A fix is available
APAR status
Closed as program error.
Error description
MQ Development finds that the XGWA does not contain a valid pointer to PFPROCESS. In analysis, the main PubSub Daemon task had failed. This was caused by queue SYSTEM.HIERARCHY.STATE being unavailable. Due to a timing window one of the additional PubSub threads started up and attempted to reference the pFProcess field, however that had now been freed and cleared (rendering it invalid). An ABEND0C4 resulted from there. MQ Development will investigate an improvement to serialization between the PubSub threads at startup.
Local fix
Define the queue SYSTEM.HIERARCHY.STATE
Problem summary
**************************************************************** * USERS AFFECTED: All users of IBM MQ for z/OS Version 9 * * Release 1 Modification 0 and Release 2 * * Modification 0. * **************************************************************** * PROBLEM DESCRIPTION: If an error condition is detected * * during startup of the queued Pub/Sub * * Daemon, a timing window exists whereby * * a Pub/Sub subtask may start before the * * Daemon terminates. This may result in * * S0C4 abends in the CHIN for the Pub/Sub * * Daemon and for the Pub/Sub subtask. * **************************************************************** During startup of the Pub/Sub Daemon, fields are set in the xGwa.PSDaemon MQ control block to track its progress. Inadequate checking of these fields results in it being possible for a Pub/Sub subtask to start before the Pub/Sub Daemon has finished its startup processing. These fields will be cleared during shutdown of the Pub/Sub daemon. The subtasks reference these fields unconditionally and without adequate serialisation, which may lead to them terminating with an ABEND0C4.
Problem conclusion
The serialisation has been improved to remove these timing windows during termination of the Pub/Sub daemon.
Temporary fix
Comments
APAR Information
APAR number
PH23564
Reported component name
IBM MQ Z/OS V9
Reported component ID
5655MQ900
Reported release
100
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2020-03-21
Closed date
2021-05-17
Last modified date
2021-06-02
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UI75425 UI75426
Modules/Macros
CSQXFCTL
Fix information
Fixed component name
IBM MQ Z/OS V9
Fixed component ID
5655MQ900
Applicable component levels
Fix is available
Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.
[{"Line of Business":{"code":"LOB45","label":"Automation"},"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SSYHRD","label":"IBM MQ"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"100"}]
Document Information
Modified date:
03 June 2021