From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752676AbaKCBJz (ORCPT ); Sun, 2 Nov 2014 20:09:55 -0500 Received: from szxga02-in.huawei.com ([119.145.14.65]:61792 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751250AbaKCBJx (ORCPT ); Sun, 2 Nov 2014 20:09:53 -0500 Message-ID: <5456D5C7.9040104@huawei.com> Date: Mon, 3 Nov 2014 09:09:27 +0800 From: chenweilong User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:24.0) Gecko/20100101 Thunderbird/24.5.0 MIME-Version: 1.0 To: David Miller CC: , , , , Subject: Re: [PATCH] ipv4: avoid divide 0 error in tcp_incr_quickack References: <1414767047-8972-1-git-send-email-chenweilong@huawei.com> <20141101.170605.1353817217163030327.davem@davemloft.net> In-Reply-To: <20141101.170605.1353817217163030327.davem@davemloft.net> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.37.162] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Sure, Thanks On 2014/11/2 5:06, David Miller wrote: > From: Chen Weilong > Date: Fri, 31 Oct 2014 22:50:47 +0800 > >> From: Weilong Chen >> >> We got a problem like this: >> [ffff8801c1a05570] machine_kexec at ffffffff81025039 >> [ffff8801c1a055d0] crash_kexec at ffffffff8109b253 >> [ffff8801c1a056a0] oops_end at ffffffff81442aed >> [ffff8801c1a056d0] die at ffffffff81005603 >> [ffff8801c1a05700] do_trap at ffffffff81442448 >> [ffff8801c1a05760] do_divide_error at ffffffff81002c10 >> [ffff8801c1a05888] tcp_send_dupack at ffffffff81385e44 >> [ffff8801c1a058c8] tcp_validate_incoming at ffffffff813886b5 >> [ffff8801c1a05908] tcp_rcv_state_process at ffffffff8138d0b7 >> [ffff8801c1a05958] tcp_child_process at ffffffff81397255 >> [ffff8801c1a05988] tcp_v4_do_rcv at ffffffff81395a70 >> [ffff8801c1a059d8] tcp_v4_rcv at ffffffff81396fc8 >> [ffff8801c1a05a48] ip_local_deliver_finish at ffffffff813746e9 >> [ffff8801c1a05a78] ip_local_deliver at ffffffff81374a20 >> [ffff8801c1a05aa8] ip_rcv_finish at ffffffff81374389 >> [ffff8801c1a05ad8] ip_rcv at ffffffff81374c78 >> There was a wrong ack packet coming during TCP handshake. The socket's state >> was TCP_SYN_RECV, its rcv_mss was not initialize yet. So >> tcp_send_dupack -> tcp_enter_quickack_mode got a divide 0 error. >> This patch add a state check before tcp_enter_quickack_mode. >> >> Signed-off-by: Weilong Chen > > Can you please resubmit this, properly CC:'ing netdev@vger.kernel.org this > time? > > Thank you. > > . >