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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@linux.intel.com
Fixes: 6d0a07edd1 ("mm: thp: calculate the mapcount correctly for THP pages during WP faults")
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: <stable@vger.kernel.org>        [4.5]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Kirill A. Shutemov 2016-05-27 14:27:38 -07:00 committed by Linus Torvalds
parent e2fe14564d
commit 0798d3c022
1 changed files with 2 additions and 0 deletions
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2
mm/rmap.c
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@ -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;