From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx> Subject: 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. Link: http://lkml.kernel.org/r/1464253620-106404-1-git-send-email-kirill.shutemov@xxxxxxxxxxxxxxx Fixes: 6d0a07edd17c ("mm: thp: calculate the mapcount correctly for THP pages during WP faults") Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> Reported-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> Tested-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> Reviewed-by: Andrea Arcangeli <aarcange@xxxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> [4.5] Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/rmap.c | 2 ++ 1 file changed, 2 insertions(+) diff -puN mm/rmap.c~mm-thp-avoid-false-positive-vm_bug_on_page-in-page_move_anon_rmap mm/rmap.c --- a/mm/rmap.c~mm-thp-avoid-false-positive-vm_bug_on_page-in-page_move_anon_rmap +++ a/mm/rmap.c @@ -1098,6 +1098,8 @@ void page_move_anon_rmap(struct page *pa 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; _ -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html