Bug#588574: bisect results

[dann frazier <dannf@debian.org>]

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.