[PATCH RT 1/4] tcp: force a dst refcount when prequeue packet

[Steven Rostedt <rostedt@goodmis.org>]

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From: Eric Dumazet <edumazet@google.com>

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

Cc: stable-rt@vger.kernel.org
Reported-by: Mike Galbraith <bitbucket@online.de>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 include/net/tcp.h |    1 +
 1 file changed, 1 insertion(+)

diff --git a/include/net/tcp.h b/include/net/tcp.h
index b28a49f..4881cb6 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -902,6 +902,7 @@ static inline int tcp_prequeue(struct sock *sk, struct sk_buff *skb)
 	if (sysctl_tcp_low_latency || !tp->ucopy.task)
 		return 0;
 
+	skb_dst_force(skb);
 	__skb_queue_tail(&tp->ucopy.prequeue, skb);
 	tp->ucopy.memory += skb->truesize;
 	if (tp->ucopy.memory > sk->sk_rcvbuf) {
-- 
1.7.10.4