PH15294: ULB HANG WITH MULTIPLE CONCURRENT ARP RESPONSES

9.0.5.2: WebSphere Application Server traditional Version 9.0.5 Fix Pack 2
8.5.5.17: WebSphere Application Server V8.5.5 Fix Pack 17
9.0.5.3: WebSphere Application Server traditional Version 9.0.5 Fix Pack 3

APAR status

• Closed as program error.

Error description

• System hang may occur on AIX.
  

Local fix

• N/A
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:  IBM WebSphere Application Server Load       *
  *                  Balancer for IPv4 and IPv6 users on AIX     *
  ****************************************************************
  * PROBLEM DESCRIPTION: System may hang.                        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  If a dump is taken during the hang situation, multiple CPUs
  will show stacks containing os_mutex_lock, os_packetxmit,
  lbarp_send near the top on at least two CPUs.
  

Problem conclusion

• The Load Balancer for IPv4 and IPv6 was enabling a lock before
  transmitted a packet and no kernel locks should be held open
  when transmitting a packet. Code has been corrected to release
  the lock before transmitting.
  
  Fix pack levels:
  8.5.5.17
  9.0.5.2
  

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:

Fix information

• Fixed component name

  WS EDGE LB IPV4

• Fixed component ID

  5724H8812

Applicable component levels

• R850 PSY

     UP

• R900 PSY

     UP