A fix is available
APAR status
Closed as program error.
Error description
After applying maintenance the customer is encountering a loop in module DFHLMLM (base level). This is occurring because the code in DFHLMLM UNLOCK_SHARED is in a loop trying to unlock XMATTLCK because its LM_CS_COUNT has gone negatve. . Additional Keywords: DFHLMLM DFHLM0004 LOOP XMATTLCK LM_CS_COUNT KIXREVACC
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: All CICS Users with PI85926 applied. * **************************************************************** * PROBLEM DESCRIPTION: CWXN can go into a tight loop which * * results in message DFHLM0004 being * * issued. * **************************************************************** CICS has been up and running for a while and then issues message DFHLM0004 A possible loop has been detected at offset X'FFFF' in module DFHLMLM. The shared lock, XMATTLCK will be acquired. A code path in DFHXMAT will issue a change mode to the QR TCB, but if this is not required, because the task is already on the QR TCB, the function call type will be lost. This function call type is required to free the shared XMATTLCK. When enough transactions have executed which have acquired the lock but then not freed it, its lock count will go negative. When the next CWXN then tries to unlock the XMATTLCK code in DFHLMLM will loop because of the negative lock count.
Problem conclusion
UI50631 UI51182 UI51932 UI53069 DFHXMTA has been changed to ensure the function call type is not lost when the change mode is not required..
Temporary fix
Comments
APAR Information
APAR number
PI96253
Reported component name
CICS TS Z/OS V5
Reported component ID
5655Y0400
Reported release
000
Status
CLOSED PER
PE
YesPE
HIPER
YesHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2018-04-05
Closed date
2018-04-19
Last modified date
2018-05-08
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UI55321 UI55320
Modules/Macros
DFH$CAT1 DFHD2DUF DFHD2EX1 DFHD2IN1 DFHD2IN2 DFHD2RP DFHD2STP DFHD2STR DFHD2TM DFHD2TRI DFHDSTCB DFHECIS DFHECIST DFHECRL DFHECSC DFHEIFC DFHEIG DFHEIP DFHEPC DFHERM DFHFCDL DFHFCDR DFHFCFS DFHFCIN1 DFHFCMT DFHFCRC2 DFHFCRP DFHFCRR DFHFCSDS DFHFORMS DFHME64 DFHMEDM DFHMEDUF DFHMEME DFHMEMPC DFHMEMPE DFHMEMPK DFHMPAC DFHMPACT DFHMPDD DFHMPDDT DFHMPDE DFHMPDM DFHMPDUF DFHMPFED DFHMPIB DFHMPIBT DFHMPMO DFHMPPP DFHMPRL DFHMPSC DFHMPSCT DFHMPST DFHMPTRI DFHS2GF DFHSIB1 DFHSMGF DFHSMMF DFHSMMG DFHSTNDD DFHXMAB DFHXMAT DFHXMCL DFHXMCLT DFHXMCLX DFHXMCLY DFHXMDM DFHXMDU2 DFHXMDUF DFHXMER DFHXMERT DFHXMQC DFHXMQCT DFHXMRSD DFHXMTA DFHXMTRI DFHXMXE DFHXSDM DFHXSRC
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:
08 May 2018