A fix is available
APAR status
Closed as program error.
Error description
CICS region that does a lot of BTS work puts out the following error messages: . DFHBA0001 An abend (code 0C4/AKEA) has occurred at offset X'1226' in module DFHBAXM. DFHDS0002 A severe error (code X'0071') has occurred in module DFHDSSR. DFHXM0306 A severe error (code X'1334') has occurred while initializing task number xxxxx with transaction identifier TTTT. The task is suspended indefinitely. . The dump shows that CICS was at MXT with most tasks backed up in XMPARENT suspends, waiting for a child task to complete. However, some of the child tasks are held for MXT reasons and don't get a chance to run, so the region became deadlocked. Eventually, tasks started getting purged (AEXY abends). The 0C4 and DFHDS0002 0071 errors seem to have occurred when the parent task is purged out from under the child task. The XMPARENT suspends should not be purgeable with CICS. . The parent tasks created a control block in their own stack storage to represent the client_data_block. This gets passed to the child task as the REQUEST_BLOCK. When the child of a purged parent gets to run, this REQUEST_BLOCK is no longer valid. This causes the DFHBA0001 0C4 program checks. . The CICS trace entry at time of 0C4 looks like this: . BA 0172 BAXM *EXC* - Recovery_entered FUNCTION(BIND_ACTIVITY_REQUEST) REQUEST_BLOCK(4D257508 , 00000113) . When the BAXM BIND_XM_CLIENT request failed for the child task, that task goes on to issue message DFHXM0306, to inform the user that the task will be suspended indefinitely. But first, there is an attempt to notify the primary client that this task is going to suspend indefinitely. This involves issuing a RESUME for the BTS parent task. But the suspend token used for the RESUME is not valid any longer since the parent task is gone, and the DFHDS0002 0071 error is then issued. The CICS exception trace entry looks like this: . DS 0071 DSSR *EXC* - RESUME_INVALID_SUSP_TOK - FUNCTION(RESUME) SUSPEND_TOKEN(0406035D)
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: All CICS users. * **************************************************************** * PROBLEM DESCRIPTION: S0C4 in DFHBAXM BIND_ACTIVITY_REQUEST * * processing, followed by DS0071 * * RESUME_INVALID_SUSP_TOK after task * * purged from XMPARENT suspend. * **************************************************************** * RECOMMENDATION: * **************************************************************** A task is waiting in an XMPARENT suspend following an XMRU RUN_TRANSACTION call, issued as part of an EXEC CICS RUN PROCESS command. The child task is created, but is queued on MXT/TCLASS. The parent is purged from the XMPARENT suspend before the child task is able to run. When the parent is purged, the shared memory area (xmcn_context) is FREEMAINed. When the child task is able to run, it attempts to access the xmcn_context. This area has since been reused, so the data there is no longer reliable. In the reported instance the effect was an 0C4 program check in DFHBAXM BIND_ACTIVITY_REQUEST, called from DFHXMXM BIND_XM_CLIENT. This occurred when DFHBAXM attempted to read the activity request (activity_req) addressed from the primary client block (primary_client_block). This caused the transaction bind to fail, and DFHXMTA began to abend the transaction. This led to an attempt to notify the primary client (in this case XM domain). DFHXMXM was called for NOTIFY_TRANSACTION_HANG, leading to a DSSR RESUME call for the parent transaction. The storage holding the parent_suspend_token was no longer reliable, and the parent had already been purged, so this RESUME failed with DS 0071 RESUME_INVALID_SUSP_TOK. Additional Keywords: msgDFHDS0071 DFHDS0071 DS0002 abendS0C4 msgDFHXM0306 DFHXM0306 XM0306
Problem conclusion
DFHXMRM has been changed to ensure that the xmcn_context is not FREEMAINed if the parent is purged before the child task is allowed to run. DFHXMXM has been changed so that DFHBAXM BIND_ACTIVITY_REQUEST is not called during BIND_XM_CLIENT if the parent task has been purged. Instead, the child task will abend with a new abend code "ARUD". . The CICS Transaction Server for z/OS Version 5 Release 1 CICS Messages and Codes Vol 1 manual (GC34-2861-00) will be updated in chapter 2 with a new abend code; ARUD. . ARUD Explanation A RUN SYNCHRONOUS command caused an attempt to attach a child transaction. The parent transaction which issued the RUN SYNCHRONOUS command was then purged before the child task could be run. . System action CICS terminates the invoked transaction abnormally with a transaction dump. . User response None. . Module DFHXMXM
Temporary fix
FIX AVAILABLE BY PTF ONLY
Comments
APAR Information
APAR number
PI12967
Reported component name
CICS TS Z/OS V5
Reported component ID
5655Y0400
Reported release
800
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2014-03-04
Closed date
2014-03-28
Last modified date
2015-03-05
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UI16722
Modules/Macros
DFHXMDM DFHXMRM1 DFHXMRM DFHXMRU DFHXMTA DFHXMXM
GC34286100 |
Fix information
Fixed component name
CICS TS Z/OS V5
Fixed component ID
5655Y0400
Applicable component levels
R800 PSY UI16722
UP14/04/11 P F404
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:
05 March 2015