Gen TISRVMSL error handling problems under z/OS 2.5

Products

• Gen - Run Time Distributed
• Gen

Issue/Introduction

After upgrading to z/OS 2.5 seeing problems with the Gen Multi Sockets CICS Listener TISRVMSL and its error handling.
After some time since the TISRVMSL was started, these symptoms may start to appear:

1. The server-side CICS MSGUSR log will contain many messages of the form: 
TISRVMSL TIML TASK=######## MM/DD/YYYY HH:MM:SS START TRANSACTION FAILED FOR TRAN Gen_Server_Trancode
TISRVMSL TIML TASK=######## MM/DD/YYYY HH:MM:SS CICS ERROR, RESPONSE=00000069, RESP2=00000008     

TISRVMSL TIML TASK=######## MM/DD/YYYY HH:MM:SS LISTENER TAKESOCKET BACK FAILED FOR SERVER Gen_Server_Trancode 
TISRVMSL TIML TASK=######## MM/DD/YYYY HH:MM:SS SOCKET ERROR, RETCODE=-0000001, ERRNO=00001002
 
TISRVMSL TIML TASK=######## MM/DD/YYYY HH:MM:SS ACCEPT CALL FAILED      
TISRVMSL TIML TASK=######## MM/DD/YYYY HH:MM:SS SOCKET ERROR, RETCODE=-0000001, ERRNO=00001002

NOTE: RESPONSE=00000069 means USERIDERR and RESP2=00000008 means the USERID is unknown,  thus the above error situation is for a security failure. 


2. Client connections may hang/loop/spin when a security violation occurs instead of returning the expected message "TIRM621E: Error creating semaphore, can't access server"
Also, the MSGUSR log does not contain the expected message "GIVESOCKET NOT TAKEN".
(Gen EDGE Community post: Security violations behavior has changed in GUI client-server)

Environment

Gen 8.6 COBOL/CICS Distributed Process servers using TISRVMSL under z/OS 2.5

Cause

There is a known TISRVMSL problem that only seems to get exposed with TCP/IP changes under z/OS 2.5.
The TISRVMSL error handling of conditions like security violations/failures does not release the current socket and eventually, the available socket pool is exhausted.

Resolution

Workaround: Recycle the TISRVMSL 

Resolution: Apply Gen 8.6 PTF LU08295 ("TISRVMSL LOOPS/DOES NOT PROCESS SOCKETS WHEN HANDLING ERRORS") 
NOTE: This PTF only affects TISRVMSL, as it fixes a problem with socket management handling when sending the error response. It does not impact the actual Gen servers so the PTF should be relatively easy to deploy.   

Additional Information

Communications and Middleware