3.14-stable review patch. If anyone has any objections, please let me know.
------------------
From: Naoya Horiguchi <n-horigu...@ah.jp.nec.com>
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 <n-horigu...@ah.jp.nec.com>
Cc: Hugh Dickins <hu...@google.com>
Cc: James Hogan <james.ho...@imgtec.com>
Cc: David Rientjes <rient...@google.com>
Cc: Mel Gorman <m...@csn.ul.ie>
Cc: Johannes Weiner <han...@cmpxchg.org>
Cc: Michal Hocko <mho...@suse.cz>
Cc: Rik van Riel <r...@redhat.com>
Cc: Andrea Arcangeli <aarca...@redhat.com>
Cc: Luiz Capitulino <lcapitul...@redhat.com>
Cc: Nishanth Aravamudan <n...@linux.vnet.ibm.com>
Cc: Lee Schermerhorn <lee.schermerh...@hp.com>
Cc: Steve Capper <steve.cap...@linaro.org>
Signed-off-by: Andrew Morton <a...@linux-foundation.org>
Signed-off-by: Linus Torvalds <torva...@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
mm/hugetlb.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2488,9 +2488,10 @@ 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;
}
--
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