tcp: Fix queue traversal in tcp_use_frto().

We must check tcp_skb_is_last() before doing a tcp_write_queue_next().

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 0 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index cbfe13d5f423..3b76bce769dd 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1746,6 +1746,8 @@ int tcp_use_frto(struct sock *sk)
                 return 0;
 
         skb = tcp_write_queue_head(sk);
+        if (tcp_skb_is_last(sk, skb))
+                return 1;
         skb = tcp_write_queue_next(sk, skb);    /* Skips head */
         tcp_for_write_queue_from(skb, sk) {
                 if (skb == tcp_send_head(sk))