Commit 176c39af authored by Daniel Lezcano's avatar Daniel Lezcano Committed by David S. Miller
Browse files

netns: fix addrconf_ifdown kernel panic 



When a network namespace is destroyed the network interfaces are
all unregistered, making addrconf_ifdown called by the netdevice
notifier. 
In the other hand, the addrconf exit method does a loop on the network
devices and does addrconf_ifdown on each of them. But the ordering of 
the netns subsystem is not right because it uses the register_pernet_device
instead of register_pernet_subsys. If we handle the loopback as
any network device, we can safely use register_pernet_subsys.

But if we use register_pernet_subsys, the addrconf exit method will do
exactly what was already done with the unregistering of the network
devices. So in definitive, this code is pointless.

I removed the netns addrconf exit method and moved the code to the
addrconf cleanup function.

Signed-off-by: default avatarDaniel Lezcano <dlezcano@fr.ibm.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent b325fddb

net/ipv6/addrconf.c

+9 −30
Original line number Diff line number Diff line
@@ -2611,9 +2611,6 @@ static int addrconf_ifdown(struct net_device *dev, int how) 


	ASSERT_RTNL();



	if ((dev->flags & IFF_LOOPBACK) && how == 1)

		how = 0;



	rt6_ifdown(net, dev);

	neigh_ifdown(&nd_tbl, dev);
@@ -4448,25 +4445,6 @@ int unregister_inet6addr_notifier(struct notifier_block *nb) 


EXPORT_SYMBOL(unregister_inet6addr_notifier);



static void addrconf_net_exit(struct net *net)

{

	struct net_device *dev;



	rtnl_lock();

	/* clean dev list */

	for_each_netdev(net, dev) {

		if (__in6_dev_get(dev) == NULL)

			continue;

		addrconf_ifdown(dev, 1);

	}

	addrconf_ifdown(net->loopback_dev, 2);

	rtnl_unlock();

}



static struct pernet_operations addrconf_net_ops = {

	.exit = addrconf_net_exit,

};



/*

 *	Init / cleanup code

 */
@@ -4508,10 +4486,6 @@ int __init addrconf_init(void) 
	if (err)

		goto errlo;



	err = register_pernet_device(&addrconf_net_ops);

	if (err)

		return err;



	register_netdevice_notifier(&ipv6_dev_notf);



	addrconf_verify(0);
@@ -4541,15 +4515,22 @@ errlo: 
void addrconf_cleanup(void)

{

	struct inet6_ifaddr *ifa;

	struct net_device *dev;

	int i;



	unregister_netdevice_notifier(&ipv6_dev_notf);

	unregister_pernet_device(&addrconf_net_ops);



	unregister_pernet_subsys(&addrconf_ops);



	rtnl_lock();



	/* clean dev list */

	for_each_netdev(&init_net, dev) {

		if (__in6_dev_get(dev) == NULL)

			continue;

		addrconf_ifdown(dev, 1);

	}

	addrconf_ifdown(init_net.loopback_dev, 2);



	/*

	 *	Check hash table.

	 */
@@ -4570,6 +4551,4 @@ void addrconf_cleanup(void) 


	del_timer(&addr_chk_timer);

	rtnl_unlock();



	unregister_pernet_subsys(&addrconf_net_ops);

}

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