---
 mm/slab.c |    2 ++
 mm/slob.c |    3 +++
 mm/slub.c |    2 ++
 3 files changed, 7 insertions(+)

Index: linux-2.6/mm/slab.c
===================================================================
--- linux-2.6.orig/mm/slab.c	2008-02-27 11:16:13.000000000 -0800
+++ linux-2.6/mm/slab.c	2008-02-27 11:16:16.000000000 -0800
@@ -3764,6 +3764,8 @@ void kmem_cache_free(struct kmem_cache *
 {
 	unsigned long flags;
 
+	if (unlikely(!objp))
+		return;
 	local_irq_save(flags);
 	debug_check_no_locks_freed(objp, obj_size(cachep));
 	__cache_free(cachep, objp);
Index: linux-2.6/mm/slob.c
===================================================================
--- linux-2.6.orig/mm/slob.c	2008-02-27 11:16:13.000000000 -0800
+++ linux-2.6/mm/slob.c	2008-02-27 11:16:16.000000000 -0800
@@ -581,6 +581,9 @@ EXPORT_SYMBOL(kmem_cache_alloc_node);
 
 static void __kmem_cache_free(void *b, int size)
 {
+	if (unlikely(!b))
+		return;
+
 	if (size < PAGE_SIZE)
 		slob_free(b, size);
 	else
Index: linux-2.6/mm/slub.c
===================================================================
--- linux-2.6.orig/mm/slub.c	2008-02-27 11:16:13.000000000 -0800
+++ linux-2.6/mm/slub.c	2008-02-27 11:16:16.000000000 -0800
@@ -1740,6 +1740,8 @@ void kmem_cache_free(struct kmem_cache *
 {
 	struct page *page;
 
+	if (unlikely(!x))
+		return;
 	page = virt_to_head_page(x);
 
 	slab_free(s, page, x, __builtin_return_address(0));