From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Hutchings Subject: Re: System blocks (hangs) on ifconfig up Date: Sun, 12 Dec 2010 23:03:03 +0000 Message-ID: <1292194983.3136.294.camel@localhost> References: <4D04E38A.1040605@trego.co.il> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org To: Shmulik Hen Return-path: Received: from exchange.solarflare.com ([216.237.3.220]:37917 "EHLO exchange.solarflare.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751351Ab0LLXDH (ORCPT ); Sun, 12 Dec 2010 18:03:07 -0500 In-Reply-To: <4D04E38A.1040605@trego.co.il> Sender: netdev-owner@vger.kernel.org List-ID: On Sun, 2010-12-12 at 17:00 +0200, Shmulik Hen wrote: > Hello, > > My system is Ubuntu 10.04, running kernel 2.6.32-26-generic. > > Whenever I try to bring up a specific ethernet interface for the second > time, my > system becomes unresponsive for 60 seconds - i.e. no mouse, no keyboard, no > screen refresh. etc. > > Looking at the driver's code, I could see that it's dev->open() method calls > wait_event_interruptible_timeout() with a timeout of 60 seconds - exactly > the delay I'm seeing. That seems like a stupid thing for it to do. > I have narrowed the code to a bare minimum (see below - loosely based on > dummy.c), which only calls mdelay(10000) in it's dev->open() method, and > still, my system blocks for exactly 10 seconds when I run the following > sequence: > > > sudo ifconfig shmulik0 up > > sudo ifconfig shmulik0 down > > sudo ifconfig shmulik0 up > > At this point - the system is stuck for 10 seconds. Bringing an interface up or down is a synchronous operation and is serialised with most other network configuration operations. So this is the expected behaviour. Ben. -- Ben Hutchings, Senior Software Engineer, Solarflare Communications Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked.