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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org,
	Carsten Emde <C.Emde@osadl.org>, Christoph Lameter <cl@linux.com>,
	Pekka Enberg <penberg@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Subject: [PATCH 08/12] FIX [1/2] slub: Do not dereference NULL pointer in node_match
Date: Wed, 13 Feb 2013 17:13:47 +0100	[thread overview]
Message-ID: <1360772031-27186-9-git-send-email-bigeasy@linutronix.de> (raw)
In-Reply-To: <1360772031-27186-1-git-send-email-bigeasy@linutronix.de>

From: Christoph Lameter <cl@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>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[bigeasy@linutronix: replace page with c->page]
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 mm/slub.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/slub.c b/mm/slub.c
index 71de9b5..fbf6810 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2058,7 +2058,7 @@ static void flush_all(struct kmem_cache *s)
 static inline int node_match(struct kmem_cache_cpu *c, int node)
 {
 #ifdef CONFIG_NUMA
-	if (node != NUMA_NO_NODE && c->node != node)
+	if (!c->page || (node != NUMA_NO_NODE && c->node != node))
 		return 0;
 #endif
 	return 1;
-- 
1.7.10.4


  parent reply	other threads:[~2013-02-13 16:14 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-02-13 16:13 [PREEMPT RT] SLUB and split softirq lock for v3.4-rt Sebastian Andrzej Siewior
2013-02-13 16:13 ` [PATCH 01/12] softirq: Make serving softirqs a task flag Sebastian Andrzej Siewior
2013-02-13 16:13 ` [PATCH 02/12] softirq: Split handling function Sebastian Andrzej Siewior
2013-02-13 16:13 ` [PATCH 03/12] softirq: Split softirq locks Sebastian Andrzej Siewior
2013-02-13 16:13 ` [PATCH 04/12] softirq: Adapt NOHZ softirq pending check to new RT scheme Sebastian Andrzej Siewior
2013-02-13 16:13 ` [PATCH 05/12] softirq: Add more debugging Sebastian Andrzej Siewior
2013-02-13 16:13 ` [PATCH 06/12] softirq: Fix nohz pending issue for real Sebastian Andrzej Siewior
2013-02-13 16:13 ` [PATCH 07/12] net: Use local_bh_disable in netif_rx_ni() Sebastian Andrzej Siewior
2013-02-13 16:13 ` Sebastian Andrzej Siewior [this message]
2013-02-13 16:13 ` [PATCH 09/12] FIX [2/2] slub: Tid must be retrieved from the percpu area of the current processor Sebastian Andrzej Siewior
2013-02-13 16:13 ` [PATCH 10/12] slub: Use correct cpu_slab on dead cpu Sebastian Andrzej Siewior
2013-02-13 16:13 ` [PATCH 11/12] mm: Enable SLUB for RT Sebastian Andrzej Siewior
2013-02-13 16:13 ` [PATCH 12/12] slub: Enable irqs for __GFP_WAIT Sebastian Andrzej Siewior

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