| Message ID | 20210124085552.29146-2-paul@crapouillou.net (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Fixes to bridge/panel and ingenic-drm | expand |
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)
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)
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(+)