Github user benoