From 6286ae97d10ea2b5cd90532163797ab217bfdbdf Mon Sep 17 00:00:00 2001
From: Christoph Lameter <cl@linux.com>
Date: Fri, 3 May 2013 15:43:18 +0000
Subject: [PATCH] slab: Return NULL for oversized allocations
The inline path seems to have changed the SLAB behavior for very large
kmalloc allocations with commit e3366016 ("slab: Use common
kmalloc_index/kmalloc_size functions"). This patch restores the old
behavior but also adds diagnostics so that we can figure where in the
code these large allocations occur.
Reported-and-tested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Christoph Lameter <cl@linux.com>
Link: http://lkml.kernel.org/r/201305040348.CIF81716.OStQOHFJMFLOVF@I-love.SAKURA.ne.jp
[ penberg@kernel.org: use WARN_ON_ONCE ]
Signed-off-by: Pekka Enberg <penberg@kernel.org>
---
include/linux/slab_def.h | 6 ++++++
mm/slab_common.c | 3 +++
2 files changed, 9 insertions(+)
diff --git a/include/linux/slab_def.h b/include/linux/slab_def.h
index 113ec080313fd..cd401580bdd30 100644
--- a/include/linux/slab_def.h
+++ b/include/linux/slab_def.h
@@ -126,6 +126,9 @@ static __always_inline void *kmalloc(size_t size, gfp_t flags)
if (!size)
return ZERO_SIZE_PTR;
+ if (WARN_ON_ONCE(size > KMALLOC_MAX_SIZE))
+ return NULL;
+
i = kmalloc_index(size);
#ifdef CONFIG_ZONE_DMA
@@ -172,6 +175,9 @@ static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
if (!size)
return ZERO_SIZE_PTR;
+ if (WARN_ON_ONCE(size > KMALLOC_MAX_SIZE))
+ return NULL;
+
i = kmalloc_index(size);
#ifdef CONFIG_ZONE_DMA
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 2f0e7d5976cb9..c5d352e73d81f 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -373,6 +373,9 @@ struct kmem_cache *kmalloc_slab(size_t size, gfp_t flags)
{
int index;
+ if (WARN_ON_ONCE(size > KMALLOC_MAX_SIZE))
+ return NULL;
+
if (size <= 192) {
if (!size)
return ZERO_SIZE_PTR;
--
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