[    1.818684] ip (243) used greatest stack depth: 12352 bytes left
[    2.335176] ip (277) used greatest stack depth: 12320 bytes left
[    4.667617] ip (412) used greatest stack depth: 12304 bytes left
[  629.426221] ip (30653) used greatest stack depth: 12160 bytes left
[ 1148.558719] blackhole_netdev_xmit(): Dropping skb.
[ 1148.558783] blackhole_netdev_xmit(): Dropping skb.
[ 1148.558816] blackhole_netdev_xmit(): Dropping skb.
[ 1148.558853] blackhole_netdev_xmit(): Dropping skb.