diff options
| author | Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2016-01-16 01:52:07 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-01-16 02:56:32 +0100 |
| commit | 1c290f642101e64f379e38ea0361d097c08e824d (patch) | |
| tree | 14667c7c813fa14f6ce63e3fe7f5d14322fff0a6 /mm/huge_memory.c | |
| parent | page-flags: look at head page if the flag is encoded in page->mapping (diff) | |
| download | linux-1c290f642101e64f379e38ea0361d097c08e824d.tar.xz linux-1c290f642101e64f379e38ea0361d097c08e824d.zip | |
mm: sanitize page->mapping for tail pages
We don't define meaning of page->mapping for tail pages. Currently it's
always NULL, which can be inconsistent with head page and potentially
lead to problems.
Let's poison the pointer to catch all illigal uses.
page_rmapping(), page_mapping() and page_anon_vma() are changed to look
on head page.
The only illegal use I've caught so far is __GPF_COMP pages from sound
subsystem, mapped with PTEs. do_shared_fault() is changed to use
page_rmapping() instead of direct access to fault_page->mapping.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Jérôme Glisse <jglisse@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Jerome Marchand <jmarchan@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/huge_memory.c')
| -rw-r--r-- | mm/huge_memory.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index f952f055fdcf..370d44a5e25b 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1805,7 +1805,7 @@ static void __split_huge_page_refcount(struct page *page, */ page_tail->_mapcount = page->_mapcount; - BUG_ON(page_tail->mapping); + BUG_ON(page_tail->mapping != TAIL_MAPPING); page_tail->mapping = page->mapping; page_tail->index = page->index + i; |