From 29d0a309d11bac9e57af914d0d6a35cde0080861 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Ilpo=20J=C3=A4rvinen?= Date: Sun, 7 Oct 2007 23:36:41 -0700 Subject: [PATCH] [TCP]: Fix two off-by-one errors in fackets_out adjusting logic MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 Signed-off-by: Ilpo Järvinen Signed-off-by: David S. Miller --- 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); } -- 2.20.1