Re: [BUG] 2.6.23-git8 kernel oops at __rb_rotate_left+0x7/0x70

[Andy Whitcroft <apw@shadowen.org>]

On Tue, Oct 16, 2007 at 07:00:37PM +0100, Andy Whitcroft wrote:
> On Tue, Oct 16, 2007 at 11:46:31AM +0200, Ingo Molnar wrote:
> > 
> > * Ingo Molnar <mingo@elte.hu> wrote:
> > 
> > > 
> > > * Kamalesh Babulal <kamalesh@linux.vnet.ibm.com> wrote:
> > > 
> > > > While running kernbench with the 2.6.23-git8 following oops is 
> > > > produced
> > > > 
> > > > Unable to handle kernel NULL pointer dereference at 0000000000000010 RIP: 
> > > >  [<ffffffff8033f347>] __rb_rotate_left+0x7/0x70
> > > 
> > > that looks nasty ...
> > > 
> > > and -git8 should have the v2.6.23 scheduler code in essence.
> > 
> > ah, this is likely with the recent scheduler commits included as well, 
> > right?
> > 
> > if it's reproducable, could you try with group scheduling disabled, i.e. 
> > with:
> > 
> >   # CONFIG_FAIR_GROUP_SCHED is not set
> > 
> > as that would be the main suspect for such type of a crash.
> 
> Ok, preliminary results with this disabled seem to get us past
> kernbench.  I am rerunning with it enabled to confirm it blammo's.

A rerun with it enabled however ran to completion.  So I think we have
to assume this is at best not 100% reproducible.  Seems that more
directed testing is going on now.

-apw