From: Naoya Horiguchi <n-horigu...@ah.jp.nec.com>
3.4.108-rc1 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 <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>
[lizf: Backported to 3.4:
- adjust context
- update the comment that we doesn't clear pte here]
Signed-off-by: Zefan Li <lize...@huawei.com>
---
mm/hugetlb.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 5f12dba..bc36e28 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);
--
1.9.1
--
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