Re: [Qemu-devel] [PATCH] vhost-scsi: prevent using uninitialized vqs

[yuchenlin <yuchenlin@synology.com>]

Ping?

On 2018-10-12 17:07, yuchenlin@synology.com wrote:
> From: yuchenlin <yuchenlin@synology.com>
> 
> There are 3 virtqueues (ctrl, event and cmd) for virtio scsi device,
> but seabios will only set the physical address for the 3rd one (cmd).
> Then in vhost_virtqueue_start(), virtio_queue_get_desc_addr()
> will be 0 for ctrl and event vq.
> 
> In this case, ctrl and event vq are not initialized.
> vhost_verify_ring_mappings may use uninitialized vhost_virtqueue
> such that vhost_verify_ring_part_mapping returns ENOMEM.
> 
> When encountered this problem, we got the following logs:
> 
>     qemu-system-x86_64: Unable to map available ring for ring 0
>     qemu-system-x86_64: Verify ring failure on region 0
> 
> Signed-off-by: Forrest Liu <forrestl@synology.com>
> Signed-off-by: yuchenlin <yuchenlin@synology.com>
> ---
>  hw/scsi/vhost-scsi.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/hw/scsi/vhost-scsi.c b/hw/scsi/vhost-scsi.c
> index becf550085..7f21b4f9d6 100644
> --- a/hw/scsi/vhost-scsi.c
> +++ b/hw/scsi/vhost-scsi.c
> @@ -183,7 +183,7 @@ static void vhost_scsi_realize(DeviceState *dev,
> Error **errp)
>      }
> 
>      vsc->dev.nvqs = VHOST_SCSI_VQ_NUM_FIXED + vs->conf.num_queues;
> -    vsc->dev.vqs = g_new(struct vhost_virtqueue, vsc->dev.nvqs);
> +    vsc->dev.vqs = g_new0(struct vhost_virtqueue, vsc->dev.nvqs);
>      vsc->dev.vq_index = 0;
>      vsc->dev.backend_features = 0;