On 07/03/2023 16:41, Zheng Wang wrote: > In hantro_probe, vpu->watchdog_work is bound with > hantro_watchdog. Then hantro_end_prepare_run may > be called to start the work. > > If we close the file or remove the module which will > call hantro_release and hantro_remove to make cleanup, > there may be a unfinished work. The possible sequence > is as follows, which will cause a typical UAF bug. > > The same thing will happen in hantro_release, and use > ctx after freeing it. > > Fix it by canceling the work before cleanup in hantro_release. > > CPU0 CPU1 > > |hantro_watchdog > hantro_remove | > v4l2_m2m_release | > kfree(m2m_dev); | > | > | v4l2_m2m_get_curr_priv > | m2m_dev->curr_ctx //use > > Signed-off-by: Zheng Wang <zyytlz.wz@xxxxxxx> > --- > drivers/media/platform/verisilicon/hantro_drv.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/media/platform/verisilicon/hantro_drv.c b/drivers/media/platform/verisilicon/hantro_drv.c > index b0aeedae7b65..80bd856a4da9 100644 > --- a/drivers/media/platform/verisilicon/hantro_drv.c > +++ b/drivers/media/platform/verisilicon/hantro_drv.c > @@ -1099,6 +1099,7 @@ static int hantro_remove(struct platform_device *pdev) > > v4l2_info(&vpu->v4l2_dev, "Removing %s\n", pdev->name); > > + cancel_delayed_work(&vpu->watchdog_work); Use cancel_delayed_work_sync(): that ensures the code waits for a running watchdog function to finish. Ditto for the other patch. Regards, Hans > media_device_unregister(&vpu->mdev); > hantro_remove_dec_func(vpu); > hantro_remove_enc_func(vpu);
