Hi Chris,

On Tue, Dec 26, 2017 at 01:49:59AM +0000, Chris Rankin wrote:
(...)
> [   35.100181] Call Trace:
> [   35.102709]  dump_stack+0x46/0x59
> [   35.106095]  check_preemption_disabled+0xca/0xda
> [   35.110786]  ip6_pol_route+0x46b/0x509 [ipv6]
(...)

One patch touched this area between 4.14.8 and 4.14.9, you may try
to revert it to see if it fixes the issue :

    9704f81 ("ipv6: grab rt->rt6i_ref before allocating pcpu rt")

Willy