PH47586: EDGE LOAD BALANCER CRASHES IN IBMLB2 FUNCTION LBLL_SELECT1_NL WITH AFFINITY CONFIGURED.

APAR status

• Closed as program error.

Error description

• A crash can occur with Load Balancer when affinity based
  forwarding is configured.
  Function calls on the stack willinclude:
  
  lbll_select1_nl
  _lbsel_at_getnewar
  lbsel_at_chooseserver
  _lbsel_ct_chooseserver
  _lbsel_ctat_choose
  
  Executor tracing shows: (? represents variable data)
  lb_linkedlist: wrong list, rc ????????.
  lb_sel_affinity: lbllrmnode error.
  lb_linkedlist: l,r,list ptrs not null,addnode_rhs_nl rc=2.
  lb_sel_affinity: add to at failed.
  pkt ? ? ?.?.?.? -> ?.?.?.? ?:? add to expirelist failed.
  

Local fix

• N/A
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:  IBM WebSphere Application Server Load       *
  *                  Balancer for IPv4 and IPv6 users with       *
  *                  affinity configured                         *
  ****************************************************************
  * PROBLEM DESCRIPTION: The executor may crash when affinity    *
  *                      based routing is configured in the      *
  *                      Load Balancer. The crash occurs in      *
  *                      the ibmlb2 module.                      *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  The executor module crashes when affinity based routing is
  configured and a client has multiple simultaneous open
  connections. After the crash occurs, all executor commands
  fail. On AIX, the system abends.
  

Problem conclusion

• Semaphore programming was corrected to prevent the affinity
  record from being altered by one thread when another thread is
  using the record.
  
  Fix levels:
    8.5.5.23
    9.0.5.14
  

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