[    1.799548] ip (240) used greatest stack depth: 12376 bytes left
[    2.328623] ip (274) used greatest stack depth: 12344 bytes left
[  631.431593] ip (12127) used greatest stack depth: 12328 bytes left
[  642.005863] ip (13246) used greatest stack depth: 12296 bytes left
[ 1164.484511] blackhole_netdev_xmit(): Dropping skb.
[ 1164.484582] blackhole_netdev_xmit(): Dropping skb.
[ 1164.484617] blackhole_netdev_xmit(): Dropping skb.
[ 1164.484655] blackhole_netdev_xmit(): Dropping skb.
[ 1187.746604] blackhole_netdev_xmit(): Dropping skb.
[ 1187.746678] blackhole_netdev_xmit(): Dropping skb.
[ 1187.746737] blackhole_netdev_xmit(): Dropping skb.
[ 1187.746790] blackhole_netdev_xmit(): Dropping skb.