IT36414: FDC with probe ID XC130003 is generated when an IBM MQ C client tries to connect

APAR status

• Closed as program error.

Error description

• When an IBM MQ C client application that is configured to use a
  channel exit attempts to connect to a IBM MQ queue manager using
  the MQCONNX call and provides an incorrect password, the
  following FDC is generated:
  
  Probe Id          :- XC130003
  Component         :- xehExceptionHandler
  Program Name      :- amqscnxc
  Thread            :- 2    ChannelReceive
  Probe Type        :- HALT6109
  Comment1          :- SIGSEGV: address not mapped(0x40)
  ------------------------------------------------------------
  O/S Call Stack for current thread
  /opt/mqm/lib64/libmqe_r.so(+0x3cd69e)[0x7fd65385069e]
  /opt/mqm/lib64/libmqe_r.so(+0x3e7e4a)[0x7fd65386ae4a]
  /opt/mqm/lib64/libmqe_r.so(+0x3e6cb7)[0x7fd653869cb7]
  /opt/mqm/lib64/libmqe_r.so(+0x3e9e97)[0x7fd65386ce97]
  /opt/mqm/lib64/libmqe_r.so(+0x3e04d5)[0x7fd6538634d5]
  /usr/lib64/libpthread.so.0(+0xf370)[0x7fd654a0e370]
  /usr/lib64/libpthread.so.0(__pthread_mutex_trylock+0x13)[0x7fd65
  4a08d63]
  /opt/mqm/lib64/libmqe_r.so(+0x3efe52)[0x7fd653872e52]
  /opt/mqm/lib64/libmqe_r.so(+0x2164d0)[0x7fd6536994d0]
  /opt/mqm/lib64/libmqe_r.so(+0x217086)[0x7fd65369a086]
  /opt/mqm/lib64/libmqe_r.so(+0x220709)[0x7fd6536a3709]
  /opt/mqm/lib64/libmqe_r.so(+0x2235b3)[0x7fd6536a65b3]
  /opt/mqm/lib64/libmqe_r.so(+0x223ab1)[0x7fd6536a6ab1]
  /opt/mqm/lib64/libmqe_r.so(+0x4417ee)[0x7fd6538c47ee]
  /usr/lib64/libpthread.so.0(+0x7dc5)[0x7fd654a06dc5]
  /usr/lib64/libc.so.6(clone+0x6d)[0x7fd65453176d]
  MQM Function Stack
  cciReceiveThread
  ccxReceiveThreadFn
  cciProcessOne
  cciProcessUserData
  cciProcessSyncRcv
  xcsRequestThreadMutexSem
  xcsFFST
  

Local fix

Problem summary

• ****************************************************************
  USERS AFFECTED:
  Users of IBM MQ C client channel security exits may be affected
  by this issue.
  
  
  Platforms affected:
  MultiPlatform
  
  ****************************************************************
  PROBLEM DESCRIPTION:
  A race condition between between MQDISC processing and
  processing an MQXCC_CLOSE_CHANNEL response from an exit causes
  memory to be accessed which had already been freed.  This
  results in a SIGSEGV in the IBM MQ C client application.
  

Problem conclusion

• The code has been corrected to remove the possibility of the
  race condition occurring.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
  Version    Maintenance Level
  v9.1 LTS   9.1.0.12
  v9.x CD    9.1.5
  
  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

  IBM MQ BASE MP

• Fixed component ID

  5724H7271

Applicable component levels