[    1.900497] ip (238) used greatest stack depth: 12376 bytes left
[    2.502718] ip (272) used greatest stack depth: 12344 bytes left
[  633.879705] ip (9669) used greatest stack depth: 12328 bytes left
[  643.129064] ip (10687) used greatest stack depth: 12296 bytes left
[ 1123.362433] blackhole_netdev_xmit(): Dropping skb.
[ 1123.362494] blackhole_netdev_xmit(): Dropping skb.
[ 1123.362529] blackhole_netdev_xmit(): Dropping skb.
[ 1123.362563] blackhole_netdev_xmit(): Dropping skb.