From: Eric Dumazet <redacted>
Date: Sat, 21 Jul 2012 00:42:46 +0200

(Apparently we choke on neighbour entries count.

entries = atomic_inc_return(&tbl->entries) - 1;

We need a percpu_counter ? Or something is wrong ?

What do you mean we choke on it?  Does it exceed the thresholds
and we start garbage-collecting?

That would indicate a leak, or we are creating new neigh entries when
we shouldn't be, ie. we're not comparing the keys in the hash table
entries correctly during the lookup in net/ipv4/ip_output.c