[    1.868600] ip (239) used greatest stack depth: 12832 bytes left
[    1.919344] ip (245) used greatest stack depth: 12352 bytes left
[    2.342037] ip (274) used greatest stack depth: 12320 bytes left
[  627.416661] ip (7358) used greatest stack depth: 12256 bytes left
[  946.799043] blackhole_netdev_xmit(): Dropping skb.
[  946.799115] blackhole_netdev_xmit(): Dropping skb.
[  946.799144] blackhole_netdev_xmit(): Dropping skb.
[  946.799171] blackhole_netdev_xmit(): Dropping skb.