PM89391: THREAD DOING AUTOBIND MAY HANG IN DSNTABA AFTER BEING CANCELLED

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Thread doing Autobind may hang in DSNTABA after being cancelled
  .
  SKPT
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users of DB2 for zOS                     *
  *                                                              *
  ****************************************************************
  * PROBLEM DESCRIPTION: An agent may become hung in CSECT       *
  *                      DSNTABA if a -CANCEL THREAD command is  *
  *                      issued for that agent while it was      *
  *                      holding an IRLM lock.                   *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  When a -CANCEL THREAD command is issued for an agent that is
  holding a SKPT p-lock, EDM abort processing will save that
  SKPT p-lock on a global EDM chain to be cleaned up during IRLM
  synchronization that occurs during general agent abort/
  deallocation processing.  Any new agent that requires the same
  SKPT p-lock may also try to purge SKPT p-locks on the global
  EDM chain that are leftover from previous threads.
  
  This leads to a race condition between IRLM synchronization
  process for a cancelled thread an a new DB2 agent that may be
  interested in the SKPT p-lock.  If the latter wins the race,
  IRLM synchronization processing in CSECT DSNTABA will
  incorrectly suspend waiting for a system task that its scheduled
  to free the lock.  This will never occur since this system task
  will not find this lock, resulting in a indefinite hang in the
  CSECT DSNTABA.
  
  This race condition only exists when SKPT p-lock is involved.
  

Problem conclusion

• Remove the race condition by having EDM cancel processing use
  an agent specific chain to save those SKPT p-locks that need to
  be freed during the abort/deallocation process.
  

Temporary fix

• *********
  * HIPER *
  *********
  

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

  UK97873 UK97874 UK97875

Modules/Macros

• DSNGEELC DSNGEFLC DSNTABA  DSNTADL
  

Fix information

• Fixed component name

  DB2 OS/390 & Z/

• Fixed component ID

  5740XYR00

Applicable component levels

• RA10 PSY UK97873

     UP13/10/10 P F310 ½

• RB10 PSY UK97874

     UP13/10/10 P F310 ½

• R910 PSY UK97875

     UP13/10/11 P F310 ½

Fix is available

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