A fix is available
APAR status
Closed as program error.
Error description
You receive DFHLDLD1 abend (code 0C4/AKEX) has occurred at offset X'0980' in module DFHLDLD1. This was most likely caused by doing a mass Discard of all the DB2ENTRYs. You suffer an overlay of the APE (Active Program Element) block in CICS. What is bad about it is +X'18' ( APE_NEXT) is a value of x'00000000'. This results in the ABEBD0C4. Additional symptoms: A word of storage is overlayed with binary zeroes . This overlayed word is at one of several offsets into a page of ECDSA storage. The potential offsets are 0E8 1B0 278 340 408 4D0 598 660 728 7F0 8B8 980 A48 B10 BD8 CA0 D68 E30 EF8 or FC0 . . This problem happens when a DB2ENTRY resource is discarded. When that happens, the DFHD2ENT control block representing the DB2ENTRY is freemained . At that time, the chain of CSUBs anchored in that DFHD2ENT at RCT_FREE_CONN_CHAIN (DFHD2ENT+X'B8' should be made to no longer point back to the just freed DFHD2ENT . But that sometimes does not happen. Later, this page of storage that used to contain DFHD2ENTs can be used for a different control block. And then later, a free CSUB (which points into the old page of DFHD2ENTs) can be picked up off the GLB_FREE_CONN_CHAIN at which point the unchain code will clear the word of storage at what used to be DFHD2ENT+X'B8'. This can cause any type of ECDSA storage to get overlayed sometimes days after the discard of the DB2ENTRY. . The offset above are based on the offsets of the beginning of the DFHD2ENTs in a page of DFHD2ENTs +X'B8' which is RCT_FREE_CONN_CHAIN . zeros X'00000000'
Local fix
KIXREVRJL
Problem summary
**************************************************************** * USERS AFFECTED: All. * **************************************************************** * PROBLEM DESCRIPTION: Abend 0C4/AKEX in DFHLDLD1. * **************************************************************** * RECOMMENDATION: * **************************************************************** This problem presented as an abend 0C4 in DFHLDLD1. Prior to the abend, a DISCARD of DB2ENTRYs had occurred which in turn caused the DB2ENTRY control blocks to be freed. As part of freeing the DB2ENTRY control blocks, DFHD2TM should have freed 2 CSUB chains anchored from the DB2ENTRY, the protected CSUB chain and the global free CSUB chain. However, DFHD2TM cleared the anchor pointer to the global free CSUB chain as part of freeing the CSUBs on the protected chain all as part of freeing the DB2ENTRY. As a consequence, CSUBs on the global free chain were available for reuse but containing invalid pointer references to storage that was once a DB2ENTRY but was now ( for example ) an LD_APE, thus causing the 0C4 when these invalid pointer references are used. Keywords: abend0C4 abendS0C4 S0C4 LD0001 msgDFHLD0001 DFHLD0001
Problem conclusion
DFHD2TM has been modified and will not orphan the CSUBs on the global free chain.
Temporary fix
FIX AVAILABLE BY PTF ONLY
Comments
APAR Information
APAR number
PM16615
Reported component name
CICS TS Z/OS V4
Reported component ID
5655S9700
Reported release
600
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2010-06-16
Closed date
2010-06-24
Last modified date
2010-07-02
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UK58211
Modules/Macros
DESD2TM DFHD2TM
Fix information
Fixed component name
CICS TS Z/OS V4
Fixed component ID
5655S9700
Applicable component levels
R600 PSY UK58211
UP10/07/01 P F006
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.
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Document Information
Modified date:
02 July 2010