Check during communicator creation that we didn't get assigned a CID we can't handle, so that the code aborts instead of hange.

Refs trac:1904

This commit was SVN r21133.

The following Trac tickets were found above:
  Ticket 1904 --> https://svn.open-mpi.org/trac/ompi/ticket/1904

ompi/mca/pml/cm/pml_cm.c

@@ -82,6 +82,11 @@ mca_pml_cm_enable(bool enable)
 int
 mca_pml_cm_add_comm(ompi_communicator_t* comm)
 {
+    /* should never happen, but it was, so check */
+    if (comm->c_contextid > ompi_pml_cm.super.pml_max_contextid) {
+        return OMPI_ERR_OUT_OF_RESOURCE;
+    }
+
     /* setup our per-communicator data */
     comm->c_pml_comm = NULL;
 

ompi/mca/pml/ob1/pml_ob1.c

@@ -183,6 +183,13 @@ int mca_pml_ob1_add_comm(ompi_communicator_t* comm)
     if (NULL == pml_comm) {
         return OMPI_ERR_OUT_OF_RESOURCE;
     }
+
+    /* should never happen, but it was, so check */
+    if (comm->c_contextid > mca_pml_ob1.super.pml_max_contextid) {
+        OBJ_RELEASE(pml_comm);
+        return OMPI_ERR_OUT_OF_RESOURCE;
+    }
+
     mca_pml_ob1_comm_init_size(pml_comm, comm->c_remote_group->grp_proc_count);
     comm->c_pml_comm = pml_comm;