netdev - [PATCH net] tcp: fastopen: avoid negative sk_forward

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Date:   Wed, 07 Sep 2016 08:34:11 -0700
From:   Eric Dumazet <eric.dumazet@...il.com>
To:     David Miller <davem@...emloft.net>
Cc:     netdev <netdev@...r.kernel.org>, Josh Hunt <johunt@...mai.com>,
        Jerry Chu <hkchu@...gle.com>,
        Yuchung Cheng <ycheng@...gle.com>,
        Neal Cardwell <ncardwell@...gle.com>
Subject: [PATCH net] tcp: fastopen: avoid negative sk_forward_alloc

From: Eric Dumazet <edumazet@...gle.com>

When DATA and/or FIN are carried in a SYN/ACK message or SYN message,
we append an skb in socket receive queue, but we forget to call
sk_forced_mem_schedule().

Effect is that the socket has a negative sk->sk_forward_alloc as long as
the message is not read by the application.

Josh Hunt fixed a similar issue in commit d22e15371811 ("tcp: fix tcp
fin memory accounting")
 
Fixes: 168a8f58059a ("tcp: TCP Fast Open Server - main code path")
Signed-off-by: Eric Dumazet <edumazet@...gle.com>
---
 net/ipv4/tcp_fastopen.c |    1 +
 1 file changed, 1 insertion(+)

diff --git a/net/ipv4/tcp_fastopen.c b/net/ipv4/tcp_fastopen.c
index 62a5751d4fe1..4e777a3243f9 100644
--- a/net/ipv4/tcp_fastopen.c
+++ b/net/ipv4/tcp_fastopen.c
@@ -150,6 +150,7 @@ void tcp_fastopen_add_skb(struct sock *sk, struct sk_buff *skb)
 	tp->segs_in = 0;
 	tcp_segs_in(tp, skb);
 	__skb_pull(skb, tcp_hdrlen(skb));
+	sk_forced_mem_schedule(sk, skb->truesize);
 	skb_set_owner_r(skb, sk);
 
 	TCP_SKB_CB(skb)->seq++;