A fix is available
APAR status
Closed as program error.
Error description
Task user storage gets corrupted with VSAM file record data. A FCP Free BUFFER chain header has been corrupted with an address of task storage. . The sequence of API commands issued by the application leading to the problem is as follows: EXEC CICS STARTBROWSE FILE EXEC CICS READ_NEXT FILE SET EXEC CICS READ FILE SET UPDATE EXEC CICS REWRITE FILE . Then the application issues an EXEC CICS SYNCPOINT ROLLBACK. . The READ_NEXT command getmains its SET storage and places the address in an associated FRTE. The READ UPDATE command getmains its SET storage, and places the address in an associated FRTE. On exit from the REWRITE command, the FRTE for the READ UPDATE gets released and the SET storage address now appears in the FLAB (flab_setu_control) for the file. At this point, there is a SET address for the Browser's READ_NEXT in a FRTE and the SET address for the READ UPDATE in the flab_setu_control. Code in DFHFCFR checks if the buffer address in the FRTE is different to the SET address in the FLAB. If so, then the FRTE SET address is placed on the Free Buffer chain. This is incorrect, the address in the FRTE is task storage and not from the FCP_256 subpool. The free buffer chain now contains a storage address that does not belong to file control. Consequently, when file control needs a SET storage address, it takes the next buffer from the free buffer chain causing symptoms such as storage violations, abends in file control and abends in VSAM. Additional symptoms: Storage Violations SM0102 IGW400I ABEND request GET with options 22870000
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: All CICS users. * **************************************************************** * PROBLEM DESCRIPTION: An FCP Free BUFFER chain header has * * been corrupted with an address of task * * storage when preparing to back out a * * FRTE for a browse operation. * **************************************************************** An EXEC CICS SYNCPOINT ROLLBACK command issued after the following sequence of File Control commands caused CICS to place the address of task storage (FCSS SET storage used by file control) onto the head of the buffer free chain. EXEC CICS STARTBR FILE EXEC CICS READ_NEXT FILE SET EXEC CICS READ FILE UPDATE SET EXEC CICS REWRITE FILE Later, when File Control needs a SET storage address and takes the address from the head of the buffer free chain, it may cause symptoms such as storage violations, abends in file control and abends in VSAM.
Problem conclusion
DFHFCFR has been changed to not place the frt_data_buffer address onto the free buffer chain when preparing to back out a FRTE for a browse operation.
Temporary fix
Comments
APAR Information
APAR number
PH54109
Reported component name
CICS TS Z/OS V5
Reported component ID
5655Y0400
Reported release
100
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2023-04-24
Closed date
2023-06-30
Last modified date
2023-07-04
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UI92552 UI92553
Modules/Macros
DFHFCFR
Fix information
Fixed component name
CICS TS Z/OS V5
Fixed component ID
5655Y0400
Applicable component levels
Fix is available
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Document Information
Modified date:
04 July 2023