A fix is available
APAR status
Closed as program error.
Error description
After concurrent issues within other system applications it is necessary to issue a STOP against MQ. The queue manager does not quiesce. Subsequently, z/OS CANCEL and FORCE commands issued against the MQ subsystem also are unable to terminate it, resulting in a necessary IPL. The SRM state of MQ is left as "CANCEL IN PROGRESS", as MQ continues to hold an ENQueue against resource SYSZCSQ3 ERLYOLRH. . Additional keywords: ACECHNA loop . After this APAR is applied, if a loop is detected, the queue manager terminates with CSQV086E QUEUE MANAGER ABNORMAL TERMINATION REASON=00F30908 and IEF450I ABEND=S6C6 U0000 REASON=00F30908
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: All users of IBM MQ for z/OS Version 9 * * Release 0 Modification 0, Release 1 * * Modification 0 and Release 2 Modification 0. * **************************************************************** * PROBLEM DESCRIPTION: Various problems encountered when an * * application connected to a queue * * manager are terminated abnormally (for * * example, Cancel, Force, Memterm). * * Symptoms can include: * * - High CPU usage in the application, * * queue manager, or MASTER address * * space * * - Application and/or Queue manager * * address spaces do not end, and cannot * * be canceled or forced * * - Other applications hang waiting for * * resources held by MQ * * In extreme cases an IPL is required to * * resolve the problem. * **************************************************************** A loop was introduced into the VLCAAACE chain for an application address space. The cause of the loop is unknown. When the application goes through end of memory processing, or when the queue manager is abnormally terminated, the VLCAAACE chain(s) are scanned for any ACEs that require cleaning up. However due to the loop in the chain, this processing (which can occur in the application address space, queue manager address space, or MASTER (0001) address space, began looping indefinitely.
Problem conclusion
MQ End of Memory and Termination processing are changed to detect unexpected loops in the VLCAAACE chains. In the event of a loop being found, the queue manager is terminated abnormally, preventing the error impacting on other applications/services on the system.
Temporary fix
Comments
APAR Information
APAR number
PH27803
Reported component name
IBM MQ Z/OS V9
Reported component ID
5655MQ900
Reported release
100
Status
CLOSED PER
PE
NoPE
HIPER
YesHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2020-07-23
Closed date
2020-12-17
Last modified date
2023-09-29
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UI72157 UI72158 UI73202
Modules/Macros
CSQ3SSI1 CSQ3SSI2 CSQVATRM
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:
29 September 2023