I was able to easily reproduce it by running 'make check'. The first
test case (gcore) reliably fails with either a system hang or an MCA.

Bisect shows that it was introduced by the following commit:

62eede62dafb4a6633eae7ffbeb34c60dba5e7b1 is the first bad commit
commit 62eede62dafb4a6633eae7ffbeb34c60dba5e7b1
Author: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Date: Mon Sep 21 17:03:34 2009 -0700

mm: ZERO_PAGE without PTE_SPECIAL

Reinstate anonymous use of ZERO_PAGE to all architectures, not just to
those which __HAVE_ARCH_PTE_SPECIAL: as suggested by Nick Piggin.

Contrary to how I'd imagined it, there's nothing ugly about this, just a
zero_pfn test built into one or another block of vm_normal_page().

But the MIPS ZERO_PAGE-of-many-colours case demands is_zero_pfn() and
my_zero_pfn() inlines. Reinstate its mremap move_pte() shuffling of
ZERO_PAGEs we did from 2.6.17 to 2.6.19? Not unless someone shouts for
that: it would have to take vm_flags to weed out some cases.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Rik van Riel <riel@redhat.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

I also checked SLES11 SP1, but this issue was not reproducible. I went
through the config differences & found that the relevant difference is
PAGE_SIZE. For whatever reason, 64KB pages (which SLES uses) masks the
issue, while 16KB (Debian) does not.




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