Re: [PATCH] slub: Disable the lockless allocator

[Ingo Molnar]

* Christoph Lameter <cl@xxxxxxxxx> wrote:

> On Sat, 26 Mar 2011, Christoph Lameter wrote:
> 
> > Tejun: Whats going on there? I should be getting offsets into the per cpu
> > area and not kernel addresses.
> 
> Its a UP kernel running on dual Athlon. So its okay ... Argh.... The
> following patch fixes it by using the fallback code for cmpxchg_double:
> 
> 
> 
> Subject: per_cpu: Fixup cmpxchg_double for !SMP
> 
> cmpxchg_double should only be provided for SMP. In the UP case
> the GS register is not defined and the function will fail.
> 
> Signed-off-by: Christoph Lameter <cl@xxxxxxxxx>

I.e. the bug got introduced by:

 | commit b9ec40af0e18fb7d02106be148036c2ea490fdf9
 | Author: Christoph Lameter <cl@xxxxxxxxx>
 | Date:   Mon Feb 28 11:02:24 2011 +0100
 |
 |     percpu, x86: Add arch-specific this_cpu_cmpxchg_double() support

and then the lockless allocator made use of it, right?

Thanks,

	Ingo
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