PJ40711: DASD SSID CHANGE CAUSED A DEVICE TO BE CROSS-LINKED ON TWO SSST CHAINS RESULTING IN A LOOPING ECB AND SYSTEM HANG.

APAR status

• Closed as program error.

Error description

• See Problem Summary.
  

Local fix

• na
  

Problem summary

• PAR NUMBER:  PJ40711
  PRODUCT:  z/TPF
  FUNCTIONAL AREA:  RECORD CACHE SUBSYSTEM
  SHIPPED IN PUT:  10
  
  ABSTRACT:
  A DASD subsystem ID (SSID) changed during a VM Hyperswap
  causing a device to be cross-linked on two subsystem status
  table (SSST) chains. This resulted in a CYEA CTL-10 and system
  hang.
  
  PACKAGE CONTENTS:
  Source Segments:
  (C) base/rt/css2.asm
  (C) base/macro/cz1se.mac
  
  Object Only Binaries:
  None.
  
  Configuration Independent Binaries:
  (C) base/load/CSS2.so
  (C) base/obj/css2.o
  
  Support Files:
  base/lst/CSS2.map
  base/lst/css2.lst
  
  OTHER BINARIES TO BUILD: YES
  (C) os390/bin/amx1.pds
  (C) os390/bin/ppcp.pds
  (C) os390/bin/stc.pds
  (C) os390/obj/amx1.o
  (C) os390/obj/ccmcdc.o
  (C) os390/obj/dgr0.o
  (C) os390/obj/sdmu.o
  (C) os390/obj/stcc.o
  (C) os390/obj/stci.o
  (C) os390/obj/stcl.o
  (C) os390/obj/stpp.o
  
  COMMENTS:
  When a VM Hyperswap occurred and switched DASD controllers, a
  state-change-pending interrupt was presented triggering TPF to
  query status. The query returned a different SSID than was
  detected at IPL time when the reporting device was mounted.
  Since the new SSID was not found in the SSST, TPF created a new
  entry and chained the reporting device to it, assuming it was a
  new device entering the configuration for the first time. Since
  the device was already mounted, this action caused it to be
  cross-linked on two SSST chains. A CTL-10 in CYEA occurred
  followed by a system hang, since it was unable to react to
  subsequent state change interrupts. A manual IPL was required.
  

Problem conclusion

• SOLUTION:
  CSS2.ASM has been modified to check if a device is already
  mounted on another SSST chain, when the SSID reported following
  a state-change is not found in the SSST. If it is already
  mounted, the old SSID and existing SSST slot will be reused to
  avoid cross-linking problems. CSS2.ASM will issue a SNAPC dump
  to capture diagnostic data. An IPL is recommended, at the
  earliest convenience, to rebuild the SSST with the current
  SSIDs.
  
  COREQS: NO
  None.
  
  MIGRATION CONSIDERATIONS: YES
  Functional, automation, and operation changes:
  A new snapc dump, 001245, has been created to report an SSID
  mismatch.
  
  
  
  BUILD COMMANDS AND INSTRUCTIONS: YES
  #maketpf commands for linux
  maketpf -f CSS2 css2.o
  maketpf CSS2 link
  #maketpf commands for z/OS
  maketpf -f amx1 amx1.o
  maketpf -f ppcp ccmcdc.o stpp.o
  maketpf -f stc dgr0.o sdmu.o stcc.o stci.o stcl.o
  maketpf amx1 link
  maketpf ppcp link
  maketpf stc link
  
  UPDATED INFORMATION UNITS: YES
  z/TPF Messages (System Error, Offline, and Program Status Word)
  
  See your IBM representative if you need additional information.
  
  DOWNLOAD INSTRUCTIONS:
  http://www.ibm.com/software/htp/tpf/maint/maintztpf.html
  
  APAR URL:
  http://www.ibm.com/software/htp/tpf/ztpfmaint/put10/PJ40711.htm
  

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:

Publications Referenced

SK2T8062

Fix information

• Fixed component name

  Z/TPF

• Fixed component ID

  5748T1501

Applicable component levels

• R110 PSY UP

     110