[PATCH 085/115] tcp: force a dst refcount when prequeue packet

[Luis Henriques]

3.5.7.13 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Eric Dumazet <edumazet at google.com>

commit 093162553c33e9479283e107b4431378271c735d upstream.

Before escaping RCU protected section and adding packet into
prequeue, make sure the dst is refcounted.

Reported-by: Mike Galbraith <bitbucket at online.de>
Signed-off-by: Eric Dumazet <edumazet at google.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
[ luis: adjust context ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 include/net/tcp.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 851f8fa..4857dce 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -982,6 +982,7 @@ static inline bool tcp_prequeue(struct sock *sk, struct sk_buff *skb)
 	if (sysctl_tcp_low_latency || !tp->ucopy.task)
 		return false;
 
+	skb_dst_force(skb);
 	__skb_queue_tail(&tp->ucopy.prequeue, skb);
 	tp->ucopy.memory += skb->truesize;
 	if (tp->ucopy.memory > sk->sk_rcvbuf) {
-- 
1.8.1.2