From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jarek Poplawski Subject: Re: [PATCH] vlan: lockdep subclass for ppp _xmit_lock Re: ppp_generic: fix lockdep warning Date: Thu, 10 May 2007 07:30:52 +0200 Message-ID: <20070510053052.GA1611@ff.dom.local> References: <200704260727.l3Q7RTxG023970@shell0.pdx.osdl.net> <20070426.013911.69219176.davem@davemloft.net> <20070426104950.GA3145@ff.dom.local> <20070509093536.GA2436@ff.dom.local> <001801c79275$80cd5e00$0701010a@note> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: akpm@linux-foundation.org, netdev@vger.kernel.org, paulus@samba.org, greearb@candelatech.com, mostrows@speakeasy.net, davem@davemloft.net To: "Yuriy N\. Shkandybin" Return-path: Received: from mx12.go2.pl ([193.17.41.142]:57752 "EHLO poczta.o2.pl" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755328AbXEJFYa (ORCPT ); Thu, 10 May 2007 01:24:30 -0400 Content-Disposition: inline In-Reply-To: <001801c79275$80cd5e00$0701010a@note> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Thu, May 10, 2007 at 12:06:09AM +0400, Yuriy N. Shkandybin wrote: > After applying this patch i've got this: > > ======================================================= > [ INFO: possible circular locking dependency detected ] > 2.6.21-gentoo #2 > ------------------------------------------------------- > ospfd/3984 is trying to acquire lock: > (&ppp->wlock){-...}, at: [] ppp_xmit_process+0x20/0x4f0 > > but task is already holding lock: > (&dev->_xmit_lock){-+..}, at: [] __qdisc_run+0x88/0x1c3 > > which lock already depends on the new lock. Thanks Yuriy! As a matter of fact I suspected there will be something more. Lockdep always stops working after the first warning, and you have some very interesting (entangled) configuration, so each fix could uncover new warnings. I need some time to figure out this one, so I'd try to use your help yet... I hope it's only about lockdep warnings and there are no real lockups. Best regards, Jarek P.