From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757594Ab2JAXAX (ORCPT ); Mon, 1 Oct 2012 19:00:23 -0400 Received: from 1wt.eu ([62.212.114.60]:35109 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757494Ab2JAXAO (ORCPT ); Mon, 1 Oct 2012 19:00:14 -0400 Message-Id: <20121001225159.944146084@1wt.eu> User-Agent: quilt/0.48-1 Date: Tue, 02 Oct 2012 00:52:52 +0200 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: "David S. Miller" , Damian Lukowski , Eric Dumazet , Ben Hutchings , Willy Tarreau Subject: [ 055/180] tcp: Dont change unlocked socket state in tcp_v4_err(). In-Reply-To: <6a854f579a99b4fe2efaca1057e8ae22@local> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.32-longterm review patch. If anyone has any objections, please let me know. ------------------ From: David S. Miller commit 8f49c2703b33519aaaccc63f571b465b9d2b3a2d upstream. Alexey Kuznetsov noticed a regression introduced by commit f1ecd5d9e7366609d640ff4040304ea197fbc618 ("Revert Backoff [v3]: Revert RTO on ICMP destination unreachable") The RTO and timer modification code added to tcp_v4_err() doesn't check sock_owned_by_user(), which if true means we don't have exclusive access to the socket and therefore cannot modify it's critical state. Just skip this new code block if sock_owned_by_user() is true and eliminate the now superfluous sock_owned_by_user() code block contained within. Reported-by: Alexey Kuznetsov Signed-off-by: David S. Miller CC: Damian Lukowski Acked-by: Eric Dumazet Cc: Ben Hutchings Signed-off-by: Willy Tarreau --- net/ipv4/tcp_ipv4.c | 8 +++----- 1 files changed, 3 insertions(+), 5 deletions(-) diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 6fc7961..6a4e832 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -406,6 +406,9 @@ void tcp_v4_err(struct sk_buff *icmp_skb, u32 info) !icsk->icsk_backoff) break; + if (sock_owned_by_user(sk)) + break; + icsk->icsk_backoff--; inet_csk(sk)->icsk_rto = __tcp_set_rto(tp) << icsk->icsk_backoff; @@ -420,11 +423,6 @@ void tcp_v4_err(struct sk_buff *icmp_skb, u32 info) if (remaining) { inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, remaining, TCP_RTO_MAX); - } else if (sock_owned_by_user(sk)) { - /* RTO revert clocked out retransmission, - * but socket is locked. Will defer. */ - inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, - HZ/20, TCP_RTO_MAX); } else { /* RTO revert clocked out retransmission. * Will retransmit now */ -- 1.7.2.1.45.g54fbc