A fix is available
APAR status
Closed as program error.
Error description
You are running CICS TS 5.6 and the region has been up for 6 days. This region processes incoming socket connections and also DPLs from other regions. On the 6th day, mirror tasks start abending with code AITC that indicates an unexpected response from the Recovery Manager domain. Looking at the Link Summary in the RM domain of A dump taken at the time of the AITC, abend showed over 60,000 SOCK client entries, Link id- SOCKLINK. Here is a sample of this: Link Owning Client Client Remote Link Token UOW Addr Name Token Access Id Id 0173000E address SOCK 01040025 DEFAULT SOCKLINK 01720011 address SOCK 01030032 DEFAULT SOCKLINK 01760001 address SOCK 01040027 DEFAULT SOCKLINK 01750004 address SOCK 01040029 DEFAULT SOCKLINK Here are the CICS trace entries for the mirror task leading up to the AITC abend: RM 0301 RMLN ENTRY SET_LINK 00000000,UNNECESSARY RM 0302 RMLN EXIT SET_LINK/EXCEPTION LINK_UNKNOWN AP 2000 PCPG ENTRY ABEND AP 0741 ABAB ENTRY CREATE_ABEND_RECORD DFHMIRS,AITC Looking back at the messages in MSGUSR for the previous 6 days, we found thousands of messages related to sockets. Here is an example: DFHSO1002 CICS is unable to determine the secure state of a new connection received on ATTLSAWARE DFHSO1002 CICS is unable to determine the secure state of a new connection received on ATTLSAWARE TCPIPSERVICE service from client IP address .. UNIX System Services values returned are bpx_return_value( -1 ), bpx_return_code( 1,124 ), and bpx_reason_code( X'77B77221' ). Return code 1124 means ENOTCONN- the client has closed the connection. In the CICS Trace, here are examples of the exception trace entries for our main listener task CSOL: 00004 SL SO 0E1C SOUS *EXC* GETSOCKNAME_FAILURE RETURN_VALUE(-1) RETURN_CODE(1124) 00004 SL SO 0E1C SOUS *EXC* GETSOCKNAME_FAILURE RETURN_VALUE(-1) RETURN_CODE(1124) 00004 SL SO 0CAB SOLS *EXC* SIOCTTLSCTL_ERROR RETURN_VALUE(-1) RETURN_CODE(1124) After the GETSOCKNAME ends with the client has disconnected, CICS is not cleaning up the RM link for the socket and not freemaining the buffer obtained from subpool ASYNC4K. Additional symptoms: KIXREVDAM REASON_CODE 749B0000 AT-TLS aware LINK TOKEN ADD_LINK client name SOCK disconnect socket
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: All CICS users * **************************************************************** * PROBLEM DESCRIPTION: DFHAC2236 ABEND AITC DFHMIRS can occur * * after receiving many DFHSO1002 due to * * build up of RM_link tokens and async4k * * buffers. * **************************************************************** When a new connection arrives in CICS on an ATTLSAWARE TCPIPSERVICE, CICS obtains information related to the connection to store in its control blocks. If CICS finds that the connection has been closed, DFHSOLS cleans up the control blocks associated with the socket, but fails to delete the RM_LINK and doesn't delete the async4k buffer. This results in a build up of RM Link tokens and aysnc4k buffers and many DFHSO1002 messages in the error log leading to AITC abend that indicates an unexpected response from the Recovery Manager domain.
Problem conclusion
UI90657 UI93697 UI83808 UI93696 UI90656 UI83807 DFHSOLS has been changed to relinquish the RM_LINK and freemain the async4k buffer when cleaning up the control blocks.
Temporary fix
Comments
APAR Information
APAR number
PH59944
Reported component name
CICS TS Z/OS V5
Reported component ID
5655Y0400
Reported release
300
Status
CLOSED PER
PE
YesPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2024-02-21
Closed date
2024-04-09
Last modified date
2024-05-01
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
PH60291 UI96411 UI96412
Modules/Macros
DFHLEPTS DFHMESOC DFHMESOE DFHMESOK DFHSOAD DFHSOCK DFHSODM DFHSODS DFHSODUF DFHSOGH@ DFHSOHN DFHSOIS DFHSOL DFHSOLI DFHSOLS DFHSOLX DFHSOLX6 DFHSOM01 DFHSOM02 DFHSOM03 DFHSONT DFHSOPL DFHSORD DFHSORL DFHSORM DFHSOS00 DFHSOS01 DFHSOS02 DFHSOS03 DFHSOS04 DFHSOS05 DFHSOS06 DFHSOS07 DFHSOS08 DFHSOS09 DFHSOS10 DFHSOS11 DFHSOS12 DFHSOS13 DFHSOS14 DFHSOS15 DFHSOS16 DFHSOS17 DFHSOS18 DFHSOS19 DFHSOS20 DFHSOS21 DFHSOS22 DFHSOS23 DFHSOSE DFHSOSES DFHSOSK DFHSOSM DFHSOST DFHSOTB DFHSOTI DFHSOTRI DFHSOUE DFHSOXM
Fix information
Fixed component name
CICS TS Z/OS V5
Fixed component ID
5655Y0400
Applicable component levels
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:
02 May 2024