[    2.354297] ip (277) used greatest stack depth: 12320 bytes left
[  631.687322] ip (2565) used greatest stack depth: 12304 bytes left
[  633.870024] ip (2806) used greatest stack depth: 12272 bytes left
[  799.889068] blackhole_netdev_xmit(): Dropping skb.
[  799.889123] blackhole_netdev_xmit(): Dropping skb.
[  799.889160] blackhole_netdev_xmit(): Dropping skb.
[  799.889194] blackhole_netdev_xmit(): Dropping skb.