From: Ilpo Järvinen Date: Mon, 8 Oct 2007 06:36:41 +0000 (-0700) Subject: [TCP]: Fix two off-by-one errors in fackets_out adjusting logic X-Git-Tag: v2.6.24-rc1~1454^2~148 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=29d0a309d11bac9e57af914d0d6a35cde0080861;p=linux-2.6 [TCP]: Fix two off-by-one errors in fackets_out adjusting logic 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 --- diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 6199abeb0f..53296753b0 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); }