media: tc358743: fix possible use-after-free in tc358743_remove()

This driver's remove path calls cancel_delayed_work(). However, that
function does not wait until the work function finishes. This means
that the callback function may still be running after the driver's
remove function has finished, which would result in a use-after-free.

Fix by calling cancel_delayed_work_sync(), which ensures that
the work is properly cancelled, no longer running, and unable
to re-schedule itself.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

diff --git a/drivers/media/i2c/tc358743.c b/drivers/media/i2c/tc358743.c
index 831b5b54fd78c0e75bb7c847641740135e1e5b57..1b309bb743c7bd7452705606e831319209acf8be 100644 (file)
--- a/drivers/media/i2c/tc358743.c
+++ b/drivers/media/i2c/tc358743.c
@@ -2193,7 +2193,7 @@ static int tc358743_remove(struct i2c_client *client)
                del_timer_sync(&state->timer);
                flush_work(&state->work_i2c_poll);
        }
-       cancel_delayed_work(&state->delayed_work_enable_hotplug);
+       cancel_delayed_work_sync(&state->delayed_work_enable_hotplug);
        cec_unregister_adapter(state->cec_adap);
        v4l2_async_unregister_subdev(sd);
        v4l2_device_unregister_subdev(sd);