IV09149: A corrupt channel synchronization file may cause channel code to enter an infinite loop without an obvious error report

WebSphere MQ V7.0 Fix Pack 7.0.1.8
WebSphere MQ V7.0.1 for i5/OS Fix Pack 7.0.1.8
Fix Pack 7.1.0.1 for WebSphere MQ V7.1
WebSphere MQ V7.1 for i5/OS Fix Pack 7.1.0.1
WebSphere MQ v7.0.1.8 Hypervisor for AIX
WebSphere MQ v7.0.1.8 Hypervisor for RHEL
WebSphere MQ V6.0 Fix Pack 6.0.2.12
WebSphere MQ V6.0 for iSeries Fix Pack 6.0.2.12
WebSphere MQ 6.0 for HP OpenVMS Alpha and Itanium - Fix Pack 6.0.2.12

APAR status

• Closed as program error.

Error description

• The channel synchronization file AMQRSYNA.DAT is located within
  the queue manager data area. This file is used as part of the
  channel synchronization mechanism. If a queue manager process
  is killed whilst this file is being updated, then as with any
  file, this action may corrupt it.
  
  A particular corruption would cause records within that file to
  be self-linked, resulting in an infinite lookup within channel
  processes.
  
  In that circumstance, it is possible that channels would fail
  to function and an FDC similar to the following could be
  written periodically (perhaps every 20 minutes). This shows an
  interminable wait for a lock within the "getkey" function.
  
  FDC file generated:
  LVLS              :- 7.0.1.2
  Probe Id          :- XC307070
  Application Name  :- MQM
  Component         :- xlsRequestMutex
  Program Name      :- amqrmppa
  Major Errorcode   :- xecL_W_LONG_LOCK_WAIT
  Probe Type        :- MSGAMQ6150
  Probe Severity    :- 3
  Probe Description :- AMQ6150: WebSphere MQ semaphore is busy.
  Comment1          :- OwningProcess(4283) Status(ACTIVE)
  Comment2          :- S (sleeping)
  MQM Function Stack
  rriCallerEntry
  rriCheckSync
  rriAccessSync
  rrxReadSync
  getkey
  xcsRequestMutexSem
  xlsRequestMutex
  xcsFFST
  

Local fix

• If linear logging is used, the command  "rcrmqobj -m QMGRNAME -t
  syncfile" can be used to recover AMQRSYNA.DAT to a good state.
  

Problem summary

• ****************************************************************
  USERS AFFECTED:
  Users affected are those who have a channel synchronization
  file (AMQRSYNA.DAT) that becomes corrupted, possibly due to
  killing queue manager processes whilst it is being updated.
  
  Platforms affected:
  All Distributed (iSeries, all Unix and Windows)
  ****************************************************************
  PROBLEM SUMMARY:
  This APAR follows on from an earlier APAR IZ95863 which
  introduced a particular, specific, check to detect looping when
  processing the AMQRSYNA.DAT file. The aim with this new APAR is
  to add a check to detect any kind of corruption that could lead
  to looping.
  
  If the AMQRSYNA.DAT file is found to be corrupted then it
  should be recoverable; it may need to be manually removed first
  during a queue manager recycle. This would normally be
  undertaken through advice from IBM Service, and care should be
  taken to preserve all evidence in the event that this matter
  needs to be investigated further.
  

Problem conclusion

• A general check for badly-linked records has been added to the
  code that manages the channel synchronization file
  AMQRSYNA.DAT. This check will report, via FDCs, that the file is
  corrupted if a badly-linked record is encountered.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
                     v6.0
  Platform           Fix Pack 6.0.2.12
  --------           --------------------
  Windows            U200331
  AIX                U842074
  HP-UX (PA-RISC)    U842208
  HP-UX (Itanium)    U842213
  Solaris (SPARC)    U842209
  Solaris (x86-64)   U842216
  iSeries            tbc_p600_0_2_12
  Linux (x86)        U842210
  Linux (x86-64)     U842215
  Linux (zSeries)    U842211
  Linux (Power)      U842212
  Linux (s390x)      U842214
  
                     v7.0
  Platform           Fix Pack 7.0.1.8
  --------           --------------------
  Windows            U200335
  AIX                U845856
  HP-UX (PA-RISC)    U847965
  HP-UX (Itanium)    U847970
  Solaris (SPARC)    U847966
  Solaris (x86-64)   U847972
  iSeries            7.0.1.8
  Linux (x86)        U847967
  Linux (x86-64)     U847971
  Linux (zSeries)    U847968
  Linux (Power)      U847969
  
                     v7.1
  Platform           Fix Pack 7.1.0.1
  --------           --------------------
  Windows            U200338
  AIX                U849732
  HP-UX (Itanium)    U850307
  Solaris (SPARC)    U850303
  Solaris (x86-64)   U850309
  iSeries            7.1.0.1
  Linux (x86)        U850304
  Linux (x86-64)     U850308
  Linux (zSeries)    U850305
  Linux (Power)      U850306
  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 is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  WMQ AIX V7

• Fixed component ID

  5724H7221

Applicable component levels

• R701 PSY

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