IT37134: Potential for SIGSEGV from a null pointer in xcsRequestMutexSemFn

APAR status

• Closed as program error.

Error description

• The internal function xcsRequestMutexSemFn might make an invalid
  memory access if passed a null pointer, resulting in a failure
  data capture (FDC) record with probe ID XC130003  reporting a
  SIGSEGV.
  

Local fix

Problem summary

• ****************************************************************
  USERS AFFECTED:
  All users of MQ.
  
  
  Platforms affected:
  MultiPlatform
  
  ****************************************************************
  PROBLEM DESCRIPTION:
  After an upstream error, a null pointer was passed into
  xcsRequestMutexSemFn.  This caused a SIGSEGV within
  xcsRequestMutexSemFn, but it would have been better to detect
  the null pointer and write an FDC record, rather than the
  SIGSEGV.
  

Problem conclusion

• Defensive code has been added to xcsRequestMutexSemFn to ensure
  that a null pointer does not result in a SIGSEGV.  This does not
  fix the upstream problem, but prevents it causing an abend more
  severe than necessary.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
  Version    Maintenance Level
  v9.2 LTS   9.2.0.4
  v9.x CD    9.2.4
  
  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

  MQ APPL M2002 V

• Fixed component ID

  5737H4701

Applicable component levels