PH23250: DFHDS0002 CICSREGN A SEVERE ERROR (CODE X'0070') HAS OCCURRED IN MODULE DFHDSSR.

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• DFHDS0002 CICSREGN A severe error (code X'0070') has occurred
  in module DFHDSSR.
  
  This problem is occurs when a dozen or more
  tasks are waiting in a FCPSSUSP suspend, and one of these tasks
  is purged about the same time another task is releasing a
  string and resuming all the tasks that are waiting in the
  FCPSSUSP wait.
  
  So it looks like it is a race between the task
  that got purged, and the task that is doing the resuming. If
  the resume happens before the next suspend, all is well. If the
  resume happens after the next suspend, you get the
  problem.
  
  Additional Symptom(s) Search
  Keyword(s):
  

Local fix

• n/a
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All CICS users.                              *
  ****************************************************************
  * PROBLEM DESCRIPTION: DFHDS0002 A severe error (CODE X'0070') *
  *                      occurred in module DFHDSSR.             *
  ****************************************************************
  The problem was the result of a race condition between multiple
  transactions accessing CICS file control under open TCBs.
  A transaction suspended on a file string wait (FCPSSUSP) for a
  local VSAM file. Another transaction was completing its file
  request and began to process the chain of transactions waiting
  to be resumed, to let them acquire the strings they wanted. The
  chain of waiters to be resumed was removed from the FCT anchor
  under a shared lock for string manipulation. This lock was then
  released before the transactions were each called in turn to be
  resumed. Meanwhile, the original transaction was forcepurged
  and redispatched from its FCPSSUSP suspend. It acquired an
  exclusive lock to see if it was waiting for a string, but by
  this point the chain of waiters had been removed from the FCT
  prior to being resumed. This meant the original transaction did
  not find itself on the chain of waiters and so did not resume
  itself to the CICS dispatcher. The logic assumed another
  transaction must have performed the resume on its behalf in such
  a case. However, the iteration of the chain to resume all the
  transactions awaiting a string had yet to reach the original
  transaction's VSWA on the chain, before that transaction begun
  its forcepurge abend processing, and eventually called the
  CICS dispatcher to suspend as part of the abend. Since the
  transaction's DTA's SUSPEND_RESUME_AREA still showed purged and
  not reset, the dispatcher treated this as an invalid state
  transition since suspend cleanup work was still pending. It
  resulted in the DFHDS0002 abend and system dump.
  KEYWORDS: fct_string_head SUSP_CLEANUP_PENDING msgdfhds0002
            dfhds0002 ds0002 0002 ds
  

Problem conclusion

• DFHFCVS1 routine release_strings has been changed to maintain
  the shared string lock until any waiting transactions have
  been resumed. This prevents a purged waiter from incorrectly
  assuming that it is not awaiting a resume, since it requires
  the exclusive string lock to be able to make this determination.
  

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:

  UI69441 UI69442

Modules/Macros

• DFHFCVS
  

Fix information

• Fixed component name

  CICS TS Z/OS V5

• Fixed component ID

  5655Y0400

Applicable component levels

• R100 PSY UI69441

     UP20/05/15 P F005

• R200 PSY UI69442

     UP20/05/15 P F005

Fix is available

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