lkml.org 
[lkml]   [2007]   [Mar]   [31]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: 2.6.21-rc5-mm[12]: Oops on bootup in xor_see_2
On Saturday March 31, akpm@linux-foundation.org wrote:
> On Sat, 31 Mar 2007 17:36:47 +0000 Bernhard Rosenkraenzer <bero@arklinux.org> wrote:
>
> > I'm getting this Oops when booting an 2.6.21-rc5-mm1 or 2.6.21-rc5-mm2 on an
> > Acer Aspire 1501 LMi in 32 bit mode (2.6.21-rc4-mm1 + hotfixes works
> > perfectly):
> >
> > xor: automatically using best checksumming function: pIII_sse

Hmmm... I've seen that before

> > Code: 44 89 74 24 48 0f 20 c6 0f 06 0f 11 04 24 0f 11 4c 24 10 0f 11 54 24 20
> > 0f
> > 11 5c 24 30 0f 18 82 00 01 00 00 0f 18 82 20 01 00 00 <00> 00 00 00 00
> > 00
> > 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> > -

Them bytes that look like '00' are mostly supposed to look like 'F0' -
an x86 'noop'.

Apparently a bin-utils bug. An alpha of OpenSUSE-10.3 was compiling
kernels like this. I'm told it has been fixed.

What distro/gcc version/binutils version was this compiled on?

It is possible that we should change the ".align 32" in
include/asm-i386/xor.h to ".align 32, 0xf0" or similar, but my
assembler knowledge stopped growing when it reached 6809, so I'd
rather someone who knew something about it did anything that was
required....

>
> Dan, I'm assuming your changes in there are the cause of this. AFAICT all
> you're doing is moving code around, so it's a bit odd.
>
> Bernhard, the config would be useful please.
>
> Neil, is calibrate_xor_block() being rational?
>
> b1 = (void *) __get_free_pages(GFP_KERNEL, 2);
> ...
> b2 = b1 + 2*PAGE_SIZE + BENCH_SIZE;
>
> Is it correct to add BENCH_SIZE to b2 here?

I think it is intentional. I cannot say if it is correct.
The purpose is to defeat cache effects somehow.
The result of that code together with the value of BENCH_SIZE being
PAGE_SIZE is that 4 pages are allocated, and the first and last are
used.
I have no idea how any cache would treat this, but that seems to be
the intent of the code.

NeilBrown
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-03-31 23:49    [W:0.151 / U:0.032 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site