From: "Jernej Škrabec" <jernej.skrabec@gmail.com>
To: mchehab@kernel.org, Zheng Wang <zyytlz.wz@163.com>
Cc: hverkuil@xs4all.nl, wens@csie.org, samuel@sholland.org,
linux-media@vger.kernel.org, linux-staging@lists.linux.dev,
linux-arm-kernel@lists.infradead.org,
linux-sunxi@lists.linux.dev, linux-kernel@vger.kernel.org,
hackerzheng666@gmail.com, 1395428693sheep@gmail.com,
alex000young@gmail.com, Zheng Wang <zyytlz.wz@163.com>
Subject: Re: [PATCH v2] media: cedrus: fix use after free bug in cedrus_remove due to race condition
Date: Tue, 14 Mar 2023 20:53:22 +0100 [thread overview]
Message-ID: <2274018.ElGaqSPkdT@jernej-laptop> (raw)
In-Reply-To: <20230313163120.3741811-1-zyytlz.wz@163.com>
Dne ponedeljek, 13. marec 2023 ob 17:31:20 CET je Zheng Wang napisal(a):
> In cedrus_probe, dev->watchdog_work is bound with cedrus_watchdog function.
> In cedrus_device_run, it will started by schedule_delayed_work. If there is
> an unfinished work in cedrus_remove, there may be a race condition and
> trigger UAF bug.
>
> CPU0 CPU1
>
> |cedrus_watchdog
>
> cedrus_remove |
> v4l2_m2m_release |
> kfree(m2m_dev) |
>
> | v4l2_m2m_get_curr_priv
> |
> | m2m_dev //use
>
> Fix it by canceling the worker in cedrus_remove.
>
> Fixes: 7c38a551bda1 ("media: cedrus: Add watchdog for job completion")
> Signed-off-by: Zheng Wang <zyytlz.wz@163.com>
> ---
> v2:
> - use cancel_delayed_work_sync instead and add Fixes
> label suggested by Hans Verkuil
> ---
> drivers/staging/media/sunxi/cedrus/cedrus.c | 1 +
> 1 file changed, 1 insertion(+)
>
Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Best regards,
Jernej
> diff --git a/drivers/staging/media/sunxi/cedrus/cedrus.c
> b/drivers/staging/media/sunxi/cedrus/cedrus.c index
> a43d5ff66716..a50a4d0a8f71 100644
> --- a/drivers/staging/media/sunxi/cedrus/cedrus.c
> +++ b/drivers/staging/media/sunxi/cedrus/cedrus.c
> @@ -547,6 +547,7 @@ static int cedrus_remove(struct platform_device *pdev)
> {
> struct cedrus_dev *dev = platform_get_drvdata(pdev);
>
> + cancel_delayed_work_sync(&dev->watchdog_work);
> if (media_devnode_is_registered(dev->mdev.devnode)) {
> media_device_unregister(&dev->mdev);
> v4l2_m2m_unregister_media_controller(dev->m2m_dev);
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next prev parent reply other threads:[~2023-03-14 19:54 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-13 16:31 [PATCH v2] media: cedrus: fix use after free bug in cedrus_remove due to race condition Zheng Wang
2023-03-14 19:53 ` Jernej Škrabec [this message]
2023-03-15 8:59 ` Zheng Hacker
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