Messages in this thread | | | From | Neil Brown <> | Date | Sun, 1 Apr 2007 07:46:47 +1000 | Subject | Re: 2.6.21-rc5-mm[12]: Oops on bootup in xor_see_2 |
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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.
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