From 2a4edc62b38380cd464fc4b65524f626bf76fb1f Mon Sep 17 00:00:00 2001 From: Naoya Horiguchi Date: Wed, 11 Feb 2015 15:25:32 -0800 Subject: [PATCH] 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: 290408d4a2 ("hugetlb: hugepage migration core") Signed-off-by: Naoya Horiguchi Cc: Hugh Dickins Cc: James Hogan Cc: David Rientjes Cc: Mel Gorman Cc: Johannes Weiner Cc: Michal Hocko Cc: Rik van Riel Cc: Andrea Arcangeli Cc: Luiz Capitulino Cc: Nishanth Aravamudan Cc: Lee Schermerhorn Cc: Steve Capper Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds [lizf: Backported to 3.4: - adjust context - update the comment that we doesn't clear pte here] Signed-off-by: Zefan Li --- mm/hugetlb.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 5f12dba6d08ee..bc36e280ce8bd 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -2401,9 +2401,10 @@ void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, continue; /* - * HWPoisoned hugepage is already unmapped and dropped reference + * Migrating hugepage or HWPoisoned hugepage is already + * unmapped and its refcount is dropped */ - if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) + if (unlikely(!pte_present(pte))) continue; page = pte_page(pte); -- 2.47.2