[    2.472616] ip (276) used greatest stack depth: 12320 bytes left
[   21.080323] ip (2215) used greatest stack depth: 12272 bytes left
[  953.458142] blackhole_netdev_xmit(): Dropping skb.
[  953.458267] blackhole_netdev_xmit(): Dropping skb.
[  953.458300] blackhole_netdev_xmit(): Dropping skb.
[  953.458333] blackhole_netdev_xmit(): Dropping skb.