Question & Answer
Has something changed in CICS Transaction Server for z/OS (CICS TS) V5.3 that would cause a protection exception S0C4? I upgraded from CICS TS 5.1 to CICS TS 5.3 and suddenly began to receive messages:
DFHSR0622 applid An attempt to overwrite the ECDSA has caused the abend which follows
CEE3204S The system detected a protection exception (System Completion Code=0C4).
The DFHSR0622 message and abend 0C4 disappear again when I roll back to CICS TS 5.1.
CICS TS 5.3 changed the default setting of the system initialization table (SIT) parameter STGPROT. It now defaults to STGPROT(YES). The default was STGPROT(NO) in CICS TS 5.2 and below. Because the default changed to turn on storage protection by default and the application program was defined with EXECKEY(USER), any attempt to access ECDSA by the application caused message DFHSR0622 and an abend0C4.
The resolution is turn off storage protection by changing the SIT parameter to STGPROT(NO) or to change the Program definition from EXECKEY(USER) to EXECKEY(CICS).
See EXECKEY option in the CICS TS documentation for a better understanding of why you might want to specify EXECKEY(USER).
CICS/TS CICSTS CICS TS CICS Transaction Server
08 May 2017