Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752902Ab0LFMgn (ORCPT ); Mon, 6 Dec 2010 07:36:43 -0500 Received: from fxip-0047f.externet.hu ([88.209.222.127]:55263 "EHLO pomaz-ex.szeredi.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751200Ab0LFMgm (ORCPT ); Mon, 6 Dec 2010 07:36:42 -0500 To: Michael Leun CC: miklos@szeredi.hu, hughd@google.com, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org In-reply-to: <20101203085350.55f94057@xenia.leun.net> (message from Michael Leun on Fri, 3 Dec 2010 08:53:50 +0100) Subject: Re: kernel BUG at mm/truncate.c:475! References: <20101130194945.58962c44@xenia.leun.net> <20101201124528.6809c539@xenia.leun.net> <20101202084159.6bff7355@xenia.leun.net> <20101202091552.4a63f717@xenia.leun.net> <20101202115722.1c00afd5@xenia.leun.net> <20101203085350.55f94057@xenia.leun.net> Message-Id: From: Miklos Szeredi Date: Mon, 06 Dec 2010 13:36:30 +0100 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2094 Lines: 61 On Fri, 3 Dec 2010, Michael Leun wrote: > On Thu, 2 Dec 2010 11:57:22 +0100 > Michael Leun wrote: > > > > Can you please describe in detail the workload that's causing this > > > to happen? > > > > Thats rather complicated, but I'll try. Basically it boils down to: > > > > unshare -n -m /bin/bash > > unionfs -o > > cow,suid,allow_other,max_files=65536 /home/netenv/user1-union=RW:/=RO /home/netenv/user1 > > mount -n -t proc none /home/netenv/user1/proc mount -n -t sysfs > > none /home/netenv/user1/sys mount -n -t devtmpfs > > devtmpfs /home/netenv/user1/dev mount -n -t devpts > > devpts /home/netenv/user1/dev/pts chroot /home/netenv/user1 /bin/su - > > user1 > [...] > > In some of this setups two or more environments share the same > > writable branch, so the files in this environments changed against > > real root of the machine are the same, e.g.: > > > > [...] > > unionfs -o > > cow,suid,allow_other,max_files=65536 /home/netenv/commondir=RW:/=RO /home/netenv/user1 > > [...] > > > > and another one > > > > [...] > > unionfs -o > > cow,suid,allow_other,max_files=65536 /home/netenv/commondir=RW:/=RO /home/netenv/user2 > > [...] > > Additional note: Happens also WITHOUT that "two unionfs mounts use the > same branch dir" stuff. Thanks. For you the workaround would be to use the "kernel_cache" option which disables cache invalidation on open. I'll try to reproduce the BUG on my machine, and if I don't succeed I'll need som more help from you. Also could you please send me your kernel .config > > Really seems to happen much more often in 2.6.36.1 than in 2.6.36. Probably just coincidence. Sometimes the frequency a bug shows up depends on code layout (and hence cache layout) differences, which can vary from compile to compile and even from one boot to the next. Thanks, Miklos -- 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/