[    1.923590] ip (243) used greatest stack depth: 12304 bytes left
[  973.004619] blackhole_netdev_xmit(): Dropping skb.
[  973.004682] blackhole_netdev_xmit(): Dropping skb.
[  973.004712] blackhole_netdev_xmit(): Dropping skb.
[  973.004746] blackhole_netdev_xmit(): Dropping skb.