Commit 0798d3c0 authored by Kirill A. Shutemov's avatar Kirill A. Shutemov Committed by Linus Torvalds
Browse files

mm: thp: avoid false positive VM_BUG_ON_PAGE in page_move_anon_rmap()

If 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.

Fixes: 6d0a07ed

 ("mm: thp: calculate the mapcount correctly for THP pages during WP faults")
Signed-off-by: default avatarKirill A. Shutemov <>
Reported-by: default avatarMika Westerberg <>
Tested-by: default avatarMika Westerberg <>
Reviewed-by: default avatarAndrea Arcangeli <>
Cc: <>        [4.5]
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent e2fe1456
......@@ -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;
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