IT27611: POTENTIAL FOR MT_EX_OS CATCH TO LEAVE SCB->THREADLATCH MUTEX LOCKED

APAR status

• Closed as program error.

Error description

• mt_prscblst had mt_ex_catch that only handles unlock of
  ses_seslatch, but can lock scb->threadlatch temporarily.
  Also, mt_nxtscb temporary (and unnecessarily locks
  scb->threadlatch), but doesn't check the returned scb for
  SCB_CLEANUP in all cases.
  
  For sake of searchability, addiing an example of what the
  scb->threadlatch looks like in an onstat -g lmx
  output since the mutex has a unique name, scbthd.  This
  particular example shows the holder 858 waiting
  on itself for the mutex which is what can happen when this
  defect surfaces.
  
  Locked mutexes:
  mid         addr                     name               holder
  lkcnt  waiter   waittime
  14737    700000575a32028  scbthd             858      0      858
  3573
  17          70000001f730038  session            858      0
  33       3573
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * Users of IDS prior to 12.10.xC13.                            *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * Potential for MT_EX_OS catch to leave scb->threadlatch mutex *
  * locked.                                                      *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Upgrade to Informix Server 12.10.xC13 or 14.10.xC1.          *
  ****************************************************************
  

Problem conclusion

• Fixed in IDS 12.10.xC13 and 14.10.xC1.
  

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

  INFORMIX SERVER

• Fixed component ID

  5725A3900

Applicable component levels