From: Zheng Wang Date: Mon, 13 Mar 2023 16:31:20 +0000 (+0000) Subject: media: cedrus: fix use after free bug in cedrus_remove due to race condition X-Git-Tag: v6.6.17~5047^2~307 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=50d0a7aea4809cef87979d4669911276aa23b71f;p=platform%2Fkernel%2Flinux-rpi.git media: cedrus: fix use after free bug in cedrus_remove due to race condition 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 Acked-by: Jernej Skrabec Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- diff --git a/drivers/staging/media/sunxi/cedrus/cedrus.c b/drivers/staging/media/sunxi/cedrus/cedrus.c index a43d5ff..a50a4d0 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);