Re: [Qemu-devel] [PATCH] virtio: validate the existence of handle_output before calling it

[Jason Wang]

On Sat, Feb 14, 2015 at 4:50 AM, Paolo Bonzini <address@hidden> 
wrote:
> On 12/02/2015 04:05, Jason Wang wrote:
> >  We don't validate the existence of handle_output which may let a 
> > buggy
> >  guest to trigger a SIGSEV easily. Fix this by validate its existence
> >  before.
> >  
> >  Cc: address@hidden
> >  Cc: Anthony Liguori <address@hidden>
> >  Cc: Michael S. Tsirkin <address@hidden>
> >  Signed-off-by: Jason Wang <address@hidden>
>
> Which queue was causing this?
>
> Paolo

The queue that was not used by the device. Though qemu does not use 
them, but it allows guest to do some basic programming. e.g: (for 1q 
virtio-net)

1) write 10 to queue_sel
2) setup an arbitrary pfn
3) then notify queue 10