diff --git a/[refs] b/[refs]
index b15bdbd88dca..507be9f5f097 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 4997b72ee62930cb841d185398ea547d979789f4
+refs/heads/master: ac4e97abce9b80c020e7113325f49e58b7b15e3f
diff --git a/trunk/include/linux/scatterlist.h b/trunk/include/linux/scatterlist.h
index 5951e3f38878..26806775b11b 100644
--- a/trunk/include/linux/scatterlist.h
+++ b/trunk/include/linux/scatterlist.h
@@ -111,6 +111,9 @@ static inline struct page *sg_page(struct scatterlist *sg)
 static inline void sg_set_buf(struct scatterlist *sg, const void *buf,
 			      unsigned int buflen)
 {
+#ifdef CONFIG_DEBUG_SG
+	BUG_ON(!virt_addr_valid(buf));
+#endif
 	sg_set_page(sg, virt_to_page(buf), buflen, offset_in_page(buf));
 }