[    2.734959] ip (275) used greatest stack depth: 12320 bytes left
[  640.370619] ip (22233) used greatest stack depth: 12304 bytes left
[ 1193.317239] blackhole_netdev_xmit(): Dropping skb.
[ 1193.317300] blackhole_netdev_xmit(): Dropping skb.
[ 1193.317333] blackhole_netdev_xmit(): Dropping skb.
[ 1193.317379] blackhole_netdev_xmit(): Dropping skb.