From fa56f5f1fe31c2050675fa63b84963ebd504a5b3 Mon Sep 17 00:00:00 2001
From: Yang Yingliang <yangyingliang@huawei.com>
Date: Tue, 6 Apr 2021 15:42:46 +0200
Subject: [PATCH] media: adv7604: fix possible use-after-free in adv76xx_remove()
Git-commit: fa56f5f1fe31c2050675fa63b84963ebd504a5b3
Patch-mainline: v5.13-rc1
References: git-fixes

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>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/media/i2c/adv7604.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/media/i2c/adv7604.c b/drivers/media/i2c/adv7604.c
index 10418574a89c..3049aa2fd0f0 100644
--- a/drivers/media/i2c/adv7604.c
+++ b/drivers/media/i2c/adv7604.c
@@ -3670,7 +3670,7 @@ static int adv76xx_remove(struct i2c_client *client)
 	io_write(sd, 0x6e, 0);
 	io_write(sd, 0x73, 0);
 
-	cancel_delayed_work(&state->delayed_work_enable_hotplug);
+	cancel_delayed_work_sync(&state->delayed_work_enable_hotplug);
 	v4l2_async_unregister_subdev(sd);
 	media_entity_cleanup(&sd->entity);
 	adv76xx_unregister_clients(to_state(sd));
-- 
2.26.2