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Commit 4c5ff6a6 authored by Herbert Xu's avatar Herbert Xu Committed by David S. Miller
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ipv6: Use state_lock to protect ifa state 



This patch makes use of the new state_lock to synchronise between
updates to the ifa state.  This fixes the issue where a remotely
triggered address deletion (through DAD failure) coincides with a
local administrative address deletion, causing certain actions to
be performed twice incorrectly.

Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e9d3e084

net/ipv6/addrconf.c

+23 −4
Original line number Diff line number Diff line
@@ -715,13 +715,20 @@ static void ipv6_del_addr(struct inet6_ifaddr *ifp) 
{

	struct inet6_ifaddr *ifa, *ifn;

	struct inet6_dev *idev = ifp->idev;

	int state;

	int hash;

	int deleted = 0, onlink = 0;

	unsigned long expires = jiffies;



	hash = ipv6_addr_hash(&ifp->addr);



	spin_lock_bh(&ifp->state_lock);

	state = ifp->state;

	ifp->state = INET6_IFADDR_STATE_DEAD;

	spin_unlock_bh(&ifp->state_lock);



	if (state == INET6_IFADDR_STATE_DEAD)

		goto out;



	spin_lock_bh(&addrconf_hash_lock);

	hlist_del_init_rcu(&ifp->addr_lst);
@@ -819,6 +826,7 @@ static void ipv6_del_addr(struct inet6_ifaddr *ifp) 
		dst_release(&rt->u.dst);

	}



out:

	in6_ifa_put(ifp);

}
@@ -2626,6 +2634,7 @@ static int addrconf_ifdown(struct net_device *dev, int how) 
	struct inet6_dev *idev;

	struct inet6_ifaddr *ifa;

	LIST_HEAD(keep_list);

	int state;



	ASSERT_RTNL();
@@ -2666,7 +2675,6 @@ static int addrconf_ifdown(struct net_device *dev, int how) 
		ifa = list_first_entry(&idev->tempaddr_list,

				       struct inet6_ifaddr, tmp_list);

		list_del(&ifa->tmp_list);

		ifa->state = INET6_IFADDR_STATE_DEAD;

		write_unlock_bh(&idev->lock);

		spin_lock_bh(&ifa->lock);
@@ -2704,23 +2712,34 @@ static int addrconf_ifdown(struct net_device *dev, int how) 


			/* Flag it for later restoration when link comes up */

			ifa->flags |= IFA_F_TENTATIVE;

			in6_ifa_hold(ifa);



			write_unlock_bh(&idev->lock);



			in6_ifa_hold(ifa);

		} else {

			list_del(&ifa->if_list);

			ifa->state = INET6_IFADDR_STATE_DEAD;

			write_unlock_bh(&idev->lock);



			/* clear hash table */

			spin_lock_bh(&addrconf_hash_lock);

			hlist_del_init_rcu(&ifa->addr_lst);

			spin_unlock_bh(&addrconf_hash_lock);



			write_unlock_bh(&idev->lock);

			spin_lock_bh(&ifa->state_lock);

			state = ifa->state;

			ifa->state = INET6_IFADDR_STATE_DEAD;

			spin_unlock_bh(&ifa->state_lock);



			if (state == INET6_IFADDR_STATE_DEAD)

				goto put_ifa;

		}



		__ipv6_ifa_notify(RTM_DELADDR, ifa);

		if (ifa->state == INET6_IFADDR_STATE_DEAD)

			atomic_notifier_call_chain(&inet6addr_chain,

						   NETDEV_DOWN, ifa);



put_ifa:

		in6_ifa_put(ifa);



		write_lock_bh(&idev->lock);