From 239f49c0800778c863585a103805c58afbad6748 Mon Sep 17 00:00:00 2001
From: MinChan Kim <minchan.kim@gmail.com>
Date: Mon, 19 May 2008 22:12:08 +0900
Subject: [PATCH 1/2] slob: Fix to return wrong pointer
Although slob_alloc return NULL, __kmalloc_node returns NULL + align.
Because align always can be changed, it is very hard for debugging
problem of no page if it don't return NULL.
We have to return NULL in case of no page.
[penberg@cs.helsinki.fi: fix formatting as suggested by Matt.]
Acked-by: Matt Mackall <mpm@selenic.com>
Signed-off-by: MinChan Kim <minchan.kim@gmail.com>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
---
mm/slob.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/mm/slob.c b/mm/slob.c
index 6038cbadf796..a3ad6671adf1 100644
--- a/mm/slob.c
+++ b/mm/slob.c
@@ -469,8 +469,9 @@ void *__kmalloc_node(size_t size, gfp_t gfp, int node)
return ZERO_SIZE_PTR;
m = slob_alloc(size + align, gfp, align, node);
- if (m)
- *m = size;
+ if (!m)
+ return NULL;
+ *m = size;
return (void *)m + align;
} else {
void *ret;
From 76994412f8e824e79a593d6777ec327d85f942b2 Mon Sep 17 00:00:00 2001
From: Pekka Enberg <penberg@cs.helsinki.fi>
Date: Thu, 22 May 2008 19:22:25 +0300
Subject: [PATCH 2/2] slub: ksize() abuse checks
Add a WARN_ON for pages that don't have PageSlab nor PageCompound set to catch
the worst abusers of ksize() in the kernel.
Acked-by: Christoph Lameter <clameter@sgi.com>
Cc: Matt Mackall <mpm@selenic.com>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
---
mm/slub.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/mm/slub.c b/mm/slub.c
index a505a828ef41..0987d1cd943c 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2726,9 +2726,10 @@ size_t ksize(const void *object)
page = virt_to_head_page(object);
- if (unlikely(!PageSlab(page)))
+ if (unlikely(!PageSlab(page))) {
+ WARN_ON(!PageCompound(page));
return PAGE_SIZE << compound_order(page);
-
+ }
s = page->slab;
#ifdef CONFIG_SLUB_DEBUG