Re: [PATCH 2/2] virtio-net: add missing object_unref()

[Laurent Vivier <lvivier@redhat.com>]

CC: Michael

On 06/02/2021 13:39, Laurent Vivier wrote:
> failover_add_primary() calls qdev_device_add() and doesn't unref
> the device. Because of that, when the device is unplugged a reference
> is remaining and prevents the cleanup of the object.
> 
> This prevents to be able to plugin back the failover primary device,
> with errors like:
> 
>   (qemu) device_add vfio-pci,host=0000:41:00.0,id=hostdev0,bus=root.3,failover_pair_id=net0
>   (qemu) device_del hostdev0
> 
> We can check with "info qtree" and "info pci" that the device has been removed, and then:
> 
>   (qemu) device_add vfio-pci,host=0000:41:00.0,id=hostdev1,bus=root.3,failover_pair_id=net0
>   Error: vfio 0000:41:00.0: device is already attached
>   (qemu) device_add vfio-pci,host=0000:41:00.0,id=hostdev0,bus=root.3,failover_pair_id=net0
>   qemu-kvm: Duplicate ID 'hostdev0' for device
> 
> Fixes: 21e8709b29cd ("failover: Remove primary_dev member")
> Cc: quintela@redhat.com
> Signed-off-by: Laurent Vivier <lvivier@redhat.com>
> ---
>  hw/net/virtio-net.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> index 5150f295e8c5..1c5af08dc556 100644
> --- a/hw/net/virtio-net.c
> +++ b/hw/net/virtio-net.c
> @@ -862,6 +862,8 @@ static void failover_add_primary(VirtIONet *n, Error **errp)
>          dev = qdev_device_add(opts, &err);
>          if (err) {
>              qemu_opts_del(opts);
> +        } else {
> +            object_unref(OBJECT(dev));
>          }
>      } else {
>          error_setg(errp, "Primary device not found");
>