IZ42988: SIGSEGV IN PTHREAD_KILL CALLED FROM XCSREQUESTMUTEXSEMFULL

WebSphere MQ V6.0 Fix Pack 6.0.2.7
WebSphere MQ 6.0 for HP OpenVMS Alpha and Itanium - Fix Pack 6.0.2.7
WebSphere MQ 6.0 for HP OpenVMS Alpha and Itanium - Fix Pack 6.0.2.10 (FP03)

APAR status

• Closed as program error.

Error description

• SIGSEGV in pthread_kill called from xcsRequestMutexSemFull
  

Local fix

Problem summary

• ****************************************************************
  USERS AFFECTED:
  This problem could hypothetically affect any user on Linux
  using the MQCNO_HANDLE_SHARE_BLOCK or
  MQCNO_HANDLE_SHARE_NOBLOCK. Note that the MQJMS java/JMS
  bindings use these options, even if the customers applications
  do not use the options directly.
  
  Platforms affected:
  Linux (Power),Linux (s390x),Linux (x86),Linux (x86-64),
  Linux (zSeries)
  
  ****************************************************************
  PROBLEM SUMMARY:
  After the queue manager has been waiting for a while for a lock
  then if the current lock owner is in the same process as the
  waiter the pthread_kill function is used to send signal 0
  to the owning thread. The return value from this function
  allows the lock waiter to check that the owner is still alive
  and to inherit the lock if that is not the case.
  Due to a timing/locking condition related to
  MQCNO_HANDLE_SHARE_BLOCK/MQCNO_HANDLE_SHARE_NO_BLOCK where the
  lock ownership ended while the waiter was taking this action
  then an invalid pthread_t value was passed to the pthread_kill
  function which then caused the SIGSEGV.
  

Problem conclusion

• A check was added to cater for the possibility of the pthread_t
  becoming invalid when the health check on the lock owner
  is performed.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
                     v6.0
  Platform           Fix Pack 6.0.2.7
  --------           --------------------
  Linux (x86)        U822325
  Linux (x86-64)     U822358
  Linux (zSeries)    U822329
  Linux (Power)      U822327
  Linux (s390x)      U822357
  
  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

• R600 PSY

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