PH30341: IBM MQ SYM=AB/S00C4 ABN=0C4-00000010,U=ABC ,C=MQ900 CSQIDUSE

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• During the process of deleting a PSID, IBM MQ generates a dump
  with the above abending symptom string. The control block
  linkage from PANC -> PSET -> BHDR performs an unexpected
  reference. Hursley finds the following timing window that (a)
  When DISPLAY USAGE is issued, processing suspends to wait for
  page set I/O (b) DELETE PSID command runs and completes (c) The
  DELETE process  causes the PSET pointer to be cleared followed
  by I/O processing also finishing (d) DISPLAY USAGE processing
  resumes, attempting to reference the PSET pointer which was
  just cleared, resulting in the abend.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All Users of IBM MQ for z/OS Version 9       *
  *                 Release 1 Modification 0 and Release 2       *
  *                 Modification 0.                              *
  ****************************************************************
  * PROBLEM DESCRIPTION: When issuing a DISPLAY PSID command,    *
  *                      there is a timing window during which   *
  *                      an automated program can issue and      *
  *                      finish a DELETE PSID command for        *
  *                      that same pageset, and cause an 0C4     *
  *                      abend when CSQIDUSE attempts to use the *
  *                      pageset's pointer value.                *
  ****************************************************************
  In CSQIDUSE, there is an occasion where the pageset's
  pointer is dereferenced without being checked for validity.
  
  There is a timing window - before this pointer access
  during which a DELETE PSID command could remove the pageset and
  invalidate the pointer.
  

Problem conclusion

• CSQIDUSE has been modified to prevent the 0C4 ABEND from
  occurring.
  

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:

  UI72438 UI72439

Modules/Macros

• CSQIDUSE CSQISTA1
  

Fix information

• Fixed component name

  IBM MQ Z/OS V9

• Fixed component ID

  5655MQ900

Applicable component levels

• R100 PSY UI72438

     UP20/12/07 P F012

• R200 PSY UI72439

     UP20/12/07 P F012

Fix is available

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