Le mer. 20 janv. 2021 à 17:03, Daniel Vetter daniel@ffwll.ch a écrit :
On Wed, Jan 20, 2021 at 1:35 PM Paul Cercueil paul@crapouillou.net wrote:
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.
For -fixes this sounds ok, but for -next I think switching to drmm_ would be much better.
The API would need to change to have access to the drm_device struct, though. That would be quite a big patch, there are a few dozens source files that use this API already.
Cheers, -Paul
v2: Cleanup connector only if it was created
Fixes: 13dfc0540a57 ("drm/bridge: Refactor out the panel wrapper from the lvds-encoder bridge.") Cc: stable@vger.kernel.org # 4.12+ Cc: Andrzej Hajda a.hajda@samsung.com Cc: Neil Armstrong narmstrong@baylibre.com Cc: Laurent Pinchart Laurent.pinchart@ideasonboard.com Cc: Jonas Karlman jonas@kwiboo.se Cc: Jernej Skrabec jernej.skrabec@siol.net Signed-off-by: Paul Cercueil paul@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
-- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch