From: David Ahern <dsah...@kernel.org>
Date: Wed, 1 May 2019 18:18:42 -0700
> From: David Ahern <dsah...@gmail.com>
>
> Commit cd9ff4de0107 changed the key for IFF_POINTOPOINT devices to
> INADDR_ANY but neigh_xmit which is used for MPLS encapsulations was not
> updated to use the altered key. The result is that every packet Tx does
> a lookup on the gateway address which does not find an entry, a new one
> is created only to find the existing one in the table right before the
> insert since arp_constructor was updated to reset the primary key. This
> is seen in the allocs and destroys counters:
> ip -s -4 ntable show | head -10 | grep alloc
>
> which increase for each packet showing the unnecessary overhread.
>
> Fix by having neigh_xmit use __ipv4_neigh_lookup_noref for NEIGH_ARP_TABLE.
>
> Fixes: cd9ff4de0107 ("ipv4: Make neigh lookup keys for
> loopback/point-to-point devices be INADDR_ANY")
> Reported-by: Alan Maguire <alan.magu...@oracle.com>
> Signed-off-by: David Ahern <dsah...@gmail.com>
Applied and queued up for -stable.
