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 it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
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.
Fixes: 290408d4a2 ("hugetlb: hugepage migration core")
Signed-off-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: James Hogan <james.hogan@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Mel Gorman <mel@xxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Luiz Capitulino <lcapitulino@xxxxxxxxxx>
Cc: Nishanth Aravamudan <nacc@xxxxxxxxxxxxxxxxxx>
Cc: Lee Schermerhorn <lee.schermerhorn@xxxxxx>
Cc: Steve Capper <steve.capper@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> [2.6.36+]
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
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
@@ -3384,7 +3384,26 @@ 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 n-horiguchi@xxxxxxxxxxxxx are
origin.patch
mm-hwpoison-drop-lru_add_drain_all-in-__soft_offline_page.patch
do_shared_fault-check-that-mmap_sem-is-held.patch
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