IZ91125: DUPLICATE SYN PACKETS CAUSE SOCKETS TO NEVER BE FREED APPLIES TO AIX 5300-12

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• There are two symptoms for this.  One is that memory will
  be used up and eventually network memory will be
  exhausted.
  The list of sockets of the free list will be large --
  often
  in the hundreds of thousands.  The other symptom is the
  statistic: "Connection dropped due to duplicate SYN
  packets" will be large.  Usually it is zero.  Note that
  if
  the system freezes and is rebooted, this count will be 0
  so in the snap it will be 0.  But issuing netstat -s
  using
  kdb from a dump of the system will provide the value at
  the time the system dump was forced (assuming a system
  dump is forced).
  

Local fix

Problem summary

• Customer system freezes. The network memory is exhausted and
  also the statistic: "Connection dropped due to duplicate SYN
  packets" was very large ( 744204).
  

Problem conclusion

• When we identify a packet as duplicate SYN and before
  dropping it, we will unref the socket ( of existing
  connection). Later when socket is closEd it will get closed
  without any issue.
  

Temporary fix

Comments

• 5300-10 - use AIX APAR IZ83149
  5300-11 - use AIX APAR IZ91126
  5300-12 - use AIX APAR IZ91125
  6100-03 - use AIX APAR IZ94544
  6100-04 - use AIX APAR IZ94537
  6100-05 - use AIX APAR IZ94531
  6100-06 - use AIX APAR IZ94528
  6100-06 - use AIX APAR IZ86972
  7100-01 - use AIX APAR IZ99505
  

APAR Information

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

  IZ81013

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

Fix information

• Fixed component name

  AIX 5.3

• Fixed component ID

  5765G0300

Applicable component levels

• R530 PSY U838600

     UP11/02/22 I 1000

PTF to Fileset Mapping

• U838600 bos.net.tcp.client 5.3.12.3