IJ32524: CRASH IN MM_SCAVENGERDELEGATE::SIGNALTHREADSTOFLUSHCACHES

APAR status

• Closed as program error.

Error description

• Error Message: GPF is received
  .
  Stack Trace:
  MM_ScavengerDelegate::signalThreadsToFlushCaches(MM_EnvironmentB
  ase*)+0xd4
  
  MM_Scavenger::shouldDoFinalNotify(MM_EnvironmentStandard*)+0x5e
  
  MM_Scavenger::getNextScanCache(MM_EnvironmentStandard*)+0xc00
      MM_Scavenger::workThreadScan(MM_EnvironmentStandard*)+0x41e
      MM_ConcurrentScavengeTask::run(MM_EnvironmentBase*)+0x78
  
  MM_ParallelDispatcher::slaveEntryPoint(MM_EnvironmentBase*)+0x11
  4
      dispatcher_thread_proc2(OMRPortLibrary*,void*)+0x19a
      omrsig_protect+0x458
      dispatcher_thread_proc+0x6c
  .
  

Local fix

Problem summary

• The issue is caused due to incorrect lock synchronization. In
  Concurrent Scavenger, when close to terminating concurrent phase
  and signaling mutator threads to flush their copy caches, prior
  to thread iteration thread lock is acquired. However, it's taken
  after the iterator construction. The main thread may race and
  terminate before we acquire the lock and start iteration.
  PR: https://github.com/eclipse-openj9/openj9/pull/12566
  

Problem conclusion

• The JVM has been updated to construct the iterator after
  acquiring the lock.
  .
  This APAR will be fixed in the following Java Releases:
     8    SR6 FP35  (8.0.6.35)
  .
  Contact your IBM Product's Service Team for these Service
  Refreshes and Fix Packs.
  For those running stand-alone, information about the available
  Service Refreshes and Fix Packs can be found at:
             https://www.ibm.com/developerworks/java/jdk/
  

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

• R270 PSY

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