Make an attempt to protect hwloc cset2str from segfaulting in weird scenario

This commit was SVN r27361.

orte/mca/odls/default/odls_default_module.c

@@ -497,10 +497,14 @@ static int do_child(orte_app_context_t* context,
                 }
                 if (0 == rc && opal_hwloc_report_bindings) {
                     char tmp1[1024], tmp2[1024];
-                    opal_hwloc_base_cset2str(tmp1, sizeof(tmp1), cpuset);
-                    opal_hwloc_base_cset2mapstr(tmp2, sizeof(tmp2), cpuset);
-                    opal_output(0, "MCW rank %d bound to %s: %s",
-                                child->name.vpid, tmp1, tmp2);
+                    if (NULL == cpuset) {
+                        opal_output(0, "Cannot print NULL cpuset");
+                    } else {
+                        opal_hwloc_base_cset2str(tmp1, sizeof(tmp1), cpuset);
+                        opal_hwloc_base_cset2mapstr(tmp2, sizeof(tmp2), cpuset);
+                        opal_output(0, "MCW rank %d bound to %s: %s",
+                                    child->name.vpid, tmp1, tmp2);
+                    }
                 }
                 /* set memory affinity policy */
                 if (ORTE_SUCCESS != opal_hwloc_base_set_process_membind_policy()) {