Loop in VSAM record management code

When processing a VSAM data set, a loop may occur in VSAM record management code.

Symptoms

A job that is processing VSAM data sets stops doing I/O to the VSAM data sets and is continuing to use CPU
RMF or other Monitors may indicate that a job is using CPU in a VSAM module named IDA019xx
Some applications may indicate that a loop is occurring. For example, CICS will issue message DFHFC0004 indicating a loop at offset X’FFFF’ in module DFHFCVR.

Obtain system dump of address space with the following SDATA: SDATA=(ALLNUC,CSA,GRSQ,LPA,LSQA,PSA,RGN,SQA,SUM,SWA,TRT)
If the monitor includes detail on the data set that the last request was for, obtain an IDCAMS LISTCAT ALL of the data set and any associated data sets such as AIX’s
```
//STEP1    EXEC  PGM=IDCAMS,REGION=0M	  
//SYSPRINT DD    SYSOUT=A	 
//SYSIN    DD *   
  LISTCAT ENT(VSAM.DATA.SET) ALL
```
Submit the dump, LISTCAT output (if available), joblog from the job that is hung, and syslog to the Support Center.

Cancel or shutdown the hung job and attempt to restart.