A fix is available
APAR status
Closed as program error.
Error description
The customer is running WebSphere MQ for z/OS V8.0 when QMGR CSQ9MSTR abended with the following: . TITLE: CSQ1,ABN=5C6-00E50002,U=SYSOPR ,C=W9700.800.ASMC- CSQVUNLX,M=CSQVLFRR,LOC=CSQMLPLM.CSQMREF1+00000B2E . Looking at the PSW 077C1001 236E7466, the actual abend 5C6-00E50002 is produced in Csect CSQVXUL0 (BASE) at offset x'6B4'. The '00E50002'X means, "UNLATCH REQUEST AND LATCH NOT OWNED BY REQUESTING EB". According to the code, the following are contained in the regs at time of abend: . R2 = XCLASSNO 0000002B (LPVT) GR3 = XLTCHPTR 59F7F768 . MSTR trace is enabled but only contains a few enteries for the EB 20AB0F18 (212.MMCLTRX). I found APARs PI19991/UI20637 and PI47734/UI30746 that mentioned 00E50002 but did match this module and offset. The APARs do appear to be applied. . The change team reviewed the dump and determined the abend occurs due to an IVSA being reused while still in use by CSQMREF1. Trace shows that CSQICDSQ was called due to the deletion of queue LG62SD03278C8C0905DA9 on another qmgr in the qsg. CSQICDSQ called CSQMCSQF to close the connection to the queue, and this queued the close request to the structure task. However there was a significant delay (several seconds) before this request completed but it's not clear from the trace what caused this delay. While this request was pending the list transition exit detected a transition for this queue and CSQMREF1 was called to process it. CSQMREF1 suspended waiting for the IVSA latch, which was held by the deleting task. When the close request completed, CSQMCSQF released the latch and CSQMREF1 obtained it. CSQICDSQ then released the IVSA, which contains this latch, and the IVSA was then used by another queue. When CSQMREF1 subsequently attempted to release the IVSA latch, it abended because the latch no longer appeared to be held (due to it now being associated with a different queue). It appears that there is insufficient serialisation between list transitions and CSQICDSQ. . Additional Symptoms: ABEND S0C4 ABN=0C4-00000011 CSQERCAT+000009FE
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: All users of WebSphere MQ for z/OS Version 8 * * Release 0 Modification 0. * **************************************************************** * PROBLEM DESCRIPTION: Various abends occur when a shared * * queue is deleted on a different queue * * manager in the queue sharing group, and * * the local queue manager is processing a * * list transition for the queue. * * * * Symptoms can include: * * - Abend 0C4 in CSQMLTR0 * * - Abend 5C6-00C5101A in CSQEBMON * * - Abend 5C6-00D40025 in CSQMLTR0 * * - Abend 5C6-00E50002 in CSQMREF1 * * The abends are followed by abnormal * * queue manager termination 6C6 with * * REASON=00E50702 * **************************************************************** * RECOMMENDATION: * **************************************************************** Insufficient serialisation between list transition exit processing for a shared queue and shared queue deletion processing can allow CSQICDSQ to free the IVSA for a shared queue that has just been deleted on another queue manager in the queue sharing group, while a list transition is being processed for that shared queue. Depending on the type of list transition being processed, and how quickly the freed IVSA is reused by another queue, this can lead to several different abends occurring in list transition processing. The abnormal termination of the SRB processing the list transition is unexpected, and results in the queue manager terminating abnormally.
Problem conclusion
The serialisation between shared queue deletion and list transition processing is improved to prevent the IVSA being freed while still being used by list transition processing. 000Y CSQELTRX CSQICDSQ CSQIEXP2 CSQMLTRX CSQMLTR0
Temporary fix
********* * HIPER * *********
Comments
APAR Information
APAR number
PI56990
Reported component name
WMQ Z/OS 8
Reported component ID
5655W9700
Reported release
000
Status
CLOSED PER
PE
NoPE
HIPER
YesHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2016-02-10
Closed date
2016-08-26
Last modified date
2016-10-03
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UI40384
Modules/Macros
CSQELTRX CSQICDSQ CSQIEXP2 CSQMLTRX CSQMLTR0
Fix information
Fixed component name
WMQ Z/OS 8
Fixed component ID
5655W9700
Applicable component levels
R000 PSY UI40384
UP16/09/20 P F609 ¢
Fix is available
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Document Information
Modified date:
03 October 2016