IV44956: DEADLOCK IN CLASS THREADGROUP

APAR status

• Closed as program error.

Error description

• Error Message: A Javacore file generated at the time of the
  deadlock shows the following:
      1LKDEADLOCK    Deadlock detected !!!
      NULL           ---------------------
      NULL
      2LKDEADLOCKTHR  Thread "<Thread_1>" (0x04DB0A00)
      3LKDEADLOCKWTR    is waiting for:
      4LKDEADLOCKMON      sys_mon_t:0x0493A70C infl_mon_t:
  0x0493A744:
      4LKDEADLOCKOBJ
  java/lang/ThreadGroup$ChildrenThreadsLock@0x274E16A0/0x274E16AC:
      3LKDEADLOCKOWN    which is owned by:
      2LKDEADLOCKTHR  Thread "<Thread_2>" (0x5CC38900)
      3LKDEADLOCKWTR    which is waiting for:
      4LKDEADLOCKMON      sys_mon_t:0x56337710 infl_mon_t:
  0x56337748:
      4LKDEADLOCKOBJ
  java/lang/ThreadGroup$ChildrenGroupsLock@0x11184960/0x1118496C:
      3LKDEADLOCKOWN    which is owned by:
      2LKDEADLOCKTHR  Thread "Thread_1" (0x04DB0A00)
  .
  Stack Trace: N/A
  .
  

Local fix

Problem summary

• The problem occurs when one thread is trying to destroy the
  ThreadGroup while another thread is enumerating the active
  threads using method such as ThreadGroup.activeCount(),
  ThreadGroup.enumerate() or ThreadGroup.list().
  

Problem conclusion

• This defect will be fixed in:
  6.0.0 SR15
  6.0.1 SR7
  7.0.0 SR6
  .
      The JVM has been updated to ensure that the locks in
  ThreadGroup are always acquired and released in the same order.
  

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

  J9 COMMON CODE

• Fixed component ID

  620700127

Applicable component levels

• R600 PSY

     UP

• R260 PSY

     UP