PH27326: DFHSM0002 SEVERE ERROR CODE 0316 IN MODULE DFHSMGF FREEMAINING AN IPIC BUFFER IS_BUFF

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• You are running CICS TS 5.4 and receive the following
  error message:
  DFHSM0002 A SEVERE ERROR (CODE X'0316') HAS OCCURRED
            IN MODULE DFHSMGF.
  Reviewing the dump at the time of this error shows the
  following exception trace:
  SM 0316 SMGF  *EXC* - Freemain_of_pages_not_owned_by_subpool -
                 FUNCTION(FREEMAIN)
                 ADDRESS(xxxxxxxx) REMARK(IS_BUFF)
  The address xxxxxxxx is already free at the time of the dump
  causing the exception.
  Here are the trace entries prior to the exception:
  
  IS 0900 ISZA  ENTRY - FUNCTION(FREE_ISSB)    ISSB_PTR(address)
  IS 0800 ISAL  ENTRY - FUNCTION(FREE_RECEIVE) ISSB_PTR(address
  SM 0301 SMGF  ENTRY - FUNCTION(FREEMAIN) ADDRESS(xxxxxxxx)
                REMARK(IS_BUFF))
  
  The failing task is associated with an IP interconnectivity-IPIC
  session and attempting to freemain an IS Buffer it used.
  
  
  Trace showed the issue where a task using this IS_BUFF xxxxxxxx,
  was in FREE_ISSB processing when it was suspended for the
  SMLOCK.
  While suspended, the client sent in more data, which was handled
  by the IPIC request/response receiver- tran CISR. It incorrectly
  used this buffer xxxxxxxx, before the FREE_ISSB processing had
  completed, resulting in a double freemain of the buffer.
  .
  Additional Symptoms: KIXREVDAM
  IPCONN TCPIPSERVICE
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All CICS users.                              *
  ****************************************************************
  * PROBLEM DESCRIPTION: CICS receives a request over IPIC and   *
  *                      runs a mirror task which issues message *
  *                      DFHSM0002.                              *
  ****************************************************************
  A client sends in a DPL request with a channel over an IPIC
  connection.  There is more than 64k of data in the channel.
  
  When the mirror task that processed this request terminates,
  DFHISAL is called to free the IS_BUFF buffers that were used by
  this IPIC session (ISSB).  The FREEMAIN of one of the buffers
  get suspended waiting for the SMLOCK.  This buffer had the
  ISSB_REUSABLE flag set on.
  
  While the mirror task was suspended a second request was sent in
  by the client using the same session.  CISR needs to receive the
  request into a buffer.  It finds an IS_BUFF that has the
  ISSB_REUSABLE flag set on and uses it.  This is the same IS_BUFF
  that DFHISAL was in the process of freeing.
  
  The mirror task eventually obtains the SMLOCK and freemains the
  IS_BUFF.  A new mirror task is then started to process the
  second request.  The received data is in the, now freed,
  IS_BUFF that CISR had reused.  When this second mirror task
  completes it tries to freemain the IS_BUFF again.  This causes
  message DFHSM0002 code(x'0316') to be issued and a dump taken.
  
  Additional keywords: FREE_ISSB IS0002
  

Problem conclusion

• DFHISAL has been changed to clear the ISSB_REUSABLE flag before
  the call to FREEMAIN the IS_BUFF.
  

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:

  UI72239 UI72240 UI72241

Modules/Macros

• DFHISAL
  

Fix information

• Fixed component name

  CICS TS Z/OS V5

• Fixed component ID

  5655Y0400

Applicable component levels

• R100 PSY UI72241

     UP20/10/28 P F010

• R200 PSY UI72240

     UP20/10/27 P F010

• R300 PSY UI72239

     UP20/10/27 P F010

Fix is available

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