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Date: Fri, 20 Mar 2015 13:53:04 +0800
From: Jason Wang <jasowang@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH for 2.3 2/2] virtio-net: fix the upper
 bound when trying to delete queues
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To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: qemu-devel@nongnu.org, qemu-stable <qemu-stable@nongnu.org>



On Thu, Mar 19, 2015 at 6:12 PM, Michael S. Tsirkin <mst@redhat.com> 
wrote:
> On Thu, Mar 19, 2015 at 03:05:52PM +0800, Jason Wang wrote:
>>  Virtqueue were indexed from zero, so don't delete virtqueue whose
>>  index is n->max_queues * 2 + 1.
> 
> But what's the current behaviour?
> 
> Can it lead to aborts? virtio_del_queue does:
>     if (n < 0 || n >= VIRTIO_PCI_QUEUE_MAX) {
>         abort();
>     }

Yes, it will hit abort() above.
> 
> 
> 
>>  Cc: Michael S. Tsirkin <mst@redhat.com>
>>  Cc: qemu-stable <qemu-stable@nongnu.org>
>>  Signed-off-by: Jason Wang <jasowang@redhat.com>
>>  ---
>>   hw/net/virtio-net.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>  
>>  diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
>>  index 59f76bc..b6fac9c 100644
>>  --- a/hw/net/virtio-net.c
>>  +++ b/hw/net/virtio-net.c
>>  @@ -1309,7 +1309,7 @@ static void 
>> virtio_net_set_multiqueue(VirtIONet *n, int multiqueue)
>>   
>>       n->multiqueue = multiqueue;
>>   
>>  -    for (i = 2; i <= n->max_queues * 2 + 1; i++) {
>>  +    for (i = 2; i < n->max_queues * 2 + 1; i++) {
>>           virtio_del_queue(vdev, i);
>>       }
>>   
>>  -- 
>>  2.1.0
>