A fix is available
APAR status
Closed as program error.
Error description
During logon IKTXINIT sends a query to the device that is logging on. The loop occurs when the query reply returns with too much data. IKTXINIT has a fixed size for the QUERY reply data. When the length of data to be received exceeds that fixed size, then IKTXINIT loops repeating its RECEIVE SPECIFIC at offset x'1286'. In this case IKTXINIT was V1R9 base. While the LU is sending in the too large query reply, IKTXINIT should not loop. The APAR is taken to correct the loop. IKTXINIT initiates the loop by issuing the RECEIVE. Other modules are in the loop, processing the RECEIVE. System trace shows the following repeating sequence. ---------------------------------------------------------------- DSP 070C0000 80C96400 00000000 00000001 00006C68 00000000 >>> Address 80C96400 is in ISTAICI2+1A18 (label cckriuwt). SVC 1 070C0000 80C96400 00000000 00000001 00006C68 Wait SVCR 1 070C0000 80C96400 809FFF98 00000001 00006C68 SRB 070C0000 A8E75150 FFFF00BD 22D7B44C 22D7B390 00 009FFB00 00 >>> Address A8E75150 is the entry of ISTAPCAD (VTAM dispatcher). SSRV 129 A8E74558 00006C68 00000000 00000000 Post 00000000 >>> Address A8E74558 is in ISTAICPT+11B8 (after 05EF to POST). ---------------------------------------------------------------- The looping address space has name "unknown". The VTAM internal trace will show the repeating sequence of entries: REQS, REQS, AI1, AI2, QUE TSIR, RELS, REQS, DSP TSIR, UP, RELS, VPST ISTAICPT, EXIT TSIR
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: All TSO users. * **************************************************************** * PROBLEM DESCRIPTION: IKTXINIT loop issuing RECEIVE macro * * to receive the query data during the * * logon to TSO. * **************************************************************** * RECOMMENDATION: * **************************************************************** This problem is described as follows: 1. User tried to logon to TSO. 2. IKTXINIT received control to process the logon. 3. It issued the SEND macro to get the query data from the terminal to determine the device characteristics. 4. It issued the RECEIVE macro to receive the query data from the terminal. 5. Terminal responded with the invalid very large query data information and its data length was higher than 4096 bytes. 6. IKTXINIT received 4096 bytes of data from the terminal. 7. It issued RECEIVE macro again to receive the remaining data with the RPL length of zero bytes and invalid buffer address. 8. VTAM returned to IKTXINIT with the zero bytes of data. 9. IKTXINIT repeated the steps 7 and 8 forever. This caused the loop in IKTXINIT and VTAM.
Problem conclusion
IKTXINIT has been changed to receive the query data up to 4096 bytes. If the query reply is longer than 4096 bytes, it will reject the logon with the new message IKT125I and issue an ABEND0AB RC 204 to end the user address space. IKTMSGS, IKTTVMSG and ISTVTMEU have been changed to add a new message IKT125I. ------------------------------------------------------------- The request for the publication change has been submitted as follows: Title: z/OS Communications Server: IP and SNA Codes Release: z/OS V1R7 and higher. Document Number: SC31-8791-05 In the Chapter 7 - VTAM abend codes, under the topic of Abend code 0AB: Add the register 15 return code 204 after the return code 203 as follows: 0204 During a logon for the TSO application, TSO/VTAM issued a QUERY 3270 data stream to determine the characteristics of the terminal. The response to the query was more than 4096 bytes. ------------------------------------------------------------- The request for the publication change has been submitted as follows for another book: Title: z/OS Communications Server SNA Messages Release: z/OS V1R7 and higher. Document Number: SC31-8790-05 In the Chapter 3 - IKT messages for TSO/VTAM network operators Add a new message IKT125I after IKT124I as follows: IKT125I TSO LOGON REJECTED: QUERY REPLY TOO LARGE - TERMINAL ID termid Explanation: During a logon for the TSO application, TSO/VTAM issued a QUERY 3270 data stream to determine characteristics of the terminal. The response to the query was more than allowed 4096 bytes. termid is the LU name of the terminal. System Action: The user address space ends and ABEND0AB RC 204 is issued. System processing continues. Operator Response: Save the dump and system log for problem determination. Contact the System Programmer. System Programmer Response: If you can not determine the cause of the problem from the output provided or need additional assistance, contact the IBM software support center. Routing code: 1,8
Temporary fix
********* * HIPER * *********
Comments
APAR Information
APAR number
OA24775
Reported component name
VTAM V4 MVS/ESA
Reported component ID
569511701
Reported release
190
Status
CLOSED PER
PE
NoPE
HIPER
YesHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2008-04-16
Closed date
2008-05-09
Last modified date
2008-06-03
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UA41007 UA41008 UA41009 UA41010
Modules/Macros
IKTMSGS IKTTVMSG IKTXINIT ISTVTMEU
SC31879007 | SC31879107 | SC31879006 | SC31879106 | SC31879005 |
SC31879105 | SC31879008 | SC31879108 |
Fix information
Fixed component name
VTAM V4 MVS/ESA
Fixed component ID
569511701
Applicable component levels
R1A0 PSY UA41007
UP08/05/31 P F805
R170 PSY UA41008
UP08/05/29 P F805
R180 PSY UA41009
UP08/05/29 P F805
R190 PSY UA41010
UP08/05/29 P F805
Fix is available
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Document Information
Modified date:
03 June 2008