[    1.860633] ip (243) used greatest stack depth: 12352 bytes left
[    2.360512] ip (277) used greatest stack depth: 12320 bytes left
[  626.777555] ip (18644) used greatest stack depth: 12272 bytes left
[  842.512801] blackhole_netdev_xmit(): Dropping skb.
[  842.512855] blackhole_netdev_xmit(): Dropping skb.
[  842.512883] blackhole_netdev_xmit(): Dropping skb.
[  842.512909] blackhole_netdev_xmit(): Dropping skb.