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PI40953: Service for Debug Tool 13.1.

A fix is available

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APAR status

  • Closed as program error.

Error description

  • AbendS878 occurs with Debug Tool in CICS JVM environment due to
    SCB leak.
    Additional symptoms: ABEND878 and ESTAEX EQANCEST
    (PI40953 at 13.1)
    The current execution line does not move when stepping through
    a large application where the DSA chain exceeds 100 save areas.
    Instead, line 1 is constantly highlighted and the QUERY
    LOCATION command indicated the program is at line 0.
    (PI41131 at 12.1)
    AbendS0C1 from entry @@DPIFN1 when using z/OS 1.13 LE and
    debugging a C or C++ program.
    .
    Additional Symptoms in CICS Address Spaces
    .
    You may suffer S878, S80A or code 878/AKEX abends. An SVC dump
    will show an unusually high LSQA usage below the line ( subpool
    255 key 0 storage.)
    .
    Using VERBX VSMDATA 'NOG SUMM' to examine the storage pattern,
    you may see something similar to this in the AQAT:
    .
    AQAT: Addr 00751000 Size   113000
              DFE: Addr 00751000 Size      600
              DFE: Addr 00752000 Size      100
              DFE: Addr 00753000 Size      100
              DFE: Addr 00754000 Size      100
              DFE: Addr 00755000 Size      100
              DFE: Addr 00756000 Size      100
              DFE: Addr 00757000 Size      100
              DFE: Addr 00758000 Size      100
              DFE: Addr 00759000 Size      100
              DFE: Addr 0075A000 Size      100
              DFE: Addr 0075B000 Size      100
              DFE: Addr 0075C000 Size      100
              DFE: Addr 0075D000 Size      100
              DFE: Addr 0075E000 Size      100
              DFE: Addr 0075F000 Size      100
              DFE: Addr 00760000 Size      100
              DFE: Addr 00761000 Size      100
              DFE: Addr 00762000 Size      100
              DFE: Addr 00763000 Size      100
              DFE: Addr 00764000 Size      100
              DFE: Addr 00765000 Size      100
              DFE: Addr 00766000 Size      100
              DFE: Addr 00767000 Size      100
              DFE: Addr 00768000 Size      100
              DFE: Addr 00769000 Size      100
              DFE: Addr 0076A000 Size      100
              DFE: Addr 0076B000 Size      100
          ... with many dozen more x'100' byte DFEs (free slots)
    .
    When browsing some of this storage, it looks like this:
    .
    Address      Offset     Hex
        00752100            00752140 3176E680 10000000 049B30D0
        00752110       +10  0380DB82 00752118 00000000 00000000
        00752120       +20  00002C31 4821DF68 00000000 7F20A010
        00752130       +30  00008FF4 00C000F6 00008FF4 000000F6
        00752140       +40  00752180 3176E680 10000000 049B30D0
        00752150       +50  0380DB82 00752158 00000000 00000000
        00752160       +60  00002C30 4821DF68 00000000 7F20A010
        00752170       +70  00008FF4 00C000F6 00008FF4 000000F6
        00752180       +80  007521C0 3176E680 10000000 049B30D0
        00752190       +90  0380DB82 00752198 00000000 00000000
        007521A0       +A0  00000C8B 4821DF68 00000000 7F20A010
        007521B0       +B0  00008FF4 00C000F6 00008FF4 000000F6
        007521C0       +C0  00752200 3176E680 10000000 049B30D0
        007521D0       +D0  0380DB82 007521D8 00000000 00000000
        007521E0       +E0  00000C8A 4821DF68 00000000 7F20A010
        007521F0       +F0  00008FF4 00C000F6 00008FF4 000000F6
        00752200      +100  00752240 3176E680 10000000 049B30D0
        00752210      +110  0380DB82 00752218 00000000 00000000
        00752220      +120  00000C87 4821DF68 00000000 7F20A010
        00752230      +130  00008FF4 00C000F6 00008FF4 000000F6
        00752240      +140  00752280 3176E680 10000000 049B30D0
        00752250      +150  0380DB82 00752258 00000000 00000000
        00752260      +160  00000C86 4821DF68 00000000 7F20A010
        00752270      +170  00008FF4 00C000F6 00008FF4 000000F6
        00752280      +180  007522C0 3176E680 10000000 049B30D0
        00752290      +190  0380DB82 00752298 00000000 00000000
        007522A0      +1A0  00000C85 4821DF68 00000000 7F20A010
    .
    This appears to be a chain of some kind of x'40' byte blocks.
    The first
    word points to the next block, and so on.
    .
    These are actually SCB's. Looking at some of the CICS TCBs, the
    TCB+x'A0' will point to a chain of SCBs for DFHKESTX. Debug
    Tool XEIIN and XEIOUT Global User Exits EQANCXIN and EQANCXOU
    are active.
    .
    Application transactions are going through JVM DTC_Clean
    processing which drives EXEC CICS RETURN. DT's GLUEs are
    setting an ESTAE. CICS is then "fooled" into adding another
    CICS ESTAE on the TCB. Often this is an Open TCB ( T8 for
    example.)
    .
    Diagnosing the issue:
    .
    To inspect this chain, get the address of the MVS TCBs for some
    of the T8 KTCBs in CICS. Format out this TCB using the
    following IPCS command:
    .
    CBF xxxxxxxx ASID(X'yyyy') STR(TCB)
    .
    replacing 'xxxxxxxx' with the address of the MVS TCB and 'yyyy'
    with the hex ASID for the CICS region.
    .
    In the output, a field labeled 'STAB' is the starting address
    for the SCBs. It will look similar to this:
    .
    STAB..... 00767A00
    .
    See how many are in the chain by taking that address and
    issuing the RUNCHAIN command, as in
    .
    RUNC ADDRESS(00767A00) LINK(0:3) LENGTH(X'20') CHAIN(99999)
    DISP VERIFY
    .
    In the resulting output, max to the bottom and IPCS will tell
    you how many SCB control blocks are in the chain:
    .
    BLS18094I 35,132 blocks processed
    .
    Normally this should only be a handful. In the above case,
    there are over 35 thousand of them. This is why all the storage
    is being chewed up.
    .
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED: Debug Tool 13.1 users who have the problems  *
    *                 described in the Problem Description.        *
    ****************************************************************
    * PROBLEM DESCRIPTION: AbendS878 occurs with Debug Tool in     *
    *                      CICS JVM environment due to SCB leak.   *
    *                      (PI40953 at 13.1)                       *
    *                                                              *
    *                      The current execution line does not     *
    *                      move when stepping through a large      *
    *                      application where the DSA chain         *
    *                      exceeds 100 save areas.                 *
    *                      Instead, line 1 is constantly           *
    *                      highlighted and the QUERY LOCATION      *
    *                      command indicated the program is at     *
    *                      line 0.                                 *
    *                      (PI41131 at 12.1)                       *
    *                                                              *
    *                      AbendS0C1 from entry @@DPIFN1 when      *
    *                      using z/OS 1.13 LE and debugging a C    *
    *                      or C++ program.                         *
    ****************************************************************
    * RECOMMENDATION: Installations that need these                *
    *                 problem fixes should install this service.   *
    ****************************************************************
    Miscellaneous service.
    

