The exit statuses have been modified as follows:

 1 - overall generic failure; this is what used to be 2
 2 - argument parsing failure; generated by pre-processing argument parsing
 3 - generic processing failure
 5 - state failure; some entity in incorrect state for requested action
 6 - system failure; a requested operation from the system failed
 7 - user failure

Examples:
 exit status 5: attempting to perform growPhysical on a stopped vdo
 exit status 6: failed file read
 exit status 7: parameter incongruities which are checked at runtime,
                user running with insufficient permission

Exit status 4 should never be seen; it's used in defensive programming against developer oversight. As an example, consider...

  switch (someValue) {
    case 0:
      // do something
      break;
    case 1:
      / do something else
      break;
    default:
      exit(4);
  }

If the range of someValue is extended without a corresponding change to the switch an exit status of 4 will result.

If a test gets an exit status of 4 it has definitely encountered a bug.

*** Bug 1603478 has been marked as a duplicate of this bug. ***

Added EXIT STATUS section to man page describing the various exit status values.  That is available in build  6.1.1.115.

man page:
EXIT STATUS
       The following are exit statuses that may be encountered during normal operation.  Any other exit status is an abnormal occurrence.

       0      Success.

       1      Non-specific failure.

       2      Pre-processing argument parsing failure.

       3      Non-specific processing failure.

       5      Incorrect state for requested action; e.g., attempting to perform a growPhysical on a stopped vdo.

       6      A requested operation from the system failed; e.g., error from dmsetup(8).

       7      User error; e.g., attempting to create a vdo with the same name as one already existing.


I am getting the different retcodes without any issues.

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2018:3094