[to-be-updated] mm-hugetlb-add-migration-entry-check-in-hugetlb_change_protection.patch removed from -mm tree

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The patch titled
     Subject: mm/hugetlb: add migration entry check in hugetlb_change_protection
has been removed from the -mm tree.  Its filename was
     mm-hugetlb-add-migration-entry-check-in-hugetlb_change_protection.patch

This patch was dropped because an updated version will be merged

------------------------------------------------------
From: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Subject: mm/hugetlb: add migration entry check in hugetlb_change_protection

There is a race condition between hugepage migration and
change_protection(), where hugetlb_change_protection() doesn't care about
migration entries and wrongly overwrites them.  That causes unexpected
results like kernel crash.

This patch adds is_hugetlb_entry_(migration|hwpoisoned) check in this
function and skip all such entries.

Signed-off-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Mel Gorman <mel@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>	[3.12+]
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---

 mm/hugetlb.c |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff -puN mm/hugetlb.c~mm-hugetlb-add-migration-entry-check-in-hugetlb_change_protection mm/hugetlb.c
--- a/mm/hugetlb.c~mm-hugetlb-add-migration-entry-check-in-hugetlb_change_protection
+++ a/mm/hugetlb.c
@@ -3358,7 +3358,13 @@ unsigned long hugetlb_change_protection(
 			spin_unlock(ptl);
 			continue;
 		}
-		if (!huge_pte_none(huge_ptep_get(ptep))) {
+		pte = huge_ptep_get(ptep);
+		if (unlikely(is_hugetlb_entry_migration(pte) ||
+			     is_hugetlb_entry_hwpoisoned(pte))) {
+			spin_unlock(ptl);
+			continue;
+		}
+		if (!huge_pte_none(pte)) {
 			pte = huge_ptep_get_and_clear(mm, address, ptep);
 			pte = pte_mkhuge(huge_pte_modify(pte, newprot));
 			pte = arch_make_huge_pte(pte, vma, NULL, 0);
_

Patches currently in -mm which might be from n-horiguchi@xxxxxxxxxxxxx are

origin.patch
memory-hotplug-add-sysfs-zones_online_to-attribute.patch
mm-hugetlb-remove-unused-argument-of-follow_huge_pmdpud.patch
mm-introduce-do_shared_fault-and-drop-do_fault-fix-fix.patch
do_shared_fault-check-that-mmap_sem-is-held.patch

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