From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755566AbZETHNs (ORCPT ); Wed, 20 May 2009 03:13:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752220AbZETHNj (ORCPT ); Wed, 20 May 2009 03:13:39 -0400 Received: from xc.sipsolutions.net ([83.246.72.84]:60683 "EHLO sipsolutions.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752319AbZETHNj (ORCPT ); Wed, 20 May 2009 03:13:39 -0400 Subject: Re: INFO: possible circular locking dependency at cleanup_workqueue_thread From: Johannes Berg To: Ming Lei Cc: Oleg Nesterov , Ingo Molnar , Zdenek Kabelac , "Rafael J. Wysocki" , Peter Zijlstra , Linux Kernel Mailing List In-Reply-To: References: <20090517071834.GA8507@elte.hu> <1242559101.28127.63.camel@johannes.local> <20090518194749.GA3501@redhat.com> <1242723104.17164.5.camel@johannes.local> <20090519120010.GA14782@redhat.com> <1242747203.4797.39.camel@johannes.local> <1242802064.31350.12.camel@johannes.local> Content-Type: multipart/signed; micalg="pgp-sha1"; protocol="application/pgp-signature"; boundary="=-H2xL3S1i8JXU6Zb77J29" Date: Wed, 20 May 2009 09:12:49 +0200 Message-Id: <1242803569.31350.14.camel@johannes.local> Mime-Version: 1.0 X-Mailer: Evolution 2.26.1.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --=-H2xL3S1i8JXU6Zb77J29 Content-Type: text/plain Content-Transfer-Encoding: quoted-printable On Wed, 2009-05-20 at 15:09 +0800, Ming Lei wrote: > 2009/5/20 Johannes Berg : > > On Wed, 2009-05-20 at 11:36 +0800, Ming Lei wrote: > > > >> > Anyway, you can have a deadlock like this: > >> > > >> > CPU 3 CPU 2 CPU 1 > >> > suspend/hiber= nate > >> > something: > >> > rtnl_lock() device_pm_loc= k() > >> > -> mutex_lock= (&dpm_list_mtx) > >> > > >> > mutex_lock(&dpm_list_mtx) > >> > >> Would you give a explaination why mutex_lock(&dpm_list_mtx) runs in CP= U2 > >> and depends on rtnl_lock? > > > > Why not? Something is registering a hotplugged netdev. >=20 > I see. I just feel a bit curious how lockdep may build the dependency > of dpm_list_mtx on rtnl_lock, and it is certainly related with > lockdep internal. No, it's just the way drivers/base/power/ works -- it acquires the lock when you register a new struct device. johannes --=-H2xL3S1i8JXU6Zb77J29 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- iQIcBAABAgAGBQJKE61tAAoJEODzc/N7+QmacHoP/3CFnvxLsuGIwC8EUGnkatAG g27m4dBxba/GewrUD97q6GZ6rb8DDwmf7El5ZZlJOWigttvB3mez+NF1PLfvM4vl DbWkLv34tncxoyFf/ToFEwYsYXlhJx5vKFKPoArsbARGGlKAtaT+REE/RWHT3rhT HmeXBH18XrWU1aen9an6y05ZEr48QSUfJJtzS2g58WBSJ1uNmD51Z4JJ8c1pl211 0ToRvzeDwDIvkxI4HvbxsIXmj0QPUvM6pGbMe1sYHnOLIOKSRMqikeMtK1G9Z2pa 1hjmSUxeqNuGaU0Z622fVqBmciAh+py5IIkkPfNglBNcZaCvLMrXzlEGWi7x4Ydt uvgg06N7vDwqm4A95TPnGgbfnw9kdjHHN98GNbJYkLxDosEaXhGJl/+d4vFGkzAj Mqz1g6JbxERPVqh5tHQ2IgVDsABYgm04HFnIpE6vOUEfivblKXgl+BI9A7K70tLj xJqJOlEDymg+UsAmifSiQEtS1aaez/zHVGnGI+oTYw0orx0HBUjtCtY4wmn+BJ4o 9qy2jgoDs3oAhwfEBlQXFBIRp6jjSYppfjpsLAh9yLU6syv46Ald1Wn4HOEkNuva IFJUDLp/NvwWPEjtu+isXAoely/QEWGqfAatBg2nTGpt/7OnyrAQ4Jg3uePwo1GD IaUHJQ2rISiwJn/5aMXC =Kp9l -----END PGP SIGNATURE----- --=-H2xL3S1i8JXU6Zb77J29--