Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966949AbWKVK5N (ORCPT ); Wed, 22 Nov 2006 05:57:13 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S967105AbWKVK5N (ORCPT ); Wed, 22 Nov 2006 05:57:13 -0500 Received: from brick.kernel.dk ([62.242.22.158]:19543 "EHLO kernel.dk") by vger.kernel.org with ESMTP id S966949AbWKVK5M (ORCPT ); Wed, 22 Nov 2006 05:57:12 -0500 Date: Wed, 22 Nov 2006 11:57:03 +0100 From: Jens Axboe To: Jesper Juhl Cc: Linus Torvalds , Linux Kernel Mailing List , Andrew Morton Subject: Re: Simple script that locks up my box with recent kernels Message-ID: <20061122105703.GZ8055@kernel.dk> References: <9a8748490610081633k7bf011d1q131b2f9e06f2808d@mail.gmail.com> <9a8748490610161545i309c416aja4f39edef8ea04e2@mail.gmail.com> <9a8748490610161613y7c314e64rfdfafb4046a33a02@mail.gmail.com> <9a8748490610231330y65f3e243pe1101d11a28dbbfa@mail.gmail.com> <9a8748490611211646o2c92564dmfe8d6ffdf66228ba@mail.gmail.com> <20061122080312.GL8055@kernel.dk> <9a8748490611220255v53bc667y74b05e2b69281f25@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9a8748490611220255v53bc667y74b05e2b69281f25@mail.gmail.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1338 Lines: 32 On Wed, Nov 22 2006, Jesper Juhl wrote: > On 22/11/06, Jens Axboe wrote: > >On Tue, Nov 21 2006, Linus Torvalds wrote: > >> I don't think we use any irq-disable locking in the VM itself, but I > >could > >> imagine some nasty situation with the block device layer getting into a > >> deadlock with interrupts disabled when it runs out of queue entries and > >> cannot allocate more memory.. > > > >Not likely. Request allocation is done with GFP_NOIO and backed by a > >memory pool, so as long the vm doesn't go totally nuts because > >__GFP_WAIT is set, we should be safe there. If it did go crazy, I > >suspect a sysrq-t would still work. > > > >If bouncing is involved for swap, we do have a potential deadlock issue > >that isn't fixed yet. I just whipped up this completely untested patch, > >it should shed some light on that issue. > > > Thanks Jens, I'll apply that later tonight and force a few lockups and > see if I get any extra details with that patch. Can you post a full dmesg too, as well as clarify which device holds the swap space? -- Jens Axboe - 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/