Subject: Re: [vserver] Concurrency issue in /proc?
From: Herbert Poetzl <herbert@13thfloor.at>
Date: Tue, 6 Jul 2010 02:54:51 +0200

On Mon, Jul 05, 2010 at 02:10:47PM -0400, Patrick LeBoutillier wrote:
> Hi,

> I tried with util-vserver and I can't reproduce the problem 
> either on an 8 core server.

> However I noticed that Jacque's tools mount /proc once 
> for each vserver:

> none on /vservers/v1/proc type proc (rw)
> none on /vservers/v2/proc type proc (rw)
> none on /vservers/v3/proc type proc (rw)

there is no point in doing that ...

> However with util-vserver from the root server I don't 
> see extra mounts for /proc.

because /proc, like other guest specific filesystems
are mounted inside the guest filesystem namespace

> How is /proc made visible inside the guest?

as normal mount, inside the guest namespace ...

you might want to double check that Jacque's tools
are up-to-date as security might be at risk with
recent kernels if the proper namespace isolation
is not working ...

(which could explain the issues you have encountered)

best,
Herbert

> Patrick

> On Fri, Jul 2, 2010 at 6:17 AM, Oliver Heinz <oheinz@fbihome.de> wrote:
> > Am Donnerstag, 1. Juli 2010 18:33:38 schrieb Patrick LeBoutillier:
> > ...
> >> > I tried here (to recreate the issue) with a dual core
> >> > cpu (kernel 2.6.33.x) but couldn't reproduce ....
> >>
> >> I ran this kernel for months on dual cores with no problems that I
> >> noticed. But since I migrated a few servers to 8 cores (2 quads) I
> >> started experiencing this problem. I don't know if any other vserver
> >> users have access to similar hardware.
> >
> > I just tried to reproduce on an Dual Intel  Xeon X5550 Quadcore CPU System.
> >
> > No errors here.
> >
> > Kernel: 2.6.32.10-grsec2.1.14-vs2.3.0.36.29.2
> > Vserver-utils: 0.30.216~r2844
> >
> >
> > Bye,
> > Oliver
> >
> 
> 
> 
> -- 
> =====================
> Patrick LeBoutillier
> Rosemère, Québec, Canada