Re: net/ipv6: GPF in rt6_device_match

[Cong Wang]

On Wed, May 3, 2017 at 11:22 AM, David Ahern <dsahern@xxxxxxxxx> wrote:
> On 5/3/17 11:02 AM, Cong Wang wrote:
>> A quick glance shows we need to simply check local->rt6i_idev
>> since we do the same check for sprt right above.
>
> As I recall, rt6i_idev is set for all routes except null_entry and it is
> not set on null_entry only because of initialization order.

Are you sure?

        if (event == NETDEV_REGISTER && (dev->flags & IFF_LOOPBACK)) {
                net->ipv6.ip6_null_entry->dst.dev = dev;
                net->ipv6.ip6_null_entry->rt6i_idev = in6_dev_get(dev);
#ifdef CONFIG_IPV6_MULTIPLE_TABLES
                net->ipv6.ip6_prohibit_entry->dst.dev = dev;
                net->ipv6.ip6_prohibit_entry->rt6i_idev = in6_dev_get(dev);
                net->ipv6.ip6_blk_hole_entry->dst.dev = dev;
                net->ipv6.ip6_blk_hole_entry->rt6i_idev = in6_dev_get(dev);
#endif
        }

Loopback is the first one to register, so null entry is set to
loopback dev initially. Similar for init_net.