APAR status
Closed as program error.
Error description
Error Message: The JVM hangs while multiple threads are parked on the same lock (e.g. a java/util/concurrent/locks/ReentrantLock$NonfairSync object). The thread that is supposed to wake all the parked threads is also incorrectly stuck in the parked state so all the threads remain parked and never wake up. . Stack Trace: sun/misc/Unsafe.park java/util/concurrent/locks/LockSupport.park java/util/concurrent/locks/AbstractQueuedSynchronizer.parkAndChe ckInterrupt java/util/concurrent/locks/AbstractQueuedSynchronizer.acquireQue ued java/util/concurrent/locks/AbstractQueuedSynchronizer.acquire java/util/concurrent/locks/ReentrantLock$NonfairSync.lock java/util/concurrent/locks/ReentrantLock.lock java/util/concurrent/ArrayBlockingQueue.offer .
Local fix
Problem summary
The problem occurs when the Java code depends on volatile semantics to ensure that the volatile field updates are seen in different threads. The problem is caused by incorrect volatile field handling in JIT-compiled code. A memory fence for a volatile field is missing after a write operation due to incorrect JIT code generation. This issue affects z/OS and z/Linux, running on z9 or older hardware.
Problem conclusion
This defect will be fixed in: 5.0 SR15 6.0 SR12 6.0.1 SR3 7.0.0 SR2 . The JIT compiler has been updated to generate the memory fence if the field is found to be a volatile.
Temporary fix
Comments
APAR Information
APAR number
IV26972
Reported component name
JIT
Reported component ID
620700124
Reported release
260
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2012-08-24
Closed date
2012-08-24
Last modified date
2012-10-10
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
JIT
Fixed component ID
620700124
Applicable component levels
R260 PSY
UP
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Document Information
Modified date:
10 October 2012