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From:   Paul Cercueil <paul@crapouillou.net>
To:     David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>
Cc:     Sam Ravnborg <sam@ravnborg.org>, od@zcrc.me,
        dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
        Paul Cercueil <paul@crapouillou.net>, stable@vger.kernel.org,
        Andrzej Hajda <a.hajda@samsung.com>,
        Neil Armstrong <narmstrong@baylibre.com>,
        Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
        Jonas Karlman <jonas@kwiboo.se>,
        Jernej Skrabec <jernej.skrabec@siol.net>
Subject: [PATCH 1/3] drm: bridge/panel: Cleanup connector on bridge detach
Date:   Sun, 17 Jan 2021 11:26:44 +0000
Message-Id: <20210117112646.98353-2-paul@crapouillou.net>
In-Reply-To: <20210117112646.98353-1-paul@crapouillou.net>
References: <20210117112646.98353-1-paul@crapouillou.net>
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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.

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 | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/bridge/panel.c b/drivers/gpu/drm/bridge/panel.c
index 0ddc37551194..975d65c14c9c 100644
--- a/drivers/gpu/drm/bridge/panel.c
+++ b/drivers/gpu/drm/bridge/panel.c
@@ -87,6 +87,10 @@ 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;
+
+	drm_connector_cleanup(connector);
 }
 
 static void panel_bridge_pre_enable(struct drm_bridge *bridge)
-- 
2.29.2