PK40828: TCPIPSERVICE PORT HANGS ON CLOSE

APAR status

• Closed as duplicate of another APAR.

Error description

• When an application issues a close on the port, it sometimes
  goes into 'closing' status and won't recover.  Looking at the
  sockets domain, the port is in a status of CLOSING eventhough
  the task is no longer present.  This problem is similar to
  APAR PQ92551.  The hanging socket has an element on its reserve
  chain for the task 12937 (which is not present in the dump).
  
  The socket object's notify_action is soso_notify_socket_closed.
  This implies that before SOCKETCLOSE could kick in, the client
  closed its end of the socket connection.
  When this happens, DFHWBSO is notified. It notes the closure
  and returns, leaving it up the soso_notify_mainline to handle
  the closure and deletion of the socket. A Socket.relinquish call
  is made. This detects that there is apparently another task
  still using the socket (task# 12937 - which was already
  terminated).
  So the socket is not deleted as expected.
  Additional Symptoms: DFHSO0126 W "An attempt to create a
  socket has failed because the MAXSOCKETS limit has been
  reached."  This can happen as, over time, usused and closed
  TCPIP connections remain active intermittently.  Such
  connections count towards the MAXSOCKETS limit.  In a dump,
  these connections look like this:
  (Here is the left half of the 1st Sockets summary:)
  TOKEN    FLAGS  Send ECB Recv ECB I/O      Dom
  ________________________________________________
  011A008D GT N   00000000 00000000            34
  010300F2 GT N   00000000 00000000            34
  01080516 GT N   00000000 00000000            34
  01330059 GT N   00000000 00000000            34
  016700A4 GT N   00000000 00000000            34
  .......... and here is the matching right half......
  Gate Remote IPAddr   Port  Task  AIO Err
  _________________________________________
    20 999.999.99.999  nnnnn    1   CLOSED
    20 999.999.99.999  nnnnn    1   CLOSED
    20 999.999.99.999  nnnnn    1   CLOSED
    20 999.999.99.999  nnnnn    1   CLOSED
    20 999.999.99.999  nnnnn    1   CLOSED
  ------------------------------------------
  Each of these connections shows that it is still
  associated with 1 task.  But the last task that used
  these connections is long gone.
  

Local fix

Problem summary

Problem conclusion

Temporary fix

Comments

• This APAR is being closed with a closing code of DUP. The fix
  will be provided by APAR PK33200.
  

APAR Information

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

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

Fix information

Applicable component levels