On Thu, May 27, 2021 at 1:00 PM Jason Wang <jasowang@xxxxxxxxxx> wrote: > > > 在 2021/5/27 下午12:57, Yongji Xie 写道: > > On Thu, May 27, 2021 at 12:13 PM Jason Wang <jasowang@xxxxxxxxxx> wrote: > >> > >> 在 2021/5/17 下午5:55, Xie Yongji 写道: > >>> + > >>> +static int vduse_dev_msg_sync(struct vduse_dev *dev, > >>> + struct vduse_dev_msg *msg) > >>> +{ > >>> + init_waitqueue_head(&msg->waitq); > >>> + spin_lock(&dev->msg_lock); > >>> + vduse_enqueue_msg(&dev->send_list, msg); > >>> + wake_up(&dev->waitq); > >>> + spin_unlock(&dev->msg_lock); > >>> + wait_event_killable(msg->waitq, msg->completed); > >> > >> What happens if the userspace(malicous) doesn't give a response forever? > >> > >> It looks like a DOS. If yes, we need to consider a way to fix that. > >> > > How about using wait_event_killable_timeout() instead? > > > Probably, and then we need choose a suitable timeout and more important, > need to report the failure to virtio. > Makes sense to me. But it looks like some vdpa_config_ops/virtio_config_ops such as set_status() didn't have a return value. Now I add a WARN_ON() for the failure. Do you mean we need to add some change for virtio core to handle the failure? Thanks, Yongji