Subject: Re: Strange events leading to "Hotplug scripts not working" and xen death
To: Avleen Vig <>
From: Manuel Bouyer <>
List: port-xen
Date: 05/15/2007 19:34:19
On Tue, May 15, 2007 at 08:49:27AM -0700, Avleen Vig wrote:
> I apologise to anyone who is on xen-users or xen-devel. I posted this to
> both lists and was told I should talk to the netbsd xen maintainers :-)
> Can anyone here help me with this? I really odn't want to have to use
> Linux for my Dom0, but I might be forced to at this rate :-(
> I think it's a bug in whatever is supposed to execute the vif-bridge
> script (but I'm not sure if that is xend, or xenbackend).

It's xenbackend

> System: NetBSD 4.0 BETA2 as of ~1 week ago, Xen 3 compiled from pkgsrc.

Is it xen-3.0.3 or xen-3.0.4 ?

> I have Dom0 working just fine. It boots without a problem.
> I also have a file-backed Linux DomU which starts. The config for this
> is at the end.
> I've found a rather.. strange series of events that causes Xen to stop
> creating new DomUs. Even my working Linux DomUs fail to create.
> The thing that makes this strange, is that there doesn't seem to be one
> single thing thing in particular that causes this. For instance,
> following the instructions here on creating a FreeBSD DomU work the
> first time, and after that everything stops working:
> Also, downloading CentOS 5 from causes everything to stop
> working. The configs I used for FreeBSD and CentOS5 are at the end also.
> When things "stop working", I see messages like this when trying to
> create a domain:
>   [root@xen1] /xen/configs # xm create -c freebsd1
>   Using config file "./freebsd1".
>   Error: Device 0 (vif) could not be connected. Hotplug scripts not working.
> Some digging indicated that the scripts (eg,
> /usr/pkg/etc/xen/scripts/vif-bridge) are not actually being accessed any
> more - their access time does not change again until I reboot to fix
> this problem. Restarting xend or any other xen daemons doesn't work.
> *Finally* :-) commands like 'xenstore-ls' just hang too.
> The xenstore commands seem to be hanging trying to read from the store.

So it's most probably an issue with the store. Could you try ktrace to
see on what xenstore-ls hangs ? Is xenstored still running ?
You could try to ktrace it too.

Manuel Bouyer <>
     NetBSD: 26 ans d'experience feront toujours la difference