From patchwork Thu Nov 15 14:03:17 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrei Vagin X-Patchwork-Id: 199293 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id CC6132C03E8 for ; Fri, 16 Nov 2012 01:05:03 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1767895Ab2KOOFB (ORCPT ); Thu, 15 Nov 2012 09:05:01 -0500 Received: from mailhub.sw.ru ([195.214.232.25]:18985 "EHLO relay.sw.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1767889Ab2KOOFA (ORCPT ); Thu, 15 Nov 2012 09:05:00 -0500 Received: from localhost.sw.ru ([10.30.16.61]) by relay.sw.ru (8.13.4/8.13.4) with ESMTP id qAFE3Vrc032117; Thu, 15 Nov 2012 18:03:32 +0400 (MSK) From: Andrey Vagin To: netdev@vger.kernel.org Cc: criu@openvz.org, linux-kernel@vger.kernel.org, Andrew Vagin , Pavel Emelyanov , "David S. Miller" , Alexey Kuznetsov , James Morris , Hideaki YOSHIFUJI , Patrick McHardy Subject: [PATCH] tcp: fix retransmission in repair mode Date: Thu, 15 Nov 2012 18:03:17 +0400 Message-Id: <1352988197-14414-1-git-send-email-avagin@openvz.org> X-Mailer: git-send-email 1.7.11.7 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Andrew Vagin Currently if a socket was repaired with a few packet in a write queue, a kernel bug may be triggered: kernel BUG at net/ipv4/tcp_output.c:2330! RIP: 0010:[] tcp_retransmit_skb+0x5ff/0x610 According to the initial realization v3.4-rc2-963-gc0e88ff, all skb-s should look like already posted. This patch fixes code according with this sentence. Here are three points, which were not done in the initial patch: 1. A tcp send head should not be changed 2. Initialize TSO state of a skb 3. Reset the retransmission time This patch moves logic from tcp_sendmsg to tcp_write_xmit. A packet passes the ussual way, but isn't sent to network. This patch solves all described problems and handles tcp_sendpages. Cc: Pavel Emelyanov Cc: "David S. Miller" Cc: Alexey Kuznetsov Cc: James Morris Cc: Hideaki YOSHIFUJI Cc: Patrick McHardy Signed-off-by: Andrey Vagin Acked-by: Pavel Emelyanov --- net/ipv4/tcp.c | 4 ++-- net/ipv4/tcp_output.c | 4 ++++ 2 files changed, 6 insertions(+), 2 deletions(-) diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 197c000..083092e 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -1212,7 +1212,7 @@ new_segment: wait_for_sndbuf: set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); wait_for_memory: - if (copied && likely(!tp->repair)) + if (copied) tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH); if ((err = sk_stream_wait_memory(sk, &timeo)) != 0) @@ -1223,7 +1223,7 @@ wait_for_memory: } out: - if (copied && likely(!tp->repair)) + if (copied) tcp_push(sk, flags, mss_now, tp->nonagle); release_sock(sk); return copied + copied_syn; diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index cfe6ffe..2798706 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -1986,6 +1986,9 @@ static bool tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle, tso_segs = tcp_init_tso_segs(sk, skb, mss_now); BUG_ON(!tso_segs); + if (unlikely(tp->repair) && tp->repair_queue == TCP_SEND_QUEUE) + goto repair; /* Skip network transmission */ + cwnd_quota = tcp_cwnd_test(tp, skb); if (!cwnd_quota) break; @@ -2026,6 +2029,7 @@ static bool tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle, if (unlikely(tcp_transmit_skb(sk, skb, 1, gfp))) break; +repair: /* Advance the send_head. This one is sent out. * This call will increment packets_out. */