Problem conclusion

  • Service available.
    

Temporary fix

Comments

APAR Information

  • APAR number

    PI40953

  • Reported component name

    DEBUG TOOL Z/OS

  • Reported component ID

    5655Q1000

  • Reported release

    D10

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2015-05-13

  • Closed date

    2015-05-27

  • Last modified date

    2019-03-12

  • APAR is sysrouted FROM one or more of the following:

  • APAR is sysrouted TO one or more of the following:

    UI27973

Modules/Macros

  • EQA00ABE EQA00AIO EQA00CIC EQA00CND EQA00NMU EQA00OHH EQA0CINF
    EQA0SCL1 EQA0SCL2 EQA0SRP1 EQA0SRP2 EQA10PRC EQA80NMR EQA80VER
    EQAAFSPS EQADCCN0 EQALMA   EQANCCSE EQANCDBG EQANCLDE EQANCREL
    EQANCXEI EQANMDBG EQARCCDA EQARCDBG EQARCEXP EQARCHEX EQARCI3E
    EQARCL4  EQARCOBD EQARCPDC EQARCTRC EQARCVND EQAYSMMN
    

Fix information

  • Fixed component name

    DEBUG TOOL Z/OS

  • Fixed component ID

    5655Q1000

Applicable component levels

  • RD10 PSY UI27973

       UP15/05/29 P F505

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:
12 March 2019