Code: static int __init ipip_init(void)
{
	int err;
 
 	printk(banner);
 
	if (xfrm4_tunnel_register(&ipip_handler, AF_INET)) {
 		printk(KERN_INFO "ipip init: can't register tunnel\n");
		return -EAGAIN;
 	}
	err = register_pernet_device(&ipip_net_ops);
	if (err)
		xfrm4_tunnel_deregister(&ipip_handler, AF_INET);
 	return err;
 }

Vulnerability Type: DoS 
CWE ID: CWE-362
Summary: The tunnels implementation in the Linux kernel before 2.6.34, when tunnel functionality is configured as a module, allows remote attackers to cause a denial of service (OOPS) by sending a packet during module loading.
Commit Message: tunnels: fix netns vs proto registration ordering

Same stuff as in ip_gre patch: receive hook can be called before netns
setup is done, oopsing in net_generic().

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>