In rkvdec_probe, rkvdec->watchdog_work is bound with
rkvdec_watchdog_func. Then rkvdec_vp9_run may
be called to start the work.
If we remove the module which will call rkvdec_remove
to make cleanup, there may be a unfinished work.
The possible sequence is as follows, which will
cause a typical UAF bug.
Fix it by canceling the work before cleanup in rkvdec_remove.
CPU0 CPU1
|rkvdec_watchdog_func
rkvdec_remove |
rkvdec_v4l2_cleanup|
v4l2_m2m_release |
kfree(m2m_dev); |
|
| v4l2_m2m_get_curr_priv
| m2m_dev->curr_ctx //use
Fixes: cd33c830448b ("media: rkvdec: Add the rkvdec driver")
Signed-off-by: Zheng Wang <zyytlz.wz@xxxxxxx>
---
v2:
- use cancel_delayed_work_sync instead of cancel_delayed_work suggested Hans Verkuil
---
drivers/staging/media/rkvdec/rkvdec.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/staging/media/rkvdec/rkvdec.c b/drivers/staging/media/rkvdec/rkvdec.c
index 7bab7586918c..82806f198074 100644
--- a/drivers/staging/media/rkvdec/rkvdec.c
+++ b/drivers/staging/media/rkvdec/rkvdec.c
@@ -1066,6 +1066,8 @@ static int rkvdec_remove(struct platform_device *pdev)
{
struct rkvdec_dev *rkvdec = platform_get_drvdata(pdev);
+ cancel_delayed_work_sync(&rkvdec->watchdog_work);
+
rkvdec_v4l2_cleanup(rkvdec);
pm_runtime_disable(&pdev->dev);
pm_runtime_dont_use_autosuspend(&pdev->dev);
--
2.25.1
