Re: netlink: NULL timer crash

[David Miller]

From: Eric Dumazet <eric.dumazet@xxxxxxxxx>
Date: Thu, 23 Mar 2017 09:00:58 -0700

> On Thu, 2017-03-23 at 07:53 -0700, Eric Dumazet wrote:
> 
>> Nice !
>> 
>> Looks like neigh->ops->solicit is NULL
> 
> Apparently we allow admins to do really stupid things with neighbours
> on tunnels.
> 
> Following patch should avoid the crash.
> 
> Anyone has better ideas ?

This is probably good enough for now, but you need to also handle
dn_neigh_ops.

Another way to solve this is to add a NULL method check to the
one spot where we invoke this method.  That clearly shows that
the method is optional.