From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail143.messagelabs.com (mail143.messagelabs.com [216.82.254.35]) by kanga.kvack.org (Postfix) with SMTP id 8BA1A6B0088 for ; Fri, 3 Dec 2010 02:54:18 -0500 (EST) Date: Fri, 3 Dec 2010 08:53:50 +0100 From: Michael Leun Subject: Re: kernel BUG at mm/truncate.c:475! Message-ID: <20101203085350.55f94057@xenia.leun.net> In-Reply-To: <20101202115722.1c00afd5@xenia.leun.net> 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> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Miklos Szeredi Cc: hughd@google.com, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: 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. Really seems to happen much more often in 2.6.36.1 than in 2.6.36. > I observed that unionfs process takes much more cpu power than usual > before fault happens. This also happens without that "two unionfs mounts use the same branch dir" stuff. -- MfG, Michael Leun -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: email@kvack.org