drm_panel_bridge_add_typed() stores a pointer to the drm_panel it wraps, but never acquires a reference to it. If the panel device goes away while a panel_bridge still exists, the dangling pointer can be dereferenced through panel_bridge->panel.
Acquire a reference in drm_panel_bridge_add_typed() with drm_panel_get() and release it in each teardown path. Signed-off-by: Albert Esteve <[email protected]> --- drivers/gpu/drm/bridge/panel.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/bridge/panel.c b/drivers/gpu/drm/bridge/panel.c index 4978ec98a0828..6b98ad19508df 100644 --- a/drivers/gpu/drm/bridge/panel.c +++ b/drivers/gpu/drm/bridge/panel.c @@ -294,7 +294,7 @@ struct drm_bridge *drm_panel_bridge_add_typed(struct drm_panel *panel, return (void *)panel_bridge; panel_bridge->connector_type = connector_type; - panel_bridge->panel = panel; + panel_bridge->panel = drm_panel_get(panel); panel_bridge->bridge.of_node = panel->dev->of_node; panel_bridge->bridge.ops = DRM_BRIDGE_OP_MODES; @@ -316,6 +316,7 @@ EXPORT_SYMBOL(drm_panel_bridge_add_typed); void drm_panel_bridge_remove(struct drm_bridge *bridge) { struct panel_bridge *panel_bridge; + struct drm_panel *panel; if (!bridge) return; @@ -326,10 +327,12 @@ void drm_panel_bridge_remove(struct drm_bridge *bridge) } panel_bridge = drm_bridge_to_panel_bridge(bridge); + panel = panel_bridge->panel; drm_bridge_remove(bridge); /* TODO remove this after reworking panel_bridge lifetime */ - devm_drm_put_bridge(panel_bridge->panel->dev, bridge); + devm_drm_put_bridge(panel->dev, bridge); + drm_panel_put(panel); } EXPORT_SYMBOL(drm_panel_bridge_remove); @@ -357,11 +360,14 @@ EXPORT_SYMBOL(drm_panel_bridge_set_orientation); static void devm_drm_panel_bridge_release(struct device *dev, void *res) { struct drm_bridge *bridge = *(struct drm_bridge **)res; + struct panel_bridge *panel_bridge; if (!bridge) return; + panel_bridge = drm_bridge_to_panel_bridge(bridge); drm_bridge_remove(bridge); + drm_panel_put(panel_bridge->panel); } /** -- 2.54.0
