From: Pekka Enberg <penberg@cs.helsinki.fi>
Date: Wed, 7 Apr 2010 16:23:41 +0000 (+0300)
Subject: slub: Fix kmem_ptr_validate() for non-kernel pointers
X-Git-Tag: v2.6.34-rc4~14
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=d3e06e2b15590b70ea73733fc4612e4741ff46e0;p=platform%2Fkernel%2Flinux-exynos.git

slub: Fix kmem_ptr_validate() for non-kernel pointers

As suggested by Linus, fix up kmem_ptr_validate() to handle non-kernel pointers
more graciously. The patch changes kmem_ptr_validate() to use the newly
introduced kern_ptr_validate() helper to check that a pointer is a valid kernel
pointer before we attempt to convert it into a 'struct page'.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Nick Piggin <npiggin@suse.de>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Acked-by: Christoph Lameter <cl@linux-foundation.org>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/mm/slub.c b/mm/slub.c
index b364844..7d6c8b1 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2386,6 +2386,9 @@ int kmem_ptr_validate(struct kmem_cache *s, const void *object)
 {
 	struct page *page;
 
+	if (!kern_ptr_validate(object, s->size))
+		return 0;
+
 	page = get_object_page(object);
 
 	if (!page || s != page->slab)