A fix is available
APAR status
Closed as program error.
Error description
An application is designed to execute ATTACH and DETACH macros. When DETACH is executed, abend 13E and 602 happened. The abend 602 occurred in CSQM1P1W when trying to do a cross-memory post to a getter's handle with post code MQEC_WAIT_INTERVAL_EXPIRED. This happens when the WaitInterval on an MQGET was exceeded. The abend is occurring because the ASCB address being passed to the POST is 0. The ASCB is obtained from the ASCE MQ control block, but the ASCE being used isn't marked as allocated and thus doesn't contain the correct ASCB address. The outstanding get wait timers are usually cleaned up during end of task (EOT) for the TCB, but this hasn't happen. CSQ3RRSM was called for context manager EOT and issued an abort of the RRS transaction. This results in an SRB being scheduled to CSQRUCA3 in the QMGR to complete the abort processing and the requesting TCB suspending awaiting completion of this request. While the TCB was suspended, it was abended S013E by the TCB being detached. This results in subsequent cleanup processing in CSQ3RRSM being skipped. Recovery for CSQ3RRSM removes the ACE from the VLCAAACE chain, which means that later end of memory (EOM) processing for the address space doesn't deallocate the agent and cancel the get wait timer. additional keyword ABEND602
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: All users of IBM MQ for z/OS Version 9 * * Release 2 Modification 0 and * * Release 3 Modification 0. * **************************************************************** * PROBLEM DESCRIPTION: Various problems can occur when an * * application detaches a TCB associated * * with an RRS context (including the * * native context) while the TCB is * * already ending. * * Symptoms can include: * * - abend 602 in CSQM1P1W * * - unclosed handles on a queue, * * preventing e.g. CLEAR QUEUE * * - abend 0C4 in CSQVEUS2, followed * * by abnormal queue manager * * termination S6C6 * * - 0C4 abends recorded in logrec during * * recovery processing * * - critical queue manager threads * * hanging, leading to unpredictable * * results * **************************************************************** An application with TCBs that were/had been connected to MQ issued a DETACH macro to abend the TCBs. When the TCB is already ending, and there is MQ work associated with the TCB's current or native RRS context, MQ's end context exit is called during end of task processing. If this exit is then interrupted by the DETACH macro, errors in recovery processing can result in symptoms such as unexpected abends, or object handles not being correctly closed. If the context ACE is left in a must complete state (for example holding one or more latches), the queue manager should be terminated, however this state is not detected, potentially resulting in critical queue manager processing hanging.
Problem conclusion
Recovery processing for the MQ RRS End Context Exit is changed to close open handles associated with the context ACE for the ending context, and to improve serialisation with local memory termination processing. The MQ RRS exits will also terminate the queue manager abnormally S6C6 if the context ACE is found to have unreleased latches at the end of normal or recovery processing to protect the queue manager's integrity.
Temporary fix
Comments
APAR Information
APAR number
PH58940
Reported component name
IBM MQ Z/OS V9
Reported component ID
5655MQ900
Reported release
200
Status
CLOSED PER
PE
NoPE
HIPER
YesHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2023-12-27
Closed date
2024-02-08
Last modified date
2024-03-03
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UI95607 UI95608
Modules/Macros
CSQ3RRSF CSQ3RRSM CSQ3RRXF CSQ3TRAC CSQARIB CSQVASTM
Fix information
Fixed component name
IBM MQ Z/OS V9
Fixed component ID
5655MQ900
Applicable component levels
Fix is available
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Document Information
Modified date:
04 April 2024