Re: [Qemu-stable] [2.2 PATCH V2] virtio-net: fix unmap leak

[Peter Maydell]

On 27 November 2014 at 12:42, Peter Maydell <address@hidden> wrote:
> On 27 November 2014 at 12:33, Michael S. Tsirkin <address@hidden> wrote:
>> On Thu, Nov 27, 2014 at 06:04:03PM +0800, Jason Wang wrote:
>>> virtio_net_handle_ctrl() and other functions that process control vq
>>> request call iov_discard_front() which will shorten the iov. This will
>>> lead unmapping in virtqueue_push() leaks mapping.
>>>
>>> Fixes this by keeping the original iov untouched and using a temp variable
>>> in those functions.
>>>
>>> Cc: Wen Congyang <address@hidden>
>>> Cc: Stefano Stabellini <address@hidden>
>>> Cc: address@hidden
>>> Signed-off-by: Jason Wang <address@hidden>
>>
>> Reviewed-by: Michael S. Tsirkin <address@hidden>
>>
>> Peter, can you pick this up or do you want a pull request?
>
> I can pick it up. I was waiting a bit to check that everybody
> was happy that this is the correct way to fix the bug and the
> patch is ok...

...but discussing this with Stefan H on IRC we realised that the same
issue also (at least potentially) affects virtio-blk, which suggests
that we should fix this by making the core virtio code cope with
backends which modify the sglists.

-- PMM