kpagecount: add slab page checking because _mapcount is in a union
Add a PageSlab() check before adding the _mapcount value to /kpagecount.
page->_mapcount is in a union with the SLAB structure so for pages
controlled by SLAB, page_mapcount() returns nonsense.
Signed-off-by: Petr Holasek <pholasek@redhat.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Matt Mackall <mpm@selenic.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/proc/page.c b/fs/proc/page.c
index 3b8b4566..b06c674 100644
--- a/fs/proc/page.c
+++ b/fs/proc/page.c
@@ -40,7 +40,7 @@
ppage = pfn_to_page(pfn);
else
ppage = NULL;
- if (!ppage)
+ if (!ppage || PageSlab(ppage))
pcount = 0;
else
pcount = page_mapcount(ppage);