From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: System blocks (hangs) on ifconfig up Date: Sun, 12 Dec 2010 21:29:46 +0100 Message-ID: <1292185786.18698.5.camel@edumazet-laptop> References: <4D04E57C.7020509@trego.co.il> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: netdev@vger.kernel.org To: Shmulik Hen Return-path: Received: from mail-ww0-f44.google.com ([74.125.82.44]:42571 "EHLO mail-ww0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754010Ab0LLU3w (ORCPT ); Sun, 12 Dec 2010 15:29:52 -0500 Received: by wwa36 with SMTP id 36so5647921wwa.1 for ; Sun, 12 Dec 2010 12:29:50 -0800 (PST) In-Reply-To: <4D04E57C.7020509@trego.co.il> Sender: netdev-owner@vger.kernel.org List-ID: Le dimanche 12 d=C3=A9cembre 2010 =C3=A0 17:08 +0200, Shmulik Hen a =C3= =A9crit : > Hello, >=20 > My system is Ubuntu 10.04, running kernel 2.6.32-26-generic. >=20 > Whenever I try to bring up a specific ethernet interface for the seco= nd=20 > time, my > system becomes unresponsive for 60 seconds - i.e. no mouse, no keyboa= rd, no > screen refresh. etc. >=20 > Looking at the driver's code, I could see that it's dev->open() metho= d=20 > calls > wait_event_interruptible_timeout() with a timeout of 60 seconds - exa= ctly > the delay I'm seeing. >=20 What is this driver ? > 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 followi= ng > sequence: >=20 > > sudo ifconfig shmulik0 up > > sudo ifconfig shmulik0 down > > sudo ifconfig shmulik0 up >=20 > At this point - the system is stuck for 10 seconds. >=20 Certainly not "stuck for 10 seconds" mdelay(10000) suspends this task for 10 seconds, but other tasks can certainly run. However, your shell waits that "ifconfig ... up" finishes.