Re: [Qemu-devel] [PATCH 1/2] virtio-9p: print error message and exit instead of BUG_ON()

[Cornelia Huck]

On Wed, 07 Sep 2016 19:19:24 +0200
Greg Kurz <address@hidden> wrote:

> Calling assert() really makes sense when hitting a genuine bug, which calls
> for a fix in QEMU. However, when something goes wrong because the guest
> sends a malformed message, it is better to write down a more meaningul
> error message and exit.
> 
> Signed-off-by: Greg Kurz <address@hidden>
> ---
>  hw/9pfs/virtio-9p-device.c |   20 ++++++++++++++++++--
>  1 file changed, 18 insertions(+), 2 deletions(-)

While this is an improvement over the current state, I don't think the
guest should be able to kill qemu just by doing something stupid.

The right way to go is to mark the virtio device as broken and stop
doing any processing until the guest resets it. I think Stefan had a
patch series doing that for some base virtio errors, but I'd have to
search for it.