From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757448Ab3AOSkw (ORCPT ); Tue, 15 Jan 2013 13:40:52 -0500 Received: from a.painless.aa.net.uk ([81.187.30.51]:40769 "EHLO a.painless.aa.net.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755462Ab3AOSkv (ORCPT ); Tue, 15 Jan 2013 13:40:51 -0500 Date: Tue, 15 Jan 2013 18:40:45 +0000 From: Andrew Clayton To: Rik van Riel Cc: Gleb Natapov , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Ingo Molnar , Jiri Kosina Subject: Re: qemu-kvm hangs at start up under 3.8.0-rc3-00074-gb719f43 (works with CONFIG_LOCKDEP) Message-ID: <20130115184045.574a0fd7@omega.digital-domain.net> In-Reply-To: <20130115171756.36566374@zeus.pccl.info> References: <20130113222958.64840242@omega.digital-domain.net> <20130114132736.GA12489@redhat.com> <20130114182449.5a163101@omega.digital-domain.net> <50F58867.6010507@redhat.com> <20130115171756.36566374@zeus.pccl.info> X-Mailer: Claws Mail 3.9.0 (GTK+ 2.24.8; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 15 Jan 2013 17:17:56 +0000, Andrew Clayton wrote: > On Tue, 15 Jan 2013 11:48:39 -0500, Rik van Riel wrote: > > > On 01/14/2013 01:24 PM, Andrew Clayton wrote: > > [snip] > > > > > > > bash S ffff88013b2b0d00 0 3203 3133 0x00000000 > > > ffff880114dabe58 0000000000000082 8000000113558065 > > > ffff880114dabfd8 ffff880114dabfd8 0000000000004000 > > > ffff88013b0c5b00 ffff88013b2b0d00 ffff880114dabd88 > > > ffffffff8109067d ffffea0004536670 ffffea0004536640 Call Trace: > > > [] ? default_wake_function+0xd/0x10 > > > [] ? atomic_notifier_call_chain+0x15/0x20 > > > [] ? tty_get_pgrp+0x3f/0x50 > > > [] ? pid_vnr+0x2c/0x30 > > > [] ? tty_ioctl+0x7b4/0xbd0 > > > [] ? wait_consider_task+0x102/0xaf0 > > > [] schedule+0x24/0x70 > > > [] do_wait+0x1d4/0x200 > > > [] sys_wait4+0x9b/0xf0 > > > [] ? task_stopped_code+0x50/0x50 > > > [] system_call_fastpath+0x16/0x1b > > > > > > qemu-kvm D ffff88011ab8c8b8 0 3345 3203 0x00000000 > > > ffff880112129cd8 0000000000000082 ffff880112129c50 > > > ffff880112129fd8 ffff880112129fd8 0000000000004000 > > > ffff88013b04ce00 ffff880139da1a00 0000000000000000 > > > 00000000000280da ffff880112129d38 ffffffff810d3300 Call Trace: > > > [] ? __alloc_pages_nodemask+0xf0/0x7c0 > > > [] ? touch_atime+0x66/0x170 > > > [] ? generic_file_aio_read+0x5bf/0x730 > > > [] schedule+0x24/0x70 > > > [] rwsem_down_failed_common+0xbd/0x150 > > > [] rwsem_down_write_failed+0x13/0x15 > > > [] call_rwsem_down_write_failed+0x13/0x20 > > > [] ? down_write+0x2d/0x34 > > > [] vma_adjust+0xe4/0x610 > > > [] vma_merge+0x1b4/0x270 > > > [] do_brk+0x196/0x330 > > > [] sys_brk+0xd7/0x130 > > > [] system_call_fastpath+0x16/0x1b > > > > This looks like qemu-kvm getting stuck trying to get the anon_vma > > lock. > > > > That leads to the obvious question: what is holding the lock, and/or > > failed to release it? > > > > Do you have any other (qemu-kvm?) processes on your system that have > > any code in the VM (or strace/ptrace/...) in the backtrace, that > > might be holding this lock? > > I don't think so. The above was done having just logged into > gnome-shell and opened up a couple of gnome-terminals. > > > Do you have anything in your dmesg showing threads that had a BUG_ON > > (and exited) while holding the lock? > > I never noticed anything like that. > > The interesting thing is that if I use basically the same kernel but > with CONFIG_LOCKDEP enabled, it works fine. > > Hmm, I wonder if it's the same as this? > http://lkml.indiana.edu/hypermail/linux/kernel/1301.1/02810.html > > When I get home, I'll try a kernel with those two patches reverted. > They seem to be > > 572043c90db65b45a4efd959db7458edcf6411ad > 1b963c81b14509e330e0fe3218b645ece2738dc5 Just checked the issue is still there in Linus' latest, 3.8.0-rc3-00293-g406089d, it is. However, building a kernel with those two commits reverted does indeed get it going again. Andrew