Details
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Bug
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Status: Open
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Major
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Resolution: Unresolved
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2.4.0
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None
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None
Description
I have a deadlock scenario where jstack shows 14 threads BLOCKED on the object monitor, and one other thread as the owner. The owning thread is not anywhere near that code - it's, in fact, setting in the thread pool waiting for work to do (owner and one blocked thread shown below for brevity):
"clrd-normalpri-13" Id=165 BLOCKED on java.text.SimpleDateFormat@1b9ff8be owned by "clrd-normalpri-12" Id=164
at org.jclouds.date.internal.SimpleDateFormatDateService.rfc822DateParse(SimpleDateFormatDateService.java:103)
- blocked on java.text.SimpleDateFormat@1b9ff8be
at org.jclouds.blobstore.functions.ParseSystemAndUserMetadataFromHeaders.parseLastModifiedOrThrowException(ParseSystemAndUserMetadataFromHeaders.java:99)
at org.jclouds.blobstore.functions.ParseSystemAndUserMetadataFromHeaders.apply(ParseSystemAndUserMetadataFromHeaders.java:72)
at org.jclouds.s3.functions.ParseObjectMetadataFromHeaders.apply(ParseObjectMetadataFromHeaders.java:62)
at org.jclouds.s3.functions.ParseObjectFromHeadersAndHttpContent.apply(ParseObjectFromHeadersAndHttpContent.java:48)
at org.jclouds.s3.functions.ParseObjectFromHeadersAndHttpContent.apply(ParseObjectFromHeadersAndHttpContent.java:34)
at org.jclouds.rest.internal.InvokeHttpMethod.invoke(InvokeHttpMethod.java:91)
at org.jclouds.rest.internal.InvokeHttpMethod.apply(InvokeHttpMethod.java:74)
...
Number of locked synchronizers = 1
- java.util.concurrent.ThreadPoolExecutor$Worker@39133244
"clrd-normalpri-12" Id=164 WAITING on java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject@f32283d
at sun.misc.Unsafe.park(Native Method)
- waiting on java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject@f32283d
at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175)
at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2039)
at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:442)
at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)
This issue is not easily reproduced, and frankly I can't understand how it can happen. The JVM is supposed to guarantee it doesn't, so I have no suggestions as to how one might fix it. SO question posted at: https://stackoverflow.com/questions/72117726/jclouds-multiple-threads-blocked-on-object-monitor-owned-by-thread-waiting-in-p - maybe someone out there has a clue.