From: Zheng Wang zyytlz.wz@163.com
[ Upstream commit 3228cec23b8b29215e18090c6ba635840190993d ]
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@163.com Signed-off-by: Hans Verkuil hverkuil-cisco@xs4all.nl Signed-off-by: Mauro Carvalho Chehab mchehab@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 7bab7586918c1..82806f198074a 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);