Re: net/ipv6: GPF in rt6_device_match

From: Cong Wang
Date: Wed May 03 2017 - 18:03:18 EST

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-> = dev;
net->ipv6.ip6_null_entry->rt6i_idev = in6_dev_get(dev);
net->ipv6.ip6_prohibit_entry-> = dev;
net->ipv6.ip6_prohibit_entry->rt6i_idev = in6_dev_get(dev);
net->ipv6.ip6_blk_hole_entry-> = dev;
net->ipv6.ip6_blk_hole_entry->rt6i_idev = in6_dev_get(dev);

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