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>

1 files changed, 9 insertions, 5 deletions

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 2839381116ea..c7bcd777db23 100644
--- 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;
 }