[    7.985989] ip (951) used greatest stack depth: 12160 bytes left
[    9.831476] ip (1175) used greatest stack depth: 12048 bytes left
[  683.007051] blackhole_netdev_xmit(): Dropping skb.
[  683.007111] blackhole_netdev_xmit(): Dropping skb.
[  683.007142] blackhole_netdev_xmit(): Dropping skb.
[  683.007173] blackhole_netdev_xmit(): Dropping skb.