Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754978AbaGHNCz (ORCPT ); Tue, 8 Jul 2014 09:02:55 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:40185 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754556AbaGHNCy (ORCPT ); Tue, 8 Jul 2014 09:02:54 -0400 Date: Tue, 8 Jul 2014 15:02:39 +0200 From: Peter Zijlstra To: Mike Galbraith Cc: Jan Kara , Sasha Levin , Peter Hurley , pmladek@suse.cz, Andrew Morton , Jet Chen , LKML , Linus Torvalds Subject: Re: console: lockup on boot Message-ID: <20140708130239.GF6758@twins.programming.kicks-ass.net> References: <53888E76.5040101@hurleysoftware.com> <20140530140757.GC2419@quack.suse.cz> <53921116.5050804@oracle.com> <53972B5C.5020605@hurleysoftware.com> <53986DFB.9030006@oracle.com> <20140611203436.GD9511@quack.suse.cz> <20140611213111.GE9511@quack.suse.cz> <53991958.4070106@oracle.com> <20140612082645.GF9511@quack.suse.cz> <1402563262.5171.2.camel@marge.simpson.net> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="+f314sPv49h+UVDy" Content-Disposition: inline In-Reply-To: <1402563262.5171.2.camel@marge.simpson.net> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --+f314sPv49h+UVDy Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Jun 12, 2014 at 10:54:22AM +0200, Mike Galbraith wrote: > On Thu, 2014-06-12 at 10:26 +0200, Jan Kara wrote:=20 > > On Wed 11-06-14 23:07:04, Sasha Levin wrote: >=20 > > > The first patch fixed it (I assumed that there's no need to try the s= econd). > > Good. So that shows that it is the increased lockdep coverage which is > > causing problems - with my patch, lockdep is able to identify some prob= lem > > because console drivers are now called with lockdep enabled. But because > > the problem was found in some difficult context, lockdep just hung the > > machine when trying to report it... Sadly the stacktraces you posted do= n't > > tell us what lockdep found. > >=20 > > Adding Peter Zijlstra to CC. Peter, any idea how lockdep could report > > problems when holding logbuf_lock? One possibility would be to extend > > logbuf_cpu recursion logic to every holder of logbuf_lock. That will at > > least avoid the spinlock recursion killing the machine but we won't be = able > > to see what lockdep found... >=20 > Could tell lockdep to use trace_printk(). lkml.kernel.org/r/20111221111143.401184003@chello.nl --+f314sPv49h+UVDy Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQIcBAEBAgAGBQJTu+vvAAoJEHZH4aRLwOS6s1oP/0L+erAv/iO6E+Cr/bx7phEQ hjTh2jxEeZbbRYsC76YhKZk/OUv8L6pCrU3LuHMcvdleiu5ie0CGhC0RGdZsYtqE cJM9UOXne6jiqWFDN72noAJe7HL6Pq9RZ8mQbhh/heVTu7s50f3cJb5iq6F1ioVU ulISl5fJ6y8gimwcljqRBsnqIH1R4G54vFRkEzXFmFi4gsyFFJI3EW13IPAJyOL2 Ffdz1qYHPwjYfL0WPa+I8ZBD0ZGy7UpoIlMAx8B107qjH8/E0ITioUyAAenWW+3F 2xA3cFiWZ3/bZ3gOxGy4HI67HErddJPxQIpxEWhtcibnZRrlbqrNQyuuSWrzGsAf YlysRa82RzJCKMKZ0mQ3ZUsh8s/1IgWqLJQVhZ6Sx/e16fwVLou5/cTkKctvLmZ6 uXoaPzFNXzmiHYGWlKQHS3dVtR7h5Iqg1Zsn5vAc7KnpUp6iA1oQIWUcKQ6OJKeD N/RHc2vsBPlytV6wSaOrEn67hO+50tgNXlj6YFpvfJ8lqINOWHdyfTPmJ+r38yiy gJQiRB2nt+Nc3Ot7K7pnVCuvKOsbdtF+Yy2R+NXtdeoYyCxLS06F50sAF/fqjoiC c/Rr5BEDwGBlJ4Kf7DJ2zVVZecaxGspy2eC05htZovV0HqTnmFJ1coJf/wUEyQT5 +WJUj/FaL+wzCzZfbGrQ =T22Z -----END PGP SIGNATURE----- --+f314sPv49h+UVDy-- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/