Commit ac369918 authored Feb 11, 2015 by Naoya Horiguchi Committed by Sasha Levin Mar 14, 2015

mm/hugetlb: add migration entry check in __unmap_hugepage_range



commit 9fbc1f635fd0bd28cb32550211bf095753ac637a upstream.

If __unmap_hugepage_range() tries to unmap the address range over which
hugepage migration is on the way, we get the wrong page because pte_page()
doesn't work for migration entries.  This patch simply clears the pte for
migration entries as we do for hwpoison entries.

Fixes: 290408d4 ("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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>

parent fa94a396

mm/hugetlb.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -2653,9 +2653,10 @@ again:
		goto unlock;

		/*
		* HWPoisoned hugepage is already unmapped and dropped reference
		* Migrating hugepage or HWPoisoned hugepage is already
		* unmapped and its refcount is dropped, so just clear pte here.
		*/
		if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) {
		if (unlikely(!pte_present(pte))) {
		huge_pte_clear(mm, address, ptep);
		goto unlock;
		}