This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
Home Products Support Community News


Re: [Xen-devel] domU oom -> xvda1 read-only without any notice?

To: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Subject: Re: [Xen-devel] domU oom -> xvda1 read-only without any notice?
From: Ian Campbell <Ian.Campbell@xxxxxxxxxx>
Date: Wed, 31 Mar 2010 09:54:59 +0100
Cc: "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>, Josip Rodin <joy@xxxxxxxxxxxxxx>
Delivery-date: Wed, 31 Mar 2010 01:55:33 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <C7D8CA1D.F509%keir.fraser@xxxxxxxxxxxxx>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
Organization: Citrix Systems, Inc.
References: <C7D8CA1D.F509%keir.fraser@xxxxxxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
On Wed, 2010-03-31 at 09:45 +0100, Keir Fraser wrote:
> AFAIK that means that the read-only-ness is not being propagated up to
> domU block layer by the xen_blockfront driver. I'm not sure exactly
> what other possibilities there are, but if the kernel has been OOMing
> processes then perhaps you're in a runlevel or mode, or even a kenrel
> bug, in which rootfs is forced read-only for other reasons? There have
> been bugs around OOM in the past, and really it's a kernel path that's
> obviously best avoided! Any idea why the OOM occurred in the first
> place?

Root filesystems are often mounted with the "errors=remount-ro" option
(is it the Debian default?). So it's possible this is a domU decision to
go read-only, but the question remains as to what happened in the domU
to trigger this decision, can an OOM do that? There might be something
earlier in the domU dmesg?


Xen-devel mailing list