OA69826: ECSA OVERLAY AND S0C4 IN GZDHSIO WHEN SIO TRACE IS ON ZDMF/K

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• With DEBUG ON (or specifically, DWDBUG06_HSIO_FE_OK flag ON),
  the GZDHSIO tracing routine copies a channel program into the
  buffer without checking the buffer end. When tracing a looping
  CCW chain, this causes an ECSA overlay and an S0C4 abend in
  GZDHSIO itself.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: Users of IBM z/OS Data Set Mobility Facility *
  *                 who run with DEBUG ON.                       *
  ****************************************************************
  * PROBLEM DESCRIPTION: Abend S0C4 may occur in GZDHSIO when    *
  *                      DEBUG is ON.  In certain circumstances, *
  *                      ECSA storage may be overlaid, causing   *
  *                      further abends and failures in other    *
  *                      address spaces.                         *
  ****************************************************************
  * RECOMMENDATION: Apply the provided PTF.                      *
  ****************************************************************
  When DEBUG is ON, GZDHSIO traces channel programs by copying
  CCWs into an internal work area.  If a non-zHPF channel program
  contains a TIC that points back to an earlier CCW (a loop), the
  trace can run past the end of the work area and overlay the
  following ECSA storage, causing an abend S0C4 in GZDHSIO and
  failures in other address spaces.
  

Problem conclusion

• GZDHSIO is modified to check the end of the internal work area
  before copying, so the following ECSA storage is no longer
  overlaid, and to not follow a TIC that points back to an already
  traced CCW.  CCWs are no longer copied into the internal work
  area when TRACE is OFF.
  

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:

  UJ10236

Modules/Macros

• GZDHSIO
  

Fix information

• Fixed component name

  ZDMF

• Fixed component ID

  ZDMF00001

Applicable component levels

• R341 PSY UJ10236

     UP26/08/14 I 1000

Fix is available

• Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.