[    1.878956] ip (244) used greatest stack depth: 12328 bytes left
[  648.413728] ip (24357) used greatest stack depth: 12168 bytes left
[ 1255.627487] blackhole_netdev_xmit(): Dropping skb.
[ 1255.627566] blackhole_netdev_xmit(): Dropping skb.
[ 1255.627601] blackhole_netdev_xmit(): Dropping skb.
[ 1255.627639] blackhole_netdev_xmit(): Dropping skb.