PH58090: DEADLOCK DURING DB2 HADR FAILOVER

APAR status

• Closed as program error.

Error description

• From javacore we see the deadlock is between below 2 threads/
  
  Both threads have locked on object required by the other and
  thus a permanent hang condition.
  
  1LKDEADLOCK    Deadlock detected !!!
  
  NULL           ---------------------
  
  NULL
  
  2LKDEADLOCKTHR  Thread "ET4_EXTRACTOR:OPM.PDO_FSE_EWR (PDO)2
  #890" (0x0000000034A74D00)
  
  3LKDEADLOCKWTR    is waiting for:
  
  4LKDEADLOCKMON      sys_mon_t:0x00000100378F0FE8 infl_mon_t:
  0x00000100378F1038:
  
  4LKDEADLOCKOBJ      java/lang/Integer@0x000000070948B888
  
  3LKDEADLOCKOWN    which is owned by:
  
  2LKDEADLOCKTHR  Thread "ET4_EXTRACTOR:OPM.PDO_FAMILY (PDOW)
  #465" (0x0000000034A7CA00)
  
  3LKDEADLOCKWTR    which is waiting for:
  
  4LKDEADLOCKMON      sys_mon_t:0x00000100378F0BC0 infl_mon_t:
  0x00000100378F0C10:
  
  4LKDEADLOCKOBJ      java/lang/Integer@0x000000070948B438
  
  3LKDEADLOCKOWN    which is owned by:
  
  2LKDEADLOCKTHR  Thread "ET4_EXTRACTOR:OPM.PDO_FSE_EWR (PDO)2
  #890" (0x0000000034A74D00)
  
  
  Thread "ET4_EXTRACTOR:OPM.PDO_FAMILY (PDOW) #465" j2c code:
  
  com/ibm/ejs/j2c/PoolManager.fatalErrorNotification(PoolManager.
  java:1997)
  
  has a lock on:
  
  entered lock: java/lang/Integer@0x000000070948B8B8, entry count:
  1
  
  and thus thread: "ET4_EXTRACTOR:OPM.PDO_FSE_EWR (PDO)2 #890"
  cannot move as it needs it.
  
  
  However, "ET4_EXTRACTOR:OPM.PDO_FSE_EWR (PDO)2 #890" j2c code
  
  com/ibm/ejs/j2c/PoolManager.reserve(PoolManager.java:3679)
  
  has a lock on
  
  
  entered lock: java/lang/Integer@0x000000070948B438, entry
  count: 1
  
  which is required by thread "ET4_EXTRACTOR:OPM.PDO_FAMILY (PDOW)
  #465" and cannot move as it needs it.
  

Local fix

• N/A
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:  All users of IBM WebSphere Application      *
  *                  Server                                      *
  *                  user of connection pooling.                 *
  ****************************************************************
  * PROBLEM DESCRIPTION: A dead lock may occur during connection *
  *                      error processing and purging the        *
  *                      connection pool                         *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  A java core stack containing
  PoolManager.fatalErrorNotification(PoolManager.
  java:1997) and deadlocked with another thread would identify
  this
  problem.
  

Problem conclusion

• The unnecessary synchronization in processing failing connection
  was removed.
  
  The fix for this APAR is targeted for inclusion in fix pack
  8.5.5.26 and 9.0.5.19. For more information, see 'Recommended
  Updates for WebSphere Application Server':
  https://www.ibm.com/support/pages/node/715553
  

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

  WEBS APP SERV N

• Fixed component ID

  5724H8800

Applicable component levels