From f04ff79df6be5ae086b973ecd189ac7a1e920094 Mon Sep 17 00:00:00 2001
From: Christoph Lameter <cl@linux.com>
Date: Mon, 16 May 2011 15:26:08 -0500
Subject: [PATCH] --- yaml --- r: 248624 b: refs/heads/master c:
 1393d9a1857471f816d0be1ccc1d6433a86050f6 h: refs/heads/master v: v3

---
 [refs]          |  2 +-
 trunk/mm/slub.c | 14 +++++++++++++-
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/[refs] b/[refs]
index f5e762fde197..84f41ceff542 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 6332aa9d25e911cc97aa9cc09acee21afda07ea6
+refs/heads/master: 1393d9a1857471f816d0be1ccc1d6433a86050f6
diff --git a/trunk/mm/slub.c b/trunk/mm/slub.c
index 8657ab838b82..97bb5b8d935f 100644
--- a/trunk/mm/slub.c
+++ b/trunk/mm/slub.c
@@ -261,6 +261,18 @@ static inline void *get_freepointer(struct kmem_cache *s, void *object)
 	return *(void **)(object + s->offset);
 }
 
+static inline void *get_freepointer_safe(struct kmem_cache *s, void *object)
+{
+	void *p;
+
+#ifdef CONFIG_DEBUG_PAGEALLOC
+	probe_kernel_read(&p, (void **)(object + s->offset), sizeof(p));
+#else
+	p = get_freepointer(s, object);
+#endif
+	return p;
+}
+
 static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp)
 {
 	*(void **)(object + s->offset) = fp;
@@ -1933,7 +1945,7 @@ static __always_inline void *slab_alloc(struct kmem_cache *s,
 		if (unlikely(!this_cpu_cmpxchg_double(
 				s->cpu_slab->freelist, s->cpu_slab->tid,
 				object, tid,
-				get_freepointer(s, object), next_tid(tid)))) {
+				get_freepointer_safe(s, object), next_tid(tid)))) {
 
 			note_cmpxchg_failure("slab_alloc", s, tid);
 			goto redo;