diff --git a/ompi/mca/coll/ml/coll_ml_mca.c b/ompi/mca/coll/ml/coll_ml_mca.c
index b99422cc98..13d6dd370e 100644
--- a/ompi/mca/coll/ml/coll_ml_mca.c
+++ b/ompi/mca/coll/ml/coll_ml_mca.c
@@ -50,7 +50,8 @@ enum {
 mca_base_var_enum_value_t fragmentation_enable_enum[] = {
     {0, "disable"},
     {1, "enable"},
-    {2, "auto"}
+    {2, "auto"},
+    {-1, NULL}
 };
 
 /*