From 29d0a309d11bac9e57af914d0d6a35cde0080861 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= <ilpo.jarvinen@helsinki.fi>
Date: Sun, 7 Oct 2007 23:36:41 -0700
Subject: [PATCH] [TCP]: Fix two off-by-one errors in fackets_out adjusting
logic
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1) Passing wrong skb to tcp_adjust_fackets_out could corrupt
fastpath_cnt_hint as tcp_skb_pcount(next_skb) is not included
to it if hint points exactly to the next_skb (it's lagging
behind, see sacktag).
2) When fastpath_skb_hint is put backwards to avoid dangling
skb reference, the skb's pcount must also be removed from count
(not included like above).
Reported by Cedric Le Goater <legoater@free.fr>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/ipv4/tcp_output.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 6199abeb0f5e..53296753b0bd 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -1755,14 +1755,16 @@ static void tcp_retrans_try_collapse(struct sock *sk, struct sk_buff *skb, int m
if (tcp_is_reno(tp) && tp->sacked_out)
tcp_dec_pcount_approx(&tp->sacked_out, next_skb);
- tcp_adjust_fackets_out(tp, skb, tcp_skb_pcount(next_skb));
+ tcp_adjust_fackets_out(tp, next_skb, tcp_skb_pcount(next_skb));
tp->packets_out -= tcp_skb_pcount(next_skb);
/* changed transmit queue under us so clear hints */
tcp_clear_retrans_hints_partial(tp);
/* manually tune sacktag skb hint */
- if (tp->fastpath_skb_hint == next_skb)
+ if (tp->fastpath_skb_hint == next_skb) {
tp->fastpath_skb_hint = skb;
+ tp->fastpath_cnt_hint -= tcp_skb_pcount(skb);
+ }
sk_stream_free_skb(sk, next_skb);
}
--
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