Hans Verkuil <hverkuil@xxxxxxxxx> 于2023年3月13日周一 23:08写道： > > 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. > Dear Hans, Thanks for your advice. Will do in the next version of patch :) Best regards, Zheng > > > media_device_unregister(&vpu->mdev); > > hantro_remove_dec_func(vpu); > > hantro_remove_enc_func(vpu); >
