If the page_move_anon_rmap() is refiling a pmd-splitted THP mapped in
a tail page from a pte, the "address" must be THP aligned in order for
the page->index bugcheck to pass in the CONFIG_DEBUG_VM=y builds.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Fixes: 6d0a07edd17c ("mm: thp: calculate the mapcount correctly for THP pages during WP faults")
Cc: <stable@xxxxxxxxxxxxxxx> [4.5]
Reported-and-Tested-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
Reviewed-by: Andrea Arcangeli <aarcange@xxxxxxxxxx
---
mm/rmap.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/mm/rmap.c b/mm/rmap.c
index 8a839935b18c..0ea5d9071b32 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1098,6 +1098,8 @@ void page_move_anon_rmap(struct page *page,
VM_BUG_ON_PAGE(!PageLocked(page), page);
VM_BUG_ON_VMA(!anon_vma, vma);
+ if (IS_ENABLED(CONFIG_DEBUG_VM) && PageTransHuge(page))
+ address &= HPAGE_PMD_MASK;
VM_BUG_ON_PAGE(page->index != linear_page_index(vma, address), page);
anon_vma = (void *) anon_vma + PAGE_MAPPING_ANON;
--
2.8.1
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