[ 15/33] tcp: force a dst refcount when prequeue packet

From: Greg Kroah-Hartman
Date: Fri May 17 2013 - 17:52:38 EST


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

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


From: Eric Dumazet <edumazet@xxxxxxxxxx>

[ Upstream commit 093162553c33e9479283e107b4431378271c735d ]

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

Reported-by: Mike Galbraith <bitbucket@xxxxxxxxx>
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
include/net/tcp.h | 1 +
1 file changed, 1 insertion(+)

--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -902,6 +902,7 @@ static inline int tcp_prequeue(struct so
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) {


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