Re: [Qemu-devel] [PATCH for 3.1 2/4] virtio: Check qemu_get_virtqueue_element returns

[Cornelia Huck <cohuck@redhat.com>]

On Mon, 16 Jul 2018 18:37:41 +0100
"Dr. David Alan Gilbert (git)" <dgilbert@redhat.com> wrote:

> From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
> 
> Check calls to qemu_get_virtqueue_element for NULL and pass
> up the chain.
> 
> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> ---
>  hw/block/virtio-blk.c       | 4 ++++
>  hw/char/virtio-serial-bus.c | 4 ++++
>  hw/scsi/virtio-scsi.c       | 4 ++++
>  3 files changed, 12 insertions(+)
> 
> diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
> index 50b5c869e3..324c6b2b27 100644
> --- a/hw/block/virtio-blk.c
> +++ b/hw/block/virtio-blk.c
> @@ -888,6 +888,10 @@ static int virtio_blk_load_device(VirtIODevice *vdev, QEMUFile *f,
>          }
>  
>          req = qemu_get_virtqueue_element(vdev, f, sizeof(VirtIOBlockReq));
> +        if (!req) {
> +            error_report("%s: Bad vq element %u", __func__, vq_idx);

Minor nit: vq_idx is the virtqueue index, and this message makes it
look like it is the 'bad vq element'... either add 'vq index', or drop
it completely from the error message?

> +            return -EINVAL;
> +        }
>          virtio_blk_init_request(s, virtio_get_queue(vdev, vq_idx), req);
>          req->next = s->rq;
>          s->rq = req;

Anyway,
Reviewed-by: Cornelia Huck <cohuck@redhat.com>