Re: [BUG] 2.6.6-rc2-bk5 mm/slab.c change broke x86-64 SMP

["R. J. Wysocki" <rjwysocki@sisk.pl>]

On Friday 30 of April 2004 20:27, Andrew Morton wrote:
> Mikael Pettersson <mikpe@csd.uu.se> wrote:
> > The change to mm/slab.c between 2.6.6-rc2-bk4 and -bk5
> > broke x86-64 SMP. The symptoms are general protection
> > faults in __switch_to shortly after init starts, and
> > then the machine is dead. (Can't be more specific, my
> > box can't log early boot oopses.)
> >
> > I'm only seeing this with x86-64 SMP; x86-64 UP and i386
> > SMP on the same machine (Athlon64 UP) have no problems.
> >
> > Reverting 2.6.6-rc2-bk5's change to mm/slab.c eliminates
> > the problem.
>
> The "-bk5" terminology doesn't mean much to people who use bitkeeper or who
> use http://www.kernel.org/pub/linux/kernel/v2.5/testing/cset/ - I assume
> you refer to the alignment changes?
>
> Does this fix?
>
> diff -puN include/asm-x86_64/processor.h~a include/asm-x86_64/processor.h
> --- 25/include/asm-x86_64/processor.h~a	Fri Apr 30 11:24:58 2004
> +++ 25-akpm/include/asm-x86_64/processor.h	Fri Apr 30 11:25:28 2004
> @@ -20,6 +20,8 @@
>  #include <asm/mmsegment.h>
>  #include <linux/personality.h>
>
> +#define ARCH_MIN_TASKALIGN L1_CACHE_BYTES
> +
>  #define TF_MASK		0x00000100
>  #define IF_MASK		0x00000200
>  #define IOPL_MASK	0x00003000
>

AFAICS, yes, it does. :-)
I'm now (happily) running 2.6.6-rc3 on a dual-Opteron box.

RJW