The patch titled
Subject: mm: hwpoison: drop lru_add_drain_all() in __soft_offline_page()
has been added to the -mm tree. Its filename is
mm-hwpoison-drop-lru_add_drain_all-in-__soft_offline_page.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-hwpoison-drop-lru_add_drain_all-in-__soft_offline_page.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-hwpoison-drop-lru_add_drain_all-in-__soft_offline_page.patch
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------------------------------------------------------
From: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Subject: mm: hwpoison: drop lru_add_drain_all() in __soft_offline_page()
A race condition starts to be visible in recent mmotm, where a PG_hwpoison
flag is set on a migration source page *before* it's back in buddy page
poo= l.
This is problematic because no page flag is supposed to be set when
freeing (see __free_one_page().) So the user-visible effect of this race
is that it could trigger the BUG_ON() when soft-offlining is called.
The root cause is that we call lru_add_drain_all() to make sure that the
page is in buddy, but that doesn't work because this function just
schedule= s a work item and doesn't wait its completion.
drain_all_pages() does drainin= g directly, so simply dropping
lru_add_drain_all() solves this problem.
Fixes: f15bdfa802bf ("mm/memory-failure.c: fix memory leak in successful soft offlining")
Signed-off-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: Andi Kleen <andi@xxxxxxxxxxxxxx>
Cc: Tony Luck <tony.luck@xxxxxxxxx>
Cc: Chen Gong <gong.chen@xxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> [3.11+]
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory-failure.c | 2 --
1 file changed, 2 deletions(-)
diff -puN mm/memory-failure.c~mm-hwpoison-drop-lru_add_drain_all-in-__soft_offline_page mm/memory-failure.c
--- a/mm/memory-failure.c~mm-hwpoison-drop-lru_add_drain_all-in-__soft_offline_page
+++ a/mm/memory-failure.c
@@ -1647,8 +1647,6 @@ static int __soft_offline_page(struct pa
* setting PG_hwpoison.
*/
if (!is_free_buddy_page(page))
- lru_add_drain_all();
- if (!is_free_buddy_page(page))
drain_all_pages(page_zone(page));
SetPageHWPoison(page);
if (!is_free_buddy_page(page))
_
Patches currently in -mm which might be from n-horiguchi@xxxxxxxxxxxxx are
hugetlb-x86-register-1g-page-size-if-we-can-allocate-them-runtime.patch
mm-add-kpf_zero_page-flag-for-proc-kpageflags.patch
mm-hugetlb-reduce-arch-dependent-code-around-follow_huge_.patch
mm-hugetlb-pmd_huge-returns-true-for-non-present-hugepage.patch
mm-hugetlb-take-page-table-lock-in-follow_huge_pmd.patch
mm-hugetlb-fix-getting-refcount-0-page-in-hugetlb_fault.patch
mm-hugetlb-add-migration-hwpoisoned-entry-check-in-hugetlb_change_protection.patch
mm-hugetlb-add-migration-entry-check-in-__unmap_hugepage_range.patch
proc-pagemap-walk-page-tables-under-pte-lock.patch
mm-pagewalk-remove-pgd_entry-and-pud_entry.patch
pagewalk-improve-vma-handling.patch
pagewalk-add-walk_page_vma.patch
smaps-remove-mem_size_stats-vma-and-use-walk_page_vma.patch
clear_refs-remove-clear_refs_private-vma-and-introduce-clear_refs_test_walk.patch
pagemap-use-walk-vma-instead-of-calling-find_vma.patch
numa_maps-fix-typo-in-gather_hugetbl_stats.patch
numa_maps-remove-numa_maps-vma.patch
memcg-cleanup-preparation-for-page-table-walk.patch
arch-powerpc-mm-subpage-protc-use-walk-vma-and-walk_page_vma.patch
mempolicy-apply-page-table-walker-on-queue_pages_range.patch
mm-pagewalk-fix-misbehavior-of-walk_page_range-for-vmavm_pfnmap-re-pagewalk-improve-vma-handling.patch
mm-proc-pid-clear_refs-avoid-split_huge_page.patch
mincore-apply-page-table-walker-on-do_mincore.patch
mincore-apply-page-table-walker-on-do_mincore-fix.patch
mincore-apply-page-table-walker-on-do_mincore-fix-fix.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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