| From 0798d3c022dc63eb0ec02b511e1f76ca8411ef8e Mon Sep 17 00:00:00 2001 |
| From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> |
| Date: Fri, 27 May 2016 14:27:38 -0700 |
| Subject: mm: thp: avoid false positive VM_BUG_ON_PAGE in page_move_anon_rmap() |
| |
| From: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> |
| |
| commit 0798d3c022dc63eb0ec02b511e1f76ca8411ef8e upstream. |
| |
| 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: 6d0a07edd17c ("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> |
| Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
| Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| mm/rmap.c | 2 ++ |
| 1 file changed, 2 insertions(+) |
| |
| --- a/mm/rmap.c |
| +++ b/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; |