A fix is available
APAR status
Closed as program error.
Error description
ABEND04E RC00E20028 occurred after a 1 byte storage overlay of an SKB control block. The two bytes should be X'00AD'. However, they were X'01AD' for the incident reported. After the thread abended, its invalid SKB was neither validated nor cleaned up, and was put back on the free SKB chain for subsequent agents to pick up, which caused the abend to occur multiple times. Keywords: SMCOVERLAY DB2STGLK/K
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: All DB2 V8 ( HDB8810 ) and V9 ( HDB9910 ) * * users. * **************************************************************** * PROBLEM DESCRIPTION: ABEND04E RC00E20028 may occur * * repeatedly on different threads for * * the same SKB segment storage. If the * * abend occurs for a DB2 must-complete * * thread, a subsystem termination occurs. * **************************************************************** * RECOMMENDATION: * **************************************************************** Abends which occur due to STACK storage ( SKB ) validation overlays, result in ABEND04E RC00E20028. The thread cleanup code then puts this damaged SKB back onto the stack cache without repairing the damage. When this stack storage is allocated by another thread, the same abend will occur and if the overlaid SKB is being used by a DB2 must-complete process, DB2 terminates.
Problem conclusion
The modules which manage SKB stack storage have been changed to perform more validation as they are manipulating thread stack. If an overlay is detected, the thread will ABEND04E RC00E20028 and during the abort cleanup process the overlaid SKB segment will be freemained rather than cached. This will prevent multiple dumps occurring due to the same overlay and capture documentation closer to the actual overlay.
Temporary fix
Comments
APAR Information
APAR number
PM02532
Reported component name
DB2 OS/390 & Z/
Reported component ID
5740XYR00
Reported release
810
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2009-12-01
Closed date
2010-02-04
Last modified date
2011-02-15
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UK54133 UK54134
Modules/Macros
DSNSPURS DSNSTACK DSNSVSTK
Fix information
Fixed component name
DB2 OS/390 & Z/
Fixed component ID
5740XYR00
Applicable component levels
Fix is available
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Document Information
Modified date:
15 February 2011