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
v3: Add FIXME
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 | 12 ++++++++++++ 1 file changed, 12 insertions(+)
diff --git a/drivers/gpu/drm/bridge/panel.c b/drivers/gpu/drm/bridge/panel.c index 0ddc37551194..5959e8183cd0 100644 --- a/drivers/gpu/drm/bridge/panel.c +++ b/drivers/gpu/drm/bridge/panel.c @@ -87,6 +87,18 @@ 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. + * + * FIXME: This wouldn't be needed if the panel_bridge structure was + * allocated with drmm_kzalloc(). This might be tricky since the + * drm_device pointer can only be retrieved when the bridge is attached. + */ + if (!!panel_bridge->connector.dev) + drm_connector_cleanup(connector); }
static void panel_bridge_pre_enable(struct drm_bridge *bridge)
Hi Paul,
Thank you for the patch.
On Sun, Jan 24, 2021 at 08:55:49AM +0000, Paul Cercueil 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.
v2: Cleanup connector only if it was created
v3: Add FIXME
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 | 12 ++++++++++++ 1 file changed, 12 insertions(+)
diff --git a/drivers/gpu/drm/bridge/panel.c b/drivers/gpu/drm/bridge/panel.c index 0ddc37551194..5959e8183cd0 100644 --- a/drivers/gpu/drm/bridge/panel.c +++ b/drivers/gpu/drm/bridge/panel.c @@ -87,6 +87,18 @@ 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.** FIXME: This wouldn't be needed if the panel_bridge structure was* allocated with drmm_kzalloc(). This might be tricky since the* drm_device pointer can only be retrieved when the bridge is attached.*/- if (!!panel_bridge->connector.dev)
How about simply
if (connector->dev)
? With this change,
Reviewed-by: Laurent Pinchart laurent.pinchart@ideasonboard.com
drm_connector_cleanup(connector);} static void panel_bridge_pre_enable(struct drm_bridge *bridge)
linux-stable-mirror@lists.linaro.org
-
Laurent Pinchart -
Paul Cercueil