ipv6: Do not depend on rt->n in rt6_check_neigh().

CC: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 2839381116ea574a1faf95d71954797074718bfc..c7bcd777db230e8e46e2804eac1453353f8bd2a3 100644 (file)
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -546,20 +546,24 @@ static inline bool rt6_check_neigh(struct rt6_info *rt)
        struct neighbour *neigh;
        bool ret = false;
 
-       neigh = rt->n;
        if (rt->rt6i_flags & RTF_NONEXTHOP ||
            !(rt->rt6i_flags & RTF_GATEWAY))
-               ret = true;
-       else if (neigh) {
-               read_lock_bh(&neigh->lock);
+               return true;
+
+       rcu_read_lock_bh();
+       neigh = __ipv6_neigh_lookup_noref(rt->dst.dev, &rt->rt6i_gateway);
+       if (neigh) {
+               read_lock(&neigh->lock);
                if (neigh->nud_state & NUD_VALID)
                        ret = true;
 #ifdef CONFIG_IPV6_ROUTER_PREF
                else if (!(neigh->nud_state & NUD_FAILED))
                        ret = true;
 #endif
-               read_unlock_bh(&neigh->lock);
+               read_unlock(&neigh->lock);
        }
+       rcu_read_unlock_bh();
+
        return ret;
 }