Linux Virtualization - May 2021 - [PATCH v7 11/12] vduse: Introduce VDUSE - vDPA Device in Userspace

? 2021/5/27 ??12:57, Yongji Xie ??:
> On Thu, May 27, 2021 at 12:13 PM Jason Wang <jasowang at redhat.com>
wrote:
>>
>> ? 2021/5/17 ??5:55, Xie Yongji ??:
>>> +
>>> +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.

Thanks

>
> Thanks,
> Yongji
>