Re: Warning in during hotplug on 2.6.27-rc2-git5

["Rafael J. Wysocki" <rjw@sisk.pl>]

On Thursday, 14 of August 2008, Langsdorf, Mark wrote:
> > On Thu, Aug 14, 2008 at 05:53:57PM +0200, Rafael J. Wysocki wrote:
> > > On Wednesday, 13 of August 2008, Mark Langsdorf wrote:
> > > > I'm seeing the following error message when I hotunplug and replug
> > > > a cpu in 2.6.27-rc2-git5.  The system becomes unstable almost
> > > > immediately afterwards.
> > > 
> > > Hm, it seems that MCE is involved somehow.  Andi, can you 
> > have a look at this,
> > > please?
> > 
> > FWIW the mce code here actually hasn't changed for a long time.
> > 
> > 
> > > > ------------[ cut here ]------------
> > > > WARNING: at fs/sysfs/dir.c:463 sysfs_add_one+0x33/0x39()
> > > > sysfs: duplicate filename 'machinecheck4' can not be created
> > 
> > The only way I could see that happening if CPU_DEAD/CPU_ONLINE
> > is not properly balanced.
> 
> I'm still seeing it on 2.6.27-rc2, even with the 
> patch here http://lkml.org/lkml/2008/7/30/171 and the
> wbinvd_halt code patch applied.  Maybe something else
> broke in some of the recent hotplug changes?

My guess is that MCE does somthing that is not allowed by sysfs any more.

Thanks,
Rafael