ip: fix error handling in ip_finish_output2()

__neigh_create() returns either a pointer to struct neighbour or PTR_ERR().
But the caller expects it to return either a pointer or NULL.  Replace
the NULL check with IS_ERR() check.

The bug was introduced in a263b3093641fb1ec377582c90986a7fd0625184
("ipv4: Make neigh lookups directly in output packet path.").

Signed-off-by: Vasily Kulikov <segoon@openwall.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 1 deletions

diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index ba39a52d18c1..76dde25fb9a0 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -197,7 +197,7 @@ static inline int ip_finish_output2(struct sk_buff *skb)
         neigh = __ipv4_neigh_lookup_noref(dev, nexthop);
         if (unlikely(!neigh))
                 neigh = __neigh_create(&arp_tbl, &nexthop, dev, false);
-        if (neigh) {
+        if (!IS_ERR(neigh)) {
                 int res = dst_neigh_output(dst, neigh, skb);
 
                 rcu_read_unlock_bh();