S0C1 abends in CICS after CCS maintenance

Products

• COMMON SERVICES FOR Z/OS

Issue/Introduction

After applying maintenance to Common Component Services for z/OS (CCS), it can happen the below abend and messages appear in the CICS environments.

CICA     24260 23:47:33.89 S0124336 00000281  IEA995I SYMPTOM DUMP OUTPUT 799                                
                                799 00000281  SYSTEM COMPLETION CODE=0C1  REASON CODE=00000001               
                                799 00000281   TIME=23.47.33  SEQ=54704  CPU=0000  ASID=00AA                 
                                799 00000281   PSW AT TIME OF ERROR  478D1000   80000002  ILC 2  INTC 01     
                                799 00000281     NO ACTIVE MODULE FOUND                                      
                                799 00000281     NAME=UNKNOWN                                                
                                799 00000281     DATA AT PSW  00000000 - 00000000  00000000  00000000        
                                799 00000281     GR 0: 00000010   1: 5FE2A6D8                                
                                799 00000281        2: 5FE68F18   3: 00000000                                
                                799 00000281        4: 00000000   5: 00000000                                
                                799 00000281        6: 00000000   7: 00000000                                
                                799 00000281        8: 00000000   9: 00000000                                
                                799 00000281        A: 00000000   B: 00000000                                
                                799 00000281        C: 00000000   D: 5FE2AF70                                
                                799 00000281        E: 00FD7F30   F: 80000000                                
                                799 00000281   END OF SYMPTOM DUMP                                           

Cause

The problem is caused by one of the CCS ptfs that hit the ENF/CICS modules. In this situation PTF LU09407.

Resolution

After the recycle of ENF with the REINIT option (S ENF,,,REINIT), it's needed also to recycle (stop and start) the CICS environment.
After the restart of CICS, there should be no abend anymore.

Additional Information

In most cases it is not necessary to recycle the CICS region if ENF is refreshed by a recycle when maintenance is implemented, the ENF/CICS code is able to detect the updated code and modify it's pointers accordingly.
This however was a unique situation where the structure of the stub code for the ENF/CICS intercepts which is a permanent structure CICS region changed but there is no way to rebuild these stubs without a CICS recycle.
Changes to the stubs happen very rarely so it was an oversite on our part not to have made the recycle of the CICS regions part of the implementation instructions.