[    2.589525] ip (277) used greatest stack depth: 12352 bytes left
[    2.812462] ip (291) used greatest stack depth: 12336 bytes left
[    7.729872] ip (621) used greatest stack depth: 12320 bytes left
[   13.611569] ip (1077) used greatest stack depth: 12280 bytes left
[  756.237485] blackhole_netdev_xmit(): Dropping skb.
[  756.237561] blackhole_netdev_xmit(): Dropping skb.
[  756.237595] blackhole_netdev_xmit(): Dropping skb.
[  756.237633] blackhole_netdev_xmit(): Dropping skb.