[    2.030579] ip (240) used greatest stack depth: 12832 bytes left
[    2.069868] ip (243) used greatest stack depth: 12352 bytes left
[    2.741269] ip (274) used greatest stack depth: 12320 bytes left
[   15.787420] ip (1366) used greatest stack depth: 12304 bytes left
[  631.403522] ip (21232) used greatest stack depth: 12272 bytes left
[  926.520373] blackhole_netdev_xmit(): Dropping skb.
[  926.520429] blackhole_netdev_xmit(): Dropping skb.
[  926.520456] blackhole_netdev_xmit(): Dropping skb.
[  926.520490] blackhole_netdev_xmit(): Dropping skb.