[IPV6]: Fix refcounting for anycast dst entries.

Anycast DST entries allocated inside ipv6_dev_ac_inc are leaked when
network device is stopped without removing IPv6 addresses from it. The
bug has been observed in the reality on 2.6.18-rhel5 kernel.

In the above case addrconf_ifdown marks all entries as obsolete and
ip6_del_rt called from __ipv6_dev_ac_dec returns ENOENT. The
referrence is not dropped.

The fix is simple. DST entry should not keep referrence when stored in
the FIB6 tree.

Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 7 deletions

diff --git a/net/ipv6/anycast.c b/net/ipv6/anycast.c
index 9c7f83fbc3a1..e5f56c953b58 100644
--- a/net/ipv6/anycast.c
+++ b/net/ipv6/anycast.c
@@ -334,9 +334,7 @@ int ipv6_dev_ac_inc(struct net_device *dev, struct in6_addr *addr)
         idev->ac_list = aca;
         write_unlock_bh(&idev->lock);
 
-        dst_hold(&rt->u.dst);
-        if (ip6_ins_rt(rt))
-                dst_release(&rt->u.dst);
+        ip6_ins_rt(rt);
 
         addrconf_join_solict(dev, &aca->aca_addr);
 
@@ -378,10 +376,7 @@ int __ipv6_dev_ac_dec(struct inet6_dev *idev, struct in6_addr *addr)
         addrconf_leave_solict(idev, &aca->aca_addr);
 
         dst_hold(&aca->aca_rt->u.dst);
-        if (ip6_del_rt(aca->aca_rt))
-                dst_free(&aca->aca_rt->u.dst);
-        else
-                dst_release(&aca->aca_rt->u.dst);
+        ip6_del_rt(aca->aca_rt);
 
         aca_put(aca);
         return 0;