IPv6: fix race between cleanup and add/delete address
This solves a potential race problem during the cleanup process. The issue is that addrconf_ifdown() needs to traverse address list, but then drop lock to call the notifier. The version in -next could get confused if add/delete happened during this window. Original code (2.6.32 and earlier) was okay because all addresses were always deleted. Signed-off-by: Stephen Hemminger <shemminger@vyatta.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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@ -2615,7 +2615,7 @@ static void addrconf_bonding_change(struct net_device *dev, unsigned long event)
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static int addrconf_ifdown(struct net_device *dev, int how)
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static int addrconf_ifdown(struct net_device *dev, int how)
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{
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{
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struct inet6_dev *idev;
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struct inet6_dev *idev;
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struct inet6_ifaddr *ifa, **bifa;
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struct inet6_ifaddr *ifa, *keep_list, **bifa;
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struct net *net = dev_net(dev);
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struct net *net = dev_net(dev);
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int i;
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int i;
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@ -2689,8 +2689,12 @@ static int addrconf_ifdown(struct net_device *dev, int how)
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write_lock_bh(&idev->lock);
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write_lock_bh(&idev->lock);
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}
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}
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#endif
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#endif
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bifa = &idev->addr_list;
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keep_list = NULL;
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while ((ifa = *bifa) != NULL) {
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bifa = &keep_list;
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while ((ifa = idev->addr_list) != NULL) {
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idev->addr_list = ifa->if_next;
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ifa->if_next = NULL;
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addrconf_del_timer(ifa);
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addrconf_del_timer(ifa);
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/* If just doing link down, and address is permanent
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/* If just doing link down, and address is permanent
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@ -2698,6 +2702,9 @@ static int addrconf_ifdown(struct net_device *dev, int how)
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if (how == 0 &&
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if (how == 0 &&
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(ifa->flags&IFA_F_PERMANENT) &&
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(ifa->flags&IFA_F_PERMANENT) &&
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!(ipv6_addr_type(&ifa->addr) & IPV6_ADDR_LINKLOCAL)) {
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!(ipv6_addr_type(&ifa->addr) & IPV6_ADDR_LINKLOCAL)) {
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/* Move to holding list */
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*bifa = ifa;
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bifa = &ifa->if_next;
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bifa = &ifa->if_next;
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/* If not doing DAD on this address, just keep it. */
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/* If not doing DAD on this address, just keep it. */
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@ -2714,8 +2721,6 @@ static int addrconf_ifdown(struct net_device *dev, int how)
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ifa->flags |= IFA_F_TENTATIVE;
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ifa->flags |= IFA_F_TENTATIVE;
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in6_ifa_hold(ifa);
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in6_ifa_hold(ifa);
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} else {
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} else {
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*bifa = ifa->if_next;
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ifa->if_next = NULL;
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ifa->dead = 1;
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ifa->dead = 1;
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}
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}
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write_unlock_bh(&idev->lock);
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write_unlock_bh(&idev->lock);
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@ -2726,6 +2731,9 @@ static int addrconf_ifdown(struct net_device *dev, int how)
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write_lock_bh(&idev->lock);
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write_lock_bh(&idev->lock);
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}
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}
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idev->addr_list = keep_list;
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write_unlock_bh(&idev->lock);
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write_unlock_bh(&idev->lock);
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/* Step 5: Discard multicast list */
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/* Step 5: Discard multicast list */
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