diff --git a/[refs] b/[refs]
index 0a53e974a3df..d287b7994f89 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: d72ee6be58b7c99a6e8da6584106c5958dae2bf8
+refs/heads/master: 771a37ff4d80b80db3b0df3e7696f14b298c67b7
diff --git a/trunk/arch/sparc/mm/init_64.c b/trunk/arch/sparc/mm/init_64.c
index a7171997adfd..04fd55a6e461 100644
--- a/trunk/arch/sparc/mm/init_64.c
+++ b/trunk/arch/sparc/mm/init_64.c
@@ -1098,7 +1098,14 @@ static int __init grab_mblocks(struct mdesc_handle *md)
 		m->size = *val;
 		val = mdesc_get_property(md, node,
 					 "address-congruence-offset", NULL);
-		m->offset = *val;
+
+		/* The address-congruence-offset property is optional.
+		 * Explicity zero it be identifty this.
+		 */
+		if (val)
+			m->offset = *val;
+		else
+			m->offset = 0UL;
 
 		numadbg("MBLOCK[%d]: base[%llx] size[%llx] offset[%llx]\n",
 			count - 1, m->base, m->size, m->offset);