[    2.063294] ip (275) used greatest stack depth: 12320 bytes left
[  637.472529] ip (7075) used greatest stack depth: 12272 bytes left
[ 1121.692857] blackhole_netdev_xmit(): Dropping skb.
[ 1121.692935] blackhole_netdev_xmit(): Dropping skb.
[ 1121.692983] blackhole_netdev_xmit(): Dropping skb.
[ 1121.693034] blackhole_netdev_xmit(): Dropping skb.