To address the following error while start a listener on OL6, set LD_BIND_NOW to 1. This variable may have to be set in the context of a EMCC agent.
$ lsnrctl start LISTENER_DBCLONE LSNRCTL for Linux: Version 12.1.0.2.0 - Production on 02-AUG-2018 15:27:07 Copyright (c) 1991, 2014, Oracle. All rights reserved. Starting /u01/app/oracle/product/12.1.0.2/dbhome_1/bin/tnslsnr: please wait... TNS-12537: TNS:connection closed TNS-12560: TNS:protocol adapter error TNS-00507: Connection closed Linux Error: 29: Illegal seek
$ export LD_BIND_NOW=1
$ lsnrctl start LISTENER_DBCLONE LSNRCTL for Linux: Version 12.1.0.2.0 - Production on 02-AUG-2018 15:28:08 Copyright (c) 1991, 2014, Oracle. All rights reserved. Starting /u01/app/oracle/product/12.1.0.2/dbhome_1/bin/tnslsnr: please wait... TNSLSNR for Linux: Version 12.1.0.2.0 - Production System parameter file is /u01/app/oracle/product/12.1.0.2/dbhome_1/network/admin/listener.ora Log messages written to /u01/app/oracle/diag/tnslsnr/<myhost>/listener_dbclone/alert/log.xml Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=<myhost>.<mydomain>)(PORT=1523))) Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=<myhost>.<mydomain>)(PORT=1523))) STATUS of the LISTENER ------------------------ Alias LISTENER_DBCLONE ... The command completed successfully