[    2.052544] ip (244) used greatest stack depth: 12384 bytes left
[    2.773041] ip (278) used greatest stack depth: 12352 bytes left
[  654.887835] ip (22340) used greatest stack depth: 12312 bytes left
[  689.208843] blackhole_netdev_xmit(): Dropping skb.
[  689.208896] blackhole_netdev_xmit(): Dropping skb.
[  689.208927] blackhole_netdev_xmit(): Dropping skb.
[  689.208960] blackhole_netdev_xmit(): Dropping skb.