mm/hugetlb: add migration/hwpoisoned entry check in hugetlb_change_protection
authorNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Wed, 11 Feb 2015 23:25:28 +0000 (15:25 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Thu, 12 Feb 2015 01:06:01 +0000 (17:06 -0800)
commita8bda28d87c38c6aa93de28ba5d30cc18e865a11
tree1c9f477663c6dd1f0caded7d633cbaf8e43fa377
parent0f792cf949a0be506c2aa8bfac0605746b146dda
mm/hugetlb: add migration/hwpoisoned entry check in hugetlb_change_protection

There is a race condition between hugepage migration and
change_protection(), where hugetlb_change_protection() doesn't care about
migration entries and wrongly overwrites them.  That causes unexpected
results like kernel crash.  HWPoison entries also can cause the same
problem.

This patch adds is_hugetlb_entry_(migration|hwpoisoned) check in this
function to do proper actions.

Fixes: 290408d4a2 ("hugetlb: hugepage migration core")
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: <stable@vger.kernel.org> [2.6.36+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/hugetlb.c