PH61201: CICS REGION HANG, DEADLY EMBRACE WITH TWO TASK, XMLOCK AND DUSYSDMP LOCKS

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Your CICS region hangs with two tasks in a deadly embrace. One
  task owns the XMLOCK but wants the DUSYSDMP lock, while another
  task owns the DUSYSDMP lock but wants the XMLOCK. Neither task
  can proceed. Often these are a CEMT transaction and the CICS TCP
  task, tranid CSTP.
  
  Other tasks will eventually backup behind this deadly embrace,
  and may cause other symptoms as well. In some instances, the
  CPSM MAS agent tasks may issue a message similar to this:
  .
  EYUCT0105E  Transport Services control block shortage has
  occurred.
  .
  This is because the CPSM MAS agent tasks in the region can not
  run as they are also stuck behind the deadly embrace. This is
  not a CPSM problem, but rather CPSM is a victim here.
  .
  These are the same symptoms as PH58961 - but the cause is
  different.
  

Local fix

• Cycle CICS
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All CICS users.                              *
  ****************************************************************
  * PROBLEM DESCRIPTION: CEMT or EXEC CICS SET SYDUMPCODE        *
  *                      can cause CICS to stall with two        *
  *                      tasks in a deadly embrace.              *
  ****************************************************************
  A CICS task is processing CEMT or EXEC CICS SET SYDUMPCODE when
  another task causes a message to be issued.
  CICS suffers a locking problem between the two tasks.
  Each task contends for the XMLOCK and DUSYSDMP locks.
  The CICS tasks stall in SUSPENDs for the locks.
  If a dump is taken then it will show two tasks in a deadlock.
  One of then will have issued a SET SYDUMPCODE command.
  

Problem conclusion

• CICS SET SYDUMPCODE processing has been changed to prevent the
  need for the XMLOCK to be used.
  

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:

  UI97768 UI97769

Modules/Macros

• DFHMEIN
  

Fix information

• Fixed component name

  CICS TS Z/OS V6

• Fixed component ID

  5655YA100

Applicable component levels

• R400 PSY UI97769

     UP24/07/25 P F407 ¢

• R500 PSY UI97768

     UP24/07/26 P F407 ¢

Fix is available

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