neigh: check error pointer instead of NULL for ipv4_neigh_lookup()

Fixes: commit f187bc6efb7250afee0e2009b6106 ("ipv4: No need to set generic neighbour pointer")
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 173e7ea..cbadb94 100644 (file)
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -746,7 +746,7 @@ static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flow
        }
 
        n = ipv4_neigh_lookup(&rt->dst, NULL, &new_gw);
-       if (n) {
+       if (!IS_ERR(n)) {
                if (!(n->nud_state & NUD_VALID)) {
                        neigh_event_send(n, NULL);
                } else {