PQ06608: OFFLOAD FAILS WITH SYS3175 IN OFFSOCKD.EXE AND CAUSES THE OFFLOAD BOX TO HANG. TCP STACK CANNOT RESTART THE LINK.

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• OFFLOAD box hangs with LED 4001 displayed.  Registers are as
  follows..
  SYS3175
  
  A PROGRAM GENERATED AN ACCESS VIOLATION AT 00014EAD.
  OFFSOCKD.EXE 0009:000000BD
  
  P1=00000000   P2=FFFFFFFF    P3=XXXXXXXX   P4=XXXXXXXX
  EAX=000001A7  EXBX=00000000  ECX=00000000  EDX=000078D0
  DS=00CF   DSACC=00F3   DSLIM=0000FCF7
  ES=0000   ESACC=****   ESLIM=********
  FS=150B   FSACC=00F3   FSLIM=00000030
  GS=0000   GSACC=****   GSLIM=********
  
  GS:EIP=004F:000000BD   CSACC=00FB   CSLIM=000022E7
  SS:ESP=00EF:0000806A   SSACC=00F3   SSLIM=0000DFFF
  
  EBD=0000806E   FLG=00012202
  .
  If the customer attempts to restart the CLAW link he receives
  the following messages.
  EZB4360E CLAW shutting down:
  EZB7042I    Device OFF1:
  EZB7043I       Type: CLAW, Status: Ready
  EZB7044I       Envelope queue size: 0
  EZB7105I       Address: 0930 Host name: TCPIP Adapter name: OS2T
                                                  Control task nam
  EZB4358I CLAW initializing:
  EZB7042I  Device OFF1:
  EZB7043I     Type: CLAW, Status: Not started
  EZB7044I     Envelope queue size: 0
  EZB7105I     Address: 0930 Host name: TCPIP Adapter name: OS2TCP
                                                  Control task nam
  EZB4275I CLAW device OFF1: Received Control Packet:
  EZB4374I    Sys Validate Resp: Vers=2,Corr=0,RC=0,WS name=OS2TCP
                        Host name=TCPIP,Read frame=4096, Write fra
  EZB4390I Claw device OFF1: System validate completed.
  EZB4275I CLAW device OFF1: Received Control Packet:
  EZB4376I    Conn Resp: Vers=2,Link ID=1,Corr=0,RC=0,WS appl=TCPI
                                                          Host app
  EZB4275I CLAW device OFF1: Received Control Packet:
  EZB4376I    Conn Resp: Vers=2,Link ID=2,Corr=0,RC=0,
                                             WS appl=API,Host appl
  EZB4275I CLAW device OFF1: Received Control Packet:
  EZB4377I    Conn Conf: Vers=2,Link ID=1,Corr=0,RC=0,
                                           WS appl=TCPIP,Host appl
  .
  The TCP/IP stack itself is not hung, but the OFFLOAD link cannot
  be restarted and therefore communications are lost.  Box has to
  be stopped and started to recover.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users of TCP/IP for MVS; Offload.        *
  ****************************************************************
  * PROBLEM DESCRIPTION: Trap D in OFFSOCKD.EXE during heavy     *
  *                      load.                                   *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  During heavy socket use. That is, more than 20 connections
  per second.  Offload can mis-queue a socket thread control
  structure.  It may be freed twice causing a TRAP D.
  

Problem conclusion

• OFFSOCKD.EXE has been changed to clear residual pointers in
  socket control blocks. If the pointers are zero the free routine
  ignores the block.
  
  This code is also known as HL97365 CSD
  * Cross Reference between External and Internal Names
  OFFSOB10 (OFFSOCKD)
  

Temporary fix

Comments

APAR Information

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

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

  PQ14292 PQ14307 PQ14308 PQ14309 UQ15913

Modules/Macros

• OFFSOB10
  

Fix information

• Fixed component name

  TCP/IP V3 MVS

• Fixed component ID

  5655HAL00

Applicable component levels

• RB10 PSY UQ15913

     UP98/04/06 I 1000

Fix is available

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