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@xxxxxxx>
---
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(+)
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);
--
2.25.1
