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From: Christoph Lameter <cl@linux.com>
To: Pekka Enberg <penberg@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: RT <linux-rt-users@vger.kernel.org>
Cc: Clark Williams <clark@redhat.com>
Cc: John Kacur <jkacur@gmail.com>
Cc: "Luis Claudio R. Goncalves" <lgoncalv@redhat.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Glauber Costa <glommer@parallels.com>
Cc: linux-mm@kvack.org
Cc: David Rientjes <rientjes@google.com>
Cc: elezegarcia@gmail.com
Subject: FIX [1/2] slub: Do not dereference NULL pointer in node_match
Date: Wed, 23 Jan 2013 21:45:47 +0000	[thread overview]
Message-ID: <0000013c695fbd30-9023bc55-f780-4d44-965f-ab4507e483d5-000000@email.amazonses.com> (raw)
In-Reply-To: 20130123214514.370647954@linux.com

The variables accessed in slab_alloc are volatile and therefore
the page pointer passed to node_match can be NULL. The processing
of data in slab_alloc is tentative until either the cmpxhchg
succeeds or the __slab_alloc slowpath is invoked. Both are
able to perform the same allocation from the freelist.

Check for the NULL pointer in node_match.

A false positive will lead to a retry of the loop in __slab_alloc.

Signed-off-by: Christoph Lameter <cl@linux.com>

Index: linux/mm/slub.c
===================================================================
--- linux.orig/mm/slub.c	2013-01-18 08:47:29.198954250 -0600
+++ linux/mm/slub.c	2013-01-18 08:47:40.579126371 -0600
@@ -2041,7 +2041,7 @@ static void flush_all(struct kmem_cache
 static inline int node_match(struct page *page, int node)
 {
 #ifdef CONFIG_NUMA
-	if (node != NUMA_NO_NODE && page_to_nid(page) != node)
+	if (!page || (node != NUMA_NO_NODE && page_to_nid(page) != node))
 		return 0;
 #endif
 	return 1;

--
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WARNING: multiple messages have this Message-ID (diff)
From: Christoph Lameter <cl@linux.com>
To: Pekka Enberg <penberg@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	RT <linux-rt-users@vger.kernel.org>,
	Clark Williams <clark@redhat.com>, John Kacur <jkacur@gmail.com>,
	"Luis Claudio R. Goncalves" <lgoncalv@redhat.com>,
	Joonsoo Kim <js1304@gmail.com>,
	Glauber Costa <glommer@parallels.com>,
	linux-mm@kvack.org, David Rientjes <rientjes@google.com>,
	elezegarcia@gmail.com
Subject: FIX [1/2] slub: Do not dereference NULL pointer in node_match
Date: Wed, 23 Jan 2013 21:45:47 +0000	[thread overview]
Message-ID: <0000013c695fbd30-9023bc55-f780-4d44-965f-ab4507e483d5-000000@email.amazonses.com> (raw)
In-Reply-To: 20130123214514.370647954@linux.com

The variables accessed in slab_alloc are volatile and therefore
the page pointer passed to node_match can be NULL. The processing
of data in slab_alloc is tentative until either the cmpxhchg
succeeds or the __slab_alloc slowpath is invoked. Both are
able to perform the same allocation from the freelist.

Check for the NULL pointer in node_match.

A false positive will lead to a retry of the loop in __slab_alloc.

Signed-off-by: Christoph Lameter <cl@linux.com>

Index: linux/mm/slub.c
===================================================================
--- linux.orig/mm/slub.c	2013-01-18 08:47:29.198954250 -0600
+++ linux/mm/slub.c	2013-01-18 08:47:40.579126371 -0600
@@ -2041,7 +2041,7 @@ static void flush_all(struct kmem_cache
 static inline int node_match(struct page *page, int node)
 {
 #ifdef CONFIG_NUMA
-	if (node != NUMA_NO_NODE && page_to_nid(page) != node)
+	if (!page || (node != NUMA_NO_NODE && page_to_nid(page) != node))
 		return 0;
 #endif
 	return 1;

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

       reply	other threads:[~2013-01-23 21:45 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20130123214514.370647954@linux.com>
2013-01-23 21:45 ` Christoph Lameter [this message]
2013-01-23 21:45   ` FIX [1/2] slub: Do not dereference NULL pointer in node_match Christoph Lameter
2013-01-24  0:53   ` Simon Jeons
2013-01-24  0:53     ` Simon Jeons
2013-01-24 15:14     ` Christoph Lameter
2013-01-25  8:11       ` Simon Jeons
2013-01-25  8:11         ` Simon Jeons
2013-01-25 14:53         ` Christoph Lameter
2013-02-01 10:23   ` Pekka Enberg
2013-02-01 10:23     ` Pekka Enberg
2013-02-01 11:51     ` Steven Rostedt
2013-02-01 11:51       ` Steven Rostedt
2013-01-23 21:45 ` FIX [2/2] slub: tid must be retrieved from the percpu area of the current processor Christoph Lameter
2013-01-23 21:45   ` Christoph Lameter
2013-02-01 10:24   ` Pekka Enberg
2013-02-01 10:24     ` Pekka Enberg

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