[    2.467118] ip (272) used greatest stack depth: 12344 bytes left
[   21.519333] ip (2180) used greatest stack depth: 12328 bytes left
[  644.801931] ip (7193) used greatest stack depth: 12184 bytes left
[ 1215.703617] blackhole_netdev_xmit(): Dropping skb.
[ 1215.703707] blackhole_netdev_xmit(): Dropping skb.
[ 1215.703751] blackhole_netdev_xmit(): Dropping skb.
[ 1215.703803] blackhole_netdev_xmit(): Dropping skb.