Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758666AbYHVJSh (ORCPT ); Fri, 22 Aug 2008 05:18:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752148AbYHVJS3 (ORCPT ); Fri, 22 Aug 2008 05:18:29 -0400 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:44415 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752028AbYHVJS2 (ORCPT ); Fri, 22 Aug 2008 05:18:28 -0400 Date: Fri, 22 Aug 2008 11:18:27 +0200 From: Pavel Machek To: Vegard Nossum Cc: Dmitry Adamushko , Oleg Nesterov , Peter Zijlstra , "Rafael J. Wysocki" , Max Krasnyanskiy , Linux Kernel Mailing List Subject: Re: latest -git: hibernate: possible circular locking dependency detected Message-ID: <20080822091827.GC6542@atrey.karlin.mff.cuni.cz> References: <19f34abd0808210804y7ee91d1fy12da5ad6f82d2451@mail.gmail.com> <19f34abd0808211059m451f5f7au949217aeecccccaf@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <19f34abd0808211059m451f5f7au949217aeecccccaf@mail.gmail.com> User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2134 Lines: 57 Hi! > > this path is triggered as a result of "echo disk > /sys/power/state" > > Yes. That is what I typed. > > > > > disable_nonboot_cpus() calls cpu_maps_update_being() which takes > > "cpu_add_remove_lock" (lock-1). > > > > If we go down the road cleanup_workqueue_thread() -> > > flush_cpu_workqueue() will take "cwq->lock" (lock-2). > > So this should be the second lock. > > > > > [...] > > > hmm, did you somehow hit "Sysrq + o"? > > > > 'cause I don't see any other places (say, with handle_sysrq(k,...) > > where "k" migth be 'o') from where do_power_off() might have been > > triggered... > > > > No. But in my logs I often saw SysRq triggered, even though I didn't > do it any of these times: > > log-20080821-104053.txt:SysRq : SysRq : Show State > log-20080821-105541.txt:SysRq : Emergency Sync > log-20080821-105541.txt:SysRq : Emergency Sync > log-20080821-105541.txt:SysRq : Power Off > log-20080821-110514.txt:SysRq : Terminate All Tasks > log-20080821-111650.txt:SysRq : HELP : loglevel0-8 <6>serial 00:0d: activated > log-20080821-111650.txt:SysRq : Power Off > log-20080821-111650.txt:SysRq : Terminate All Tasks > log-20080821-111650.txt:SysRq : SysRq : <6>serial 00:0d: activated > log-20080821-120628.txt:SysRq : SysRq : HELP : HELP : <6>serial 00:0d: activated > log-20080821-120628.txt:SysRq : SysRq : HELP : HELP : <6>serial 00:0d: activated > > (And it seems to pick a random letter too. It even showed the "HELP:" > line at one point!) > > I have no idea why this happens. Is it possible to trigger SysRq by > writing data on the other end of the serial console? (Maybe my cable > is bad or something, but data seems to be going in both directions > over my serial console.) Serial break translates to sysrq, IIRC. -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- 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/