: Cleanup connector only if it was created

Fixes: 13dfc0540a57 ("drm/bridge: Refactor out the panel wrapper from the lvds-encoder bridge.")
Cc: <stable at vger.kernel.org> # 4.12+
Cc: Andrzej Hajda <a.hajda at samsung.com>
Cc: Neil Armstrong <narmstrong at baylibre.com>
Cc: Laurent Pinchart <Laurent.pinchart at ideasonboard.com>
Cc: Jonas Karlman <jonas at kwiboo.se>
Cc: Jernej Skrabec <jernej.skrabec at siol.net>
Signed-off-by: Paul Cercueil <paul at crapouillou.net>
---
 drivers/gpu/drm/bridge/panel.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/bridge/panel.c b/drivers/gpu/drm/bridge/panel.c
index 0ddc37551194..df86b0ee0549 100644
--- a/drivers/gpu/drm/bridge/panel.c
+++ b/drivers/gpu/drm/bridge/panel.c
@@ -87,6 +87,12 @@ 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;
+
+	/* Cleanup the connector if we know it was initialized */
+	if (!!panel_bridge->connector.dev)
+		drm_connector_cleanup(connector);
 }
 
 static void panel_bridge_pre_enable(struct drm_bridge *bridge)
-- 
2.29.2