A fix is available
APAR status
Closed as program error.
Error description
CICS is in a stall condition with most tasks hung in LMQUEUE suspends for the XM_LOCK or the SM_LOCK. The problem is similar to PK67128 except that the module here is DFHSMAR rather than DFHSMMF. Here the deadlock is between 2 tasks, one of which is terminating. During task termination, the task's storage is being freed when a storage violation is detected. DFHSMAR, in proc STORAGE_CHECK_FAILURE, then calls DFHXMIQ to increment the number of storage violations for the transaction. At the time of the call to DFHXMIQ, the task owns the SMLOCK. DFHXMIQ then tries to get the XMLOCK and suspends because the XMLOCK is owned by another task. The current owner of the XMLOCK is trying to acquire task storage and tries to get the SMLOCK. This causes a deadlock between the 2 tasks and other tasks begin to back up behind them. . It looks like DFHSMAR also needs to release the SMLOCK around the call DFHXMIQ. . Additional Symptom(s) Search Keyword(s): KIXREVSVR
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: All. * **************************************************************** * PROBLEM DESCRIPTION: Deadlock between two tasks caused by * * conflicting XMLOCK and SMLOCK requests. * **************************************************************** * RECOMMENDATION: * **************************************************************** There is a deadlock between a transaction that owns the SMLOCK and is waiting for the XMLOCK to be freed and another that owns the XMLOCK and is waiting for the SMLOCK to be freed. . Following a storage violation, procedure storage_check_failure in DFHSMAR is called as part of transaction termination. This holds the SMLOCK. DFHSMAR calls transaction manager function SET_TRANSACTION to update the number of storage violations which have occurred for the task. This requires the XMLOCK. At the same time a getmain is issued during the attach of another task. The getmain is for a KERNEL TASENTRY which is needed because the pool of static TASENTRY blocks has been exhausted due to a maxtask condition. This holds the XMLOCK and needs to obtain the SMLOCK. These two tasks deadlock each other and more tasks back up attempting to obtain the XMLOCK or SMLOCK. Further tasks back up on SMLOCK and XMLOCK until the region is cancelled. Additional Keywords: SM XM MSGDFHSM0102 DFHSM0102 SM0102
Problem conclusion
Procedure storage_check_failure in DFHSMAR has been changed to release and reacquire the SMLOCK around the transaction manager SET_TRANSACTION calls.
Temporary fix
********* * HIPER * ********* FIX AVAILABLE BY PTF ONLY
Comments
APAR Information
APAR number
PK97060
Reported component name
CICS TS Z/OS V4
Reported component ID
5655S9700
Reported release
600
Status
CLOSED PER
PE
NoPE
HIPER
YesHIPER
Special Attention
NoSpecatt
Submitted date
2009-09-24
Closed date
2009-10-02
Last modified date
2009-11-04
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UK50672
Modules/Macros
DESSMAR DFHSMAR
Fix information
Fixed component name
CICS TS Z/OS V4
Fixed component ID
5655S9700
Applicable component levels
R600 PSY UK50672
UP09/10/07 P F910
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:
04 November 2009