A fix is available
APAR status
Closed as program error.
Error description
Your CICS region experiences an AKEC abend in tran CRST for exceeding the ICVR value. You may also (but no necessarily) see DFHRS0007E. . . Additional Symptom(s) Search Keyword(s): KIXREVxxx
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: CICSPlex SM users using sysplex optimised * * workload management. * **************************************************************** * PROBLEM DESCRIPTION: The CICS RS domain long running task * * CRST gets caught running a tight loop * * and is abended by CICS runaway. * * CICS issues msgDFHRS0004 * * +DFHRS0004 applid A possible loop has * * been detected at offset X'FFFF' * * in module DFHRSTP. * **************************************************************** When a user task executing in CICS issues a transaction dump, CICS RS domain (DFHRSDU) is notified (RSDU START_TDUMP). This updates the region status record in the DFHRSTAT coupling facility data table, to show that a dump is in progress. When the transaction dump completes RS domain will be notified again (RSDU STOP_TDUMP). DFHRSTAT is not updated again immediately. Instead the RS domain long running task CRST is notified. The CRST task will process this notification after a short delay, and will sleep until then. . After one second has passed, the CRST task will wake up and be redispatched on the QR TCB. At this time it will attempt to update DFHRSTAT (dump no longer in progress). In the reported problem, another task in the system happened to be in termination. That task ending causes the task load in the region to drop down one tier boundary (see UPDATERS), which causes the task to update DFHRSTAT. This task happened to be executing under an open TCB, and so attempted to switch to the QR TCB to complete the CFDT request. . This created a deadlock between the two tasks. The user task could not get dispatched under QR to complete the CFDT request because CRST was executing on the QR TCB. A logic error in program DFHRSTP meant that it entered a loop which it then could not exit until the currently in flight CFDT update had completed. The deadlock condition is eventually terminated when the CICS Runaway interval (as controlled by the ICVR system initialization parameter) expires. At that time the CRST task is purged. CICS will issue message DFHRS0004 and then automatically restart the CRST task. . +DFHRS0004 applid A possible loop has been detected at offset X'FFFF' in module DFHRSTP. . Additional Keywords: RS0004 rstp_proc_loop CF_update_in_progress AKEC abendAKEC
Problem conclusion
DFHRSTP has been updated to avoid the loop condition when another task is currently updating the CFDT.
Temporary fix
Comments
APAR Information
APAR number
PH11867
Reported component name
CICS TS Z/OS V5
Reported component ID
5655Y0400
Reported release
10M
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2019-05-07
Closed date
2019-09-05
Last modified date
2019-10-01
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UI65147 UI65148
Modules/Macros
DFHRSTP
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:
01 October 2019