From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753139Ab1AXPBO (ORCPT ); Mon, 24 Jan 2011 10:01:14 -0500 Received: from gate.lvk.cs.msu.su ([158.250.17.1]:57654 "EHLO mail.lvk.cs.msu.su" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752906Ab1AXPBM (ORCPT ); Mon, 24 Jan 2011 10:01:12 -0500 X-Spam-ASN: Date: Mon, 24 Jan 2011 18:00:57 +0300 From: Alexander Gordeev To: Linus Torvalds Cc: Ingo Molnar , Andrew Morton , Linux Kernel Mailing List , Thomas Gleixner Subject: Re: PPS parport boot lockup: INFO: HARDIRQ-READ-safe -> HARDIRQ-READ-unsafe lock order detected Message-ID: <20110124180057.4c0e7b49@desktopvm.lvknet> In-Reply-To: References: <20110119083916.GA2166@elte.hu> <20110121174438.7521539f@tornado.gnet> Organization: LVK X-Mailer: Claws Mail 3.7.6 (GTK+ 2.20.1; i486-pc-linux-gnu) Mime-Version: 1.0 Content-Type: multipart/signed; micalg=PGP-SHA256; boundary="Sig_/P_IFKvyjBwb7BLmDhKKdUKQ"; protocol="application/pgp-signature" X-AV-Checked: ClamAV using ClamSMTP Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --Sig_/P_IFKvyjBwb7BLmDhKKdUKQ Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable =D0=92 Fri, 21 Jan 2011 08:37:34 -0800 Linus Torvalds =D0=BF=D0=B8=D1=88=D0=B5=D1= =82: > On Fri, Jan 21, 2011 at 6:44 AM, Alexander Gordeev > wrote: > > > > But parport_unregister_device should probably never be called while > > parport interrupts are enabled (in hardware). So this is a false > > positive. Is this right? >=20 > "Enabled in hardware" is immaterial - with shared interrupts, it > doesn't matter one whit whether parport interrupts are disabled on the > chip, because some other chip may be using the same interrupt line. >=20 > So you'd need to have something that guarantees that there is no > concurrent use, like actually unregistering the irq handler itself. > Things like that can work. >=20 > HOWEVER, even then I think you should see the lockdep message as a > problem. The automated toolchain is great because it shows problems > that it thinks might happen - not when they happen, but based on a > simpler theoretical model. Ignoring the error because there is some > rule in place that is hard to explain to the automated toolchain is > the wrong thing to do, because it makes the lockdep automation less > reliable. >=20 > Think of it as a compiler warning - maybe the warning doesn't actually > imply an actual bug, but you should strive to write code that doesn't > warn, because otherwise the noise from the warning you ignored will > make it harder for others to see the _real_ bugs. >=20 > Linus Ok, thank you very much for clarification! I'll send the patch as reply to the first e-mail. --=20 Alexander --Sig_/P_IFKvyjBwb7BLmDhKKdUKQ Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) iQEcBAEBCAAGBQJNPZQqAAoJEElrwznyooJbA48H/1mScxYuFuuvO7XfXvGbGJL/ 8I6IA19XOK8FhcjKcGHp1C3w/DTgMTe+QzarjFFx1dyRaNO2J76RMX+/ZKEmfZk3 rLZge5yT9VWcp8BY/4ip2KGPr7kBHizYyXWF2ojRNnvChgJsYRuGoVwaIK2GddTb GBG+Kq+qtTv6lqsAKvcmA+MpMDxkzi282tHau60+NlcioqIQDR/8xG6ev8Oxha2O 7Ai2rS5NgtmMHv2zU0x0RmrFNpO8unhUP7U6vrO6YVF8x1Nfnoe41DU7is9fLNeV jx4d7ExZAYPQJxuRYXtC50xvcUPf7IRqIT7fqlin6I3IAV4P8cucD6A9RSoud/8= =XHWN -----END PGP SIGNATURE----- --Sig_/P_IFKvyjBwb7BLmDhKKdUKQ--