From mboxrd@z Thu Jan 1 00:00:00 1970 From: Erwan Velu Subject: Remarks and comments about ipconfig behavior Date: Thu, 13 Sep 2012 22:21:15 +0200 Message-ID: <5052403B.4040408@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit To: netdev@vger.kernel.org Return-path: Received: from mail-ey0-f174.google.com ([209.85.215.174]:32791 "EHLO mail-ey0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756092Ab2IMUVY (ORCPT ); Thu, 13 Sep 2012 16:21:24 -0400 Received: by eaac11 with SMTP id c11so1435764eaa.19 for ; Thu, 13 Sep 2012 13:21:22 -0700 (PDT) Sender: netdev-owner@vger.kernel.org List-ID: Hey Fellows ! I've been figuring a strange behavior today and I'd like to share with you both experience and remarks. On my system that runs a 3.2.29 but that's also applicable with linux-next and all other releases. As shown here : http://git.kernel.org/?p=linux/kernel/git/next/linux-next.git;a=blob;f=net/ipv4/ipconfig.c;h=67e8a6b086ea7a0d2c4cc986ed6ed0e6b4414c6a;hb=HEAD#l262 , if you specify an ip= option on the cmdline, the kernel is expecting the carrier to be present unless it will make a loop up to 2mn as per CONF_CARRIER_TIMEOUT value. That lever for me two points : - why is this timeout setup for so long ? Even with a spantree configuration, not having a carrier for 2mn is *waow* ... Does a 30sec could not be enough ? What is the need of waiting so long time ? - Until we get the carrier, the kernel just stops and the boot process is totally locked but there isn't any message shown to the user. The system really look like frozen/dead for 2 minutes. I spent a complete day trying to understand why my box was unable to boot while the network cable was removed. I just discover this behavior by comparing log files to understand that was the reason. So my suggestion would be the following and I can offer patches if you agree on thoses points : - reducing the timeout to something smaller like 30sec - display a message every second to inform the user we are waiting the carrier to satisfy the ipconfig option What are you thoughts on that ? Thanks you, Erwan Velu