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

[Greg KH <greg@kroah.com>]

On Sat, Aug 16, 2008 at 09:28:24PM +0200, Rafael J. Wysocki wrote:
> 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.

Hm, sysfs hasn't changed any in 2.6.27-rcX that I know of.

thanks,

greg k-h