Re: [GIT PULL] SLAB changes for v2.6.39-rc1

[Pekka Enberg]

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Hi Ingo,

On Thu, 24 Mar 2011, Ingo Molnar wrote:
> * Pekka Enberg <penberg@xxxxxxxxxx> wrote:
>
> > On Thu, Mar 24, 2011 at 4:41 PM, Christoph Lameter <cl@xxxxxxxxx> wrote:
> > > On Thu, 24 Mar 2011, Ingo Molnar wrote:
> > >
> > > > FYI, some sort of boot crash has snuck upstream in the last 24 hours:
> > > >
> > > >  BUG: unable to handle kernel paging request at ffff87ffc147e020
> > > >  IP: [<ffffffff811aa762>] this_cpu_cmpxchg16b_emu+0x2/0x1c
> > >
> > > Hmmm.. This is the fallback code for the case that the processor does not
> > > support cmpxchg16b.
> >
> > How does alternative_io() work? Does it require
> > alternative_instructions() to be executed. If so, the fallback code
> > won't be active when we enter kmem_cache_init(). Is there any reason
> > check_bugs() is called so late during boot? Can we do something like
> > the totally untested attached patch?
>
> Does the config i sent you boot on your box? I think the bug is pretty generic
> and should trigger on any box.

Here's a patch that reorganizes the alternatives fixup to happen earlier 
so that the fallback should work. It boots on my machine so please give it 
a spin if possible.

I'll try out your .config next.

			Pekka