A fix is available
APAR status
Closed as program error.
Error description
If a shared memory set is unavailable then the queue manager may enter an infinite loop when using CHLAUTH administration commands. If this problem occurs then the IBM MQ amqzlaa0 process will be seen to use a large amount of CPU. Extract from a failure data capture (FDC) record that was generated as a result of the issue: WebSphere MQ First Failure Symptom Report ========================================= Probe Id :- XY388255 Component :- xcsConnectSharedMemSet Probe Description :- AMQ6109: An internal WebSphere MQ error has occurred. ---------------------------------------------------- MQM Function Stack zlaMainThread zlaProcessMessage zlaProcessSPIRequest zlaSPIKernel zsqSPIKernel kpiGeneric kqiSetChlAuthMap rsxAccessCache xcsConnectSharedMemSet xcsFFST
Local fix
Restarting the queue manager will work around the problem. It may be necessary to end the queue manager with the -p (pre-emptive) option.
Problem summary
**************************************************************** USERS AFFECTED: Users who remove IBM MQ shared memory resources may be affected by this issue. Platforms affected: MultiPlatform **************************************************************** PROBLEM DESCRIPTION: If a shared memory segment belonging to IBM MQ was removed when MQ is running then the amqzlaa0 process may have entered an infinite loop as it attempts to access this segment.
Problem conclusion
The IBM MQ code was modified so that it does not continually attempt to access the shared memory resource if it does not exist. Instead, an FDC record with probe RM951010 is generated and the following error will be seen when using CHLAUTH administration commands: SET CHLAUTH('*') TYPE(BLOCKADDR) ADDRLIST('xxx.xxx.xxx.xxx') 1 : SET CHLAUTH('*') TYPE(BLOCKADDR) ADDRLIST('xxx.xxx.xxx.xxx') AMQ9774: Error accessing the Channel authentication table The queue manager should be restarted as soon as possible. It is advisable to check whether the ipcrm (or host OS equivalent) command had recently been run by an administrator or a script, as MQ IPC resources should not be removed while the queue manager is running. --------------------------------------------------------------- The fix is targeted for delivery in the following PTFs: Version Maintenance Level v7.5 7.5.0.9 v8.0 8.0.0.11 v9.0 LTS 9.0.0.6 v9.1 CD 9.1.1 v9.1 LTS 9.1.0.1 The latest available maintenance can be obtained from 'WebSphere MQ Recommended Fixes' http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006037 If the maintenance level is not yet available information on its planned availability can be found in 'WebSphere MQ Planned Maintenance Release Dates' http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006309 ---------------------------------------------------------------
Temporary fix
Comments
APAR Information
APAR number
IT24878
Reported component name
WEBSPHERE MQ 7.
Reported component ID
5724H7240
Reported release
750
Status
CLOSED PER
PE
NoPE
HIPER
YesHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2018-04-26
Closed date
2018-07-05
Last modified date
2018-07-12
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
Fix information
Fixed component name
WEBSPHERE MQ 7.
Fixed component ID
5724H7240
Applicable component levels
R750 PSY
UP
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Document Information
Modified date:
30 August 2021