Index: sys/powerpc/powernv/platform_powernv.c
===================================================================
--- sys/powerpc/powernv/platform_powernv.c
+++ sys/powerpc/powernv/platform_powernv.c
@@ -519,15 +519,21 @@
 
 	res = OF_getproplen(node, "ibm,associativity");
 
-	/* If already at the root, use default domain. */
-	if (res == 0)
-		return (0);
-	else if (res < 0)
-		/* If this node doesn't have associativity, check its parent. */
-		return (powernv_node_numa_domain(platform, OF_parent(node)));
+	/* If this node doesn't have associativity, check its parent. */
+	if (res < 0) {
+		node = OF_parent(node);
+		/* If already at the root, use default domain. */
+		if (node == 0)
+			return (0);
+		return (powernv_node_numa_domain(platform, node));
+	}
+
+	KASSERT(res >= sizeof(cell_t) * (platform_associativity + 1),
+	    ("ibm,associativity property has less than "
+	     "platform_associativity (%d) elements", platform_associativity));
 
 	OF_getencprop(node, "ibm,associativity",
-		associativity, res);
+		associativity, sizeof(associativity));
 
 	for (i = 0; i < numa_max_domain; i++) {
 		if (numa_domains[i] == associativity[platform_associativity])