drm: bridge/panel: Cleanup connector on bridge detach

stable inclusion
from stable-v5.10.37
commit ce450934a00cf896e648fde08d0bd1426653d7a2
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I94VOL
CVE: CVE-2021-47063

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=ce450934a00cf896e648fde08d0bd1426653d7a2



--------------------------------

commit 4d906839 upstream.

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

v4: (Use connector->dev) directly in if() block

Fixes: 13dfc054 ("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>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210327115742.18986-2-paul@crapouillou.net


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

conflicts:
	drivers/gpu/drm/bridge/panel.c

Signed-off-by: Guo Mengqi <guomengqi3@huawei.com>