Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756548AbYHHMox (ORCPT ); Fri, 8 Aug 2008 08:44:53 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752191AbYHHMoo (ORCPT ); Fri, 8 Aug 2008 08:44:44 -0400 Received: from py-out-1112.google.com ([64.233.166.182]:10166 "EHLO py-out-1112.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752031AbYHHMon (ORCPT ); Fri, 8 Aug 2008 08:44:43 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=Ki7rTIcB6Vj0zqLyZis5ut9OjGusLxlaJvZ5/q07djz5Xy61yn8dDFMemFyMbor3Ia 7L7RxUXyMuS3fKn9jGm0vFBUEOCCMY1CAIpKvyDvvcnYmFN2LrJEYZQx4R29ynIONv9l thZ2GO9EmEYVc03pQUkjYAl2jUFsLUJAia8g0= Date: Fri, 8 Aug 2008 08:44:33 -0400 From: Dmitry Torokhov To: Peter Zijlstra Cc: Andrew Morton , Zdenek Kabelac , linux-kernel@vger.kernel.org, linux-input@vger.kernel.org, Jiri Kosina , Rabin Vincent Subject: Re: INFO: possible recursive locking detected ps2_command Message-ID: <20080808082930.ZZRA012@mailhub.coreip.homeip.net> References: <20080731145739.fe8923be.akpm@linux-foundation.org> <20080801030444.GB18953@anvil.corenet.prv> <1218192589.8625.88.camel@twins> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1218192589.8625.88.camel@twins> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2461 Lines: 69 On Fri, Aug 08, 2008 at 12:49:49PM +0200, Peter Zijlstra wrote: > On Thu, 2008-07-31 at 23:04 -0400, Dmitry Torokhov wrote: > > On Thu, Jul 31, 2008 at 02:57:39PM -0700, Andrew Morton wrote: > > > > > > (cc linux-input) > > > > > > On Thu, 31 Jul 2008 11:41:25 +0200 > > > "Zdenek Kabelac" wrote: > > > > > > > Hi > > > > > > > > During mouse unplugging from psaux connector from the laptops' docking > > > > station I've got attached INFO trace. > > > > (laptops still has synaptics device) > > > > > > > > Dell? > > > > > > Also for unknown reason to me psaux mouse & synaptic device do not > > > > work somehow together - is it hw limitation > > > > of /dev/input/mice interface? > > > > (USB mouse and synaptics do work quite well together) > > > > > > > > [ INFO: possible recursive locking detected ] > > > > 2.6.27-rc1 #48 > > > > > > (it's 2.6.27-rc1) > > > > > > > Peter, here is the trace we talked about long time ago. For some reason > > lockdep annotation only works once. If reconnect is forced or psmouse > > module is reloaded lockdep starts complaining about passthrough port. > > Bit puzzling - and I don't have any ps2 hardware around to test with > (nor do I normally use modules - but that is fixable of course). > > Does Rabin's patch help? > > http://lkml.org/lkml/2008/8/7/329 > I doubt it resolves problem fully because it only takes care of module unload. I can easily trip lockdep by reconnecting the device. Just to give some more details about the problem: - synaptics touchpads have a pass-through port that allows to connect either external mouse or maybe a trackpoint device. Both devices are represented by 'serio' structures and are handled by the same driver (psmouse). - as far as I know we have proper locking there and lockdep annotatinos were added to lockdep to reflect the nesting of the serio ports. - if child port (pass-through port) is destroyed and recreated (due to module unload, or because user requested reconnect through sysfs or system-initiated reconnect) lockdep starts complaining although the new child port should still have the same "depth" as the old one. Thanks! -- Dmitry -- 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/