Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932212Ab0KLVf6 (ORCPT ); Fri, 12 Nov 2010 16:35:58 -0500 Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:50259 "EHLO sunset.davemloft.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752733Ab0KLVf4 (ORCPT ); Fri, 12 Nov 2010 16:35:56 -0500 Date: Fri, 12 Nov 2010 13:36:20 -0800 (PST) Message-Id: <20101112.133620.241452814.davem@davemloft.net> To: eric.dumazet@gmail.com Cc: kuznet@ms2.inr.ac.ru, kaber@trash.net, equinox@diac24.net, eparis@redhat.com, hzhong@gmail.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, pekkas@netcore.fi, jmorris@namei.org, yoshfuji@linux-ipv6.org, paul.moore@hp.com, damian@tvk.rwth-aachen.de Subject: Re: a problem tcp_v4_err() From: David Miller In-Reply-To: <1289596718.2743.2.camel@edumazet-laptop> References: <1289586803.3185.275.camel@edumazet-laptop> <20101112.112224.112610807.davem@davemloft.net> <1289596718.2743.2.camel@edumazet-laptop> X-Mailer: Mew version 6.3 on Emacs 23.1 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2284 Lines: 66 From: Eric Dumazet Date: Fri, 12 Nov 2010 22:18:38 +0100 > Acked-by: Eric Dumazet Thanks for reviewing, here is the final bit I committed and I'll queue this up for whatever -stable trees need this. -------------------- tcp: Don't change unlocked socket state in tcp_v4_err(). 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 --- 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 8f8527d..69ccbc1 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -415,6 +415,9 @@ 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; @@ -429,11 +432,6 @@ 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 */ -- 1.7.3.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/