Description of problem:
scsi_check_sense has this code:

        case ILLEGAL_REQUEST:
                if (sshdr.asc == 0x20 || /* Invalid command operation code */
                    sshdr.asc == 0x21 || /* Logical block address out of range */
                    sshdr.asc == 0x24 || /* Invalid field in cdb */
                    sshdr.asc == 0x26) { /* Parameter value invalid */
                        return TARGET_ERROR;
                }
                return SUCCESS;

which then triggers this bit in scsi_decide_disposition:

                        /*
                         * Need to modify host byte to signal a
                         * permanent target failure
                         */
                        set_host_byte(scmd, DID_TARGET_FAILURE);
                        rtn = SUCCESS;

Recent kernels undo this change to the host byte somewhere along the way back to userspace, while RHEL6 leaves this unmodified.  This causes the host_byte to be set erroneously when executing a command with this sense:

$ strace sg_raw -e ioctl -v /dev/sda  12 1 1 0 0 0
ioctl(3, SG_IO, {'S', SG_DXFER_NONE, cmd[6]=[12, 01, 01, 00, 00, 00], mx_sb_len=32, iovec_count=0, dxfer_len=0, timeout=20000, flags=0, status=02, masked_status=01, sb[18]=[70, 00, 05, 00, 00, 00, 00, 0a, 00, 00, 00, 00, 24, 00, 00, 00, 00, 00], host_status=0x10, driver_status=0x8, resid=0, duration=0, info=0x1}) = 0

Then sg_raw emits

SCSI Status: Check Condition 
Sense Information:
sense buffer empty

Version-Release number of selected component (if applicable):
2.6.32-251.el6

How reproducible:
100%

Steps to Reproduce:
1. see above
  
Actual results:
"sense buffer empty"

Expected results:
Sense Information:
 Fixed format, current;  Sense key: Illegal Request
 Additional sense: Invalid field in cdb
 Raw sense data (in hex):
        70 00 05 00 00 00 00 0a  00 00 00 00 24 00 00 00    
        00 00                                               

or similar

Additional info:
This is shown by the scsi-testsuite tests at git://risingtidesystems.com/scsi-testsuite.git. Recent kernels give host_status=0.