A fix is available
APAR status
Closed as program error.
Error description
Development finds that a follow on ABEND0C1 can occur. In this APAR's case a preceding ABEND5C6 - 00E70033 abend for the full semaphore table was on a dispatcher PubSub daemon thread, which resulted in recovery in CSQXDISP getting control. Recovery retried to entry point CSQXRRCF in CSQXRRCX. This called fxxCleanThread to do cleanup for the daemon process. The problem is that the linkage to fxxCleanThread from CSQXRRCX is incorrect. This resulted in the return address not being set and none of the registers being saved on entry to the function. Once fxxCleanThread tried to return to CSQXRRCX it branched to low core and abended S0C1.
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: All users of IBM MQ for z/OS Version 9 * * Release 4 Modification 0. * **************************************************************** * PROBLEM DESCRIPTION: An ABEND0C1 may occur during recovery * * on a dispatcher publish/subscribe * * daemon thread. * **************************************************************** Following an abend on a publish/subscribe daemon thread, a subsequent ABEND0C1 may occur. The issue arises due to incorrect function linkage specified during the dispatcher recovery routine, preventing proper register handling and returning to the caller.
Problem conclusion
The correct function linkage has been specified during the recovery of the ABEND0C1.
Temporary fix
Comments
APAR Information
APAR number
PH67668
Reported component name
IBM MQ Z/OS V9
Reported component ID
5655MQ900
Reported release
CD0
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2025-08-06
Closed date
2025-11-13
Last modified date
2026-02-01
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UO05765
Modules/Macros
CSQXRRCX
Fix information
Fixed component name
IBM MQ Z/OS V9
Fixed component ID
5655MQ900
Applicable component levels
R400 PSY UO05765
UP26/01/10 P F601
Fix is available
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Document Information
Modified date:
01 February 2026