Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider: - [High] Missing cleanup of `drm_backlight_link()` on probe error paths causes a Use-After-Free on a global list and a reference leak. --
commit a0dd986fcfc01d36a6bb91afe25a294e80d0f4e6 Author: Mario Limonciello <[email protected]> drm/bridge: auto-link panel backlight in bridge connector This commit links a panel's backlight_device to the bridge connector so luminance-aware clients can drive it through the LUMINANCE property. > diff --git a/drivers/gpu/drm/display/drm_bridge_connector.c > b/drivers/gpu/drm/display/drm_bridge_connector.c > index 8b54069fa53a4..d4b4e59cea51c 100644 > --- a/drivers/gpu/drm/display/drm_bridge_connector.c > +++ b/drivers/gpu/drm/display/drm_bridge_connector.c [ ... ] > @@ -1082,9 +1084,16 @@ struct drm_connector *drm_bridge_connector_init(struct > drm_device *drm, > connector->polled = DRM_CONNECTOR_POLL_CONNECT > | DRM_CONNECTOR_POLL_DISCONNECT; > > - if (panel_bridge) > + if (panel_bridge) { > + struct drm_panel *panel; > + > drm_panel_bridge_set_orientation(connector, panel_bridge); > > + panel = drm_panel_bridge_to_panel(panel_bridge); > + if (panel && panel->backlight) > + drm_backlight_link(connector, panel->backlight); [Severity: High] Does this cause a use-after-free and a reference leak on probe error paths? During early initialization here, drm_backlight_link() links the connector's backlight to the global list. If the driver's probe function subsequently fails before calling drm_dev_register() (e.g., due to EPROBE_DEFER or hardware errors), the device is never registered. Because drm_connector_unregister() is never called in this error path, the backlight is not unlinked. Later, when drmm managed cleanup runs drm_connector_cleanup(), it calls drm_backlight_connector_cleanup(). Looking at drm_backlight_connector_cleanup(): void drm_backlight_connector_cleanup(struct drm_connector *connector) { struct drm_backlight *b = &connector->backlight; WARN_ON(__drm_backlight_is_linked(b)); WARN_ON(b->funcs); WARN_ON(b->luminance_clients); } This function only warns and does not actually unlink the backlight. The connector is then freed, leaving a dangling pointer in the global drm_backlight_list. Iterating this global list later (e.g., during backlight brightness changes) could dereference the freed connector memory. > + } > + > if (support_hdcp && IS_REACHABLE(CONFIG_DRM_DISPLAY_HELPER) && > IS_ENABLED(CONFIG_DRM_DISPLAY_HDCP_HELPER)) > drm_connector_attach_content_protection_property(connector, > true); -- Sashiko AI review · https://sashiko.dev/#/patchset/[email protected]?part=9
