IV25859: Probe ZC045010 and XC332063 FDCs for application using Shared HCONNs with Linux Threads at MQ 6.0.2.11 or later.

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

• Probe ZC045010 FDCs from function zcpError and probe XC332063
  FDCs from xlsWaitEvent, together with those FDCs identifying
  that the ThreadingModel is LinuxThreads, is a good indicator of
  encountering this issue.
  
  The issue also requires that the application reporting the probe
  XC332063 FDCs is using shared HCONNs. This is indicated if the
  FDC Trace History shows references to zutAquireSharedPCD and
  zutReleaseSharedPCD functions.
  

Local fix

• If there is no specific need, avoid the use of the Linux
  threading model by removing the LD_ASSUME_KERNEL=2.4.19
  environment variable setting for the queue manager and
  applications.
  

Problem summary

• ****************************************************************
  USERS AFFECTED:
  You may be exposed to this issue if you have ALL of the
  following: using MQ V6.0.2.11 or later MQ V6 fixpacks; using
  the Linux thread model (because you have set environment
  variable LD_ASSUME_KERNEL=2.4.19); and you have applications
  using shared HCONNs.
  
  Platforms affected:
  Linux (Power),Linux (s390x),Linux (x86),Linux (x86-64),
  Linux (zSeries)
  
  ****************************************************************
  PROBLEM SUMMARY:
  Use of Linux threads causes particular difficulties for the
  queue manager checking the liveness of processes. The queue
  manager must be particularly careful to ensure the check is made
  against the process id, not against the Linux thread-process.
  
  Unfortunately, some cleanup checking introduced at MQ 6.0.2.11
  mistakenly did use the thread-process, causing an issue in the
  circumstance where the connecting application used a shared
  HCONN.
  

Problem conclusion

• The cleanup checking was corrected to avoid making a liveness
  check against a Linux thread-process.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
                     v6.0
  Platform           Fix Pack 6.0.2.12
  --------           --------------------
  Linux (x86)        U842210
  Linux (x86-64)     U842215
  Linux (zSeries)    U842211
  Linux (Power)      U842212
  Linux (s390x)      U842214
  
  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 LIN X86 V6

• Fixed component ID

  5724H7204

Applicable component levels

• R602 PSY

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