Re: [PATCH net V2 3/4] Revert "net: vhost: lock the vqs one by one"

Jason Wang
2018-12-13T02:27:39Z

On 2018/12/12 下午10:24, Michael S. Tsirkin wrote:
> On Wed, Dec 12, 2018 at 06:08:18PM +0800, Jason Wang wrote:
>> This reverts commit 78139c94dc8c96a478e67dab3bee84dc6eccb5fd. We don't
>> protect device IOTLB with vq mutex, which will lead e.g use after free
>> for device IOTLB entries. And since we've switched to use
>> mutex_trylock() in previous patch, it's safe to revert it without
>> having deadlock.
>>
>> Fixes: commit 78139c94dc8c ("net: vhost: lock the vqs one by one")
>> Cc: Tonghao Zhang<xiangxia.m.yue@gmail.com>
>> Signed-off-by: Jason Wang<jasowang@redhat.com>
> Acked-by: Michael S. Tsirkin<mst@redhat.com>
>
> I'd try to put this in 4.20 if we can
> and it's needed for -stable I think.
>
> Also looks like we should allow iotlb entries per vq
> to improve locking. What do you think?
>

Yes, we can do it for -next.

Thanks