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

This patch was dropped because an updated version will be merged

------------------------------------------------------
From: Naoya Horiguchi <[email protected]>
Subject: mm/hugetlb: add migration/hwpoisoned 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.  HWPoison entries also can cause the same
problem.

This patch adds is_hugetlb_entry_(migration|hwpoisoned) check in this
function to do proper actions.

Signed-off-by: Naoya Horiguchi <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: James Hogan <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: <[email protected]>    [2.6.36+]
Signed-off-by: Andrew Morton <[email protected]>
---

 mm/hugetlb.c |   21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

diff -puN 
mm/hugetlb.c~mm-hugetlb-add-migration-hwpoisoned-entry-check-in-hugetlb_change_protection
 mm/hugetlb.c
--- 
a/mm/hugetlb.c~mm-hugetlb-add-migration-hwpoisoned-entry-check-in-hugetlb_change_protection
+++ a/mm/hugetlb.c
@@ -3372,7 +3372,26 @@ 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_hwpoisoned(pte))) {
+                       spin_unlock(ptl);
+                       continue;
+               }
+               if (unlikely(is_hugetlb_entry_migration(pte))) {
+                       swp_entry_t entry = pte_to_swp_entry(pte);
+
+                       if (is_write_migration_entry(entry)) {
+                               pte_t newpte;
+
+                               make_migration_entry_read(&entry);
+                               newpte = swp_entry_to_pte(entry);
+                               set_huge_pte_at(mm, address, ptep, newpte);
+                               pages++;
+                       }
+                       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 [email protected] are

memory-hotplug-add-sysfs-zones_online_to-attribute.patch
memory-hotplug-add-sysfs-zones_online_to-attribute-fix-3.patch
memory-hotplug-add-sysfs-zones_online_to-attribute-fix-4.patch
mm-thp-dont-hold-mmap_sem-in-khugepaged-when-allocating-thp.patch
mm-compaction-defer-each-zone-individually-instead-of-preferred-zone.patch
mm-compaction-defer-each-zone-individually-instead-of-preferred-zone-fix.patch
mm-compaction-do-not-count-compact_stall-if-all-zones-skipped-compaction.patch
mm-compaction-do-not-recheck-suitable_migration_target-under-lock.patch
mm-compaction-move-pageblock-checks-up-from-isolate_migratepages_range.patch
mm-compaction-reduce-zone-checking-frequency-in-the-migration-scanner.patch
mm-compaction-khugepaged-should-not-give-up-due-to-need_resched.patch
mm-compaction-khugepaged-should-not-give-up-due-to-need_resched-fix.patch
mm-compaction-periodically-drop-lock-and-restore-irqs-in-scanners.patch
mm-compaction-skip-rechecks-when-lock-was-already-held.patch
mm-compaction-remember-position-within-pageblock-in-free-pages-scanner.patch
mm-compaction-skip-buddy-pages-by-their-order-in-the-migrate-scanner.patch
mm-rename-allocflags_to_migratetype-for-clarity.patch
mm-compaction-pass-gfp-mask-to-compact_control.patch
mempolicy-change-alloc_pages_vma-to-use-mpol_cond_put.patch
mempolicy-change-get_task_policy-to-return-default_policy-rather-than-null.patch
mempolicy-sanitize-the-usage-of-get_task_policy.patch
mempolicy-remove-the-task-arg-of-vma_policy_mof-and-simplify-it.patch
mempolicy-introduce-__get_vma_policy-export-get_task_policy.patch
mempolicy-fix-show_numa_map-vs-exec-do_set_mempolicy-race.patch
mempolicy-kill-do_set_mempolicy-down_writemm-mmap_sem.patch
mempolicy-unexport-get_vma_policy-and-remove-its-task-arg.patch
introduce-dump_vma.patch
introduce-dump_vma-fix.patch
introduce-vm_bug_on_vma.patch
convert-a-few-vm_bug_on-callers-to-vm_bug_on_vma.patch
mm-softdirty-unmapped-addresses-between-vmas-are-clean.patch
mm-softdirty-unmapped-addresses-between-vmas-are-clean-v2.patch
mm-hugetlb-add-migration-entry-check-in-__unmap_hugepage_range.patch
mm-introduce-do_shared_fault-and-drop-do_fault-fix-fix.patch
do_shared_fault-check-that-mmap_sem-is-held.patch
mm-softdirty-enable-write-notifications-on-vmas-after-vm_softdirty-cleared.patch
mm-softdirty-enable-write-notifications-on-vmas-after-vm_softdirty-cleared-fix.patch

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