When the BPX.DAEMON profile is defined in the FACILITY class, any program loaded in the address space where the su command is running must be defined to program control. Because an uncontrolled program has been loaded, the address space is marked "dirty".
The command ends.
Check the system log for any messages from the security product indicating that the environment has become uncontrolled. (For example, ICH420I may be issued by RACF®.) Define the programs or libraries to program control. Either use the RDEFINE command to define the program or library to the RACF PROGRAM class, or use the extattr +p shell command for a z/OS® UNIX executable file. Verify that the /bin/su file has the "p" extended attribute and does not have the "s" extended attribute.
Contact your system programmer.