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authorstephen hemminger <shemminger@vyatta.com>2010-03-03 08:19:59 +0000
committerDavid S. Miller <davem@davemloft.net>2010-03-04 00:39:34 -0800
commit8f37ada5b5f6bfb4d251a7f510f249cb855b77b3 (patch)
tree8f39575febf0319570798117f8738f5127084634 /net
parent84e8b803f1e16f3a2b8b80f80a63fa2f2f8a9be6 (diff)
downloadop-kernel-dev-8f37ada5b5f6bfb4d251a7f510f249cb855b77b3.zip
op-kernel-dev-8f37ada5b5f6bfb4d251a7f510f249cb855b77b3.tar.gz
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>
Diffstat (limited to 'net')
-rw-r--r--net/ipv6/addrconf.c18
1 files changed, 13 insertions, 5 deletions
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 7a4bf76..6cf3ee1 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -2615,7 +2615,7 @@ static void addrconf_bonding_change(struct net_device *dev, unsigned long event)
static int addrconf_ifdown(struct net_device *dev, int how)
{
struct inet6_dev *idev;
- struct inet6_ifaddr *ifa, **bifa;
+ struct inet6_ifaddr *ifa, *keep_list, **bifa;
struct net *net = dev_net(dev);
int i;
@@ -2689,8 +2689,12 @@ static int addrconf_ifdown(struct net_device *dev, int how)
write_lock_bh(&idev->lock);
}
#endif
- bifa = &idev->addr_list;
- while ((ifa = *bifa) != NULL) {
+ keep_list = NULL;
+ bifa = &keep_list;
+ while ((ifa = idev->addr_list) != NULL) {
+ idev->addr_list = ifa->if_next;
+ ifa->if_next = NULL;
+
addrconf_del_timer(ifa);
/* If just doing link down, and address is permanent
@@ -2698,6 +2702,9 @@ static int addrconf_ifdown(struct net_device *dev, int how)
if (how == 0 &&
(ifa->flags&IFA_F_PERMANENT) &&
!(ipv6_addr_type(&ifa->addr) & IPV6_ADDR_LINKLOCAL)) {
+
+ /* Move to holding list */
+ *bifa = ifa;
bifa = &ifa->if_next;
/* If not doing DAD on this address, just keep it. */
@@ -2714,8 +2721,6 @@ static int addrconf_ifdown(struct net_device *dev, int how)
ifa->flags |= IFA_F_TENTATIVE;
in6_ifa_hold(ifa);
} else {
- *bifa = ifa->if_next;
- ifa->if_next = NULL;
ifa->dead = 1;
}
write_unlock_bh(&idev->lock);
@@ -2726,6 +2731,9 @@ static int addrconf_ifdown(struct net_device *dev, int how)
write_lock_bh(&idev->lock);
}
+
+ idev->addr_list = keep_list;
+
write_unlock_bh(&idev->lock);
/* Step 5: Discard multicast list */
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