From: Naoya Horiguchi <[email protected]>
3.12-stable review patch. If anyone has any objections, please let me know.
===============
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 <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: James Hogan <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Andrea Arcangeli <[email protected]>
Cc: Luiz Capitulino <[email protected]>
Cc: Nishanth Aravamudan <[email protected]>
Cc: Lee Schermerhorn <[email protected]>
Cc: Steve Capper <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Jiri Slaby <[email protected]>
---
mm/hugetlb.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 723e63aefb64..33193ab3dbd3 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2517,9 +2517,10 @@ again:
continue;
/*
- * 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);
continue;
}
--
2.3.0
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