diff --git a/ompi/datatype/dt_args.c b/ompi/datatype/dt_args.c
index 9822365e2a..d4c1fccbfe 100644
--- a/ompi/datatype/dt_args.c
+++ b/ompi/datatype/dt_args.c
@@ -363,7 +363,11 @@ int ompi_ddt_get_pack_description( ompi_datatype_t* datatype,
     void* recursive_buffer;
 
     if( NULL == datatype->packed_description ) {
-        datatype->packed_description = malloc( args->total_pack_size );
+        if( datatype->flags & DT_FLAG_PREDEFINED ) {
+            datatype->packed_description = malloc( 2 * sizeof(int) );
+        } else {
+            datatype->packed_description = malloc( args->total_pack_size );
+        }
         recursive_buffer = datatype->packed_description;
         __ompi_ddt_pack_description( datatype, &recursive_buffer, &next_index );
     }
diff --git a/ompi/datatype/dt_module.c b/ompi/datatype/dt_module.c
index 8aa69a201a..7c180a8f7c 100644
--- a/ompi/datatype/dt_module.c
+++ b/ompi/datatype/dt_module.c
@@ -399,9 +399,6 @@ int32_t ompi_ddt_init( void )
         datatype->desc.length       = 1;
         datatype->desc.used         = 1;
         datatype->btypes[i]         = 1;
-        datatype->packed_description = malloc(2 * sizeof(int) );
-        ((int*)(datatype->packed_description))[0] = MPI_COMBINER_DUP;
-        ((int*)(datatype->packed_description))[1] = i;
     }
 
     /* Create the f2c translation table */