[    1.922240] ip (244) used greatest stack depth: 12360 bytes left
[    2.613227] ip (278) used greatest stack depth: 12344 bytes left
[    2.840069] ip (292) used greatest stack depth: 12328 bytes left
[    5.496290] ip (413) used greatest stack depth: 12312 bytes left
[   14.226126] ip (1171) used greatest stack depth: 12288 bytes left
[  927.548212] blackhole_netdev_xmit(): Dropping skb.
[  927.548273] blackhole_netdev_xmit(): Dropping skb.
[  927.548308] blackhole_netdev_xmit(): Dropping skb.
[  927.548346] blackhole_netdev_xmit(): Dropping skb.