A fix is available
APAR status
Closed as program error.
Error description
ACE and EB control blocks remain allocated after the context associated with them have already ended. The orphaned control blocks are allocated from subpools of storage used by WebSphere MQ and so can still be freed if the QMGR is shutdown.
Local fix
Recycle queue manager
Problem summary
**************************************************************** * USERS AFFECTED: All users of WebSphere MQ for z/OS Version 7 * * Release 0 Modification 1 and Release 1 * * Modification 0. * **************************************************************** * PROBLEM DESCRIPTION: After applying PTF UK79818 (for Version * * 701) or UK81712 (for Version 710), a * * leak of ACE/EB control blocks can occur * * when an application task using WMQ * * private contexts ends without first * * ending all the contexts. This can * * happen due to a normal end without * * appropriate cleanup, or due to an * * application abend. * **************************************************************** * RECOMMENDATION: * **************************************************************** Various changes were made in PM64200 (for V701) and PM67446 (for V710), corresponding to the above PTFs, helping to ensure that RRS threads do not go through deferred end-of-task if end-context has taken place or deferred end-context has been scheduled (or vice versa). This code added extra serialization using the CCBDENDS flag to ensure that ACE/EBs were not cleaned up by one process while queued for cleanup by another. Following APAR PM64200 and PM67446 a problem can be seen during an abend or a normal end (without ending the context) of an application that creates a private context. In this case a private context is scheduled for deferred end-context processing, which sets CCBDENDS to ensure that no-one else tries to deal with it. When RRS is called to end the context during processing of the deferred end-context, RRS drives CSQ3RRSX exit for CTX_END_CONTEXT_EXIT. CSQ3RRSX finds that CCBDENDS is set on and does not free the ACE/EB for the context and the ACE/EB gets orphaned.
Problem conclusion
The code has been changed to reset CCBDENDS prior to calling RRS to end-context. 010Y 100Y CSQMCTXE
Temporary fix
Comments
APAR Information
APAR number
PM77017
Reported component name
WMQ Z/OS V7
Reported component ID
5655R3600
Reported release
010
Status
CLOSED PER
PE
YesPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2012-11-13
Closed date
2012-12-21
Last modified date
2013-03-04
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UK90568 UK90569
Modules/Macros
CSQMCTXE
Fix information
Fixed component name
WMQ Z/OS V7
Fixed component ID
5655R3600
Applicable component levels
Fix is available
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Document Information
Modified date:
04 March 2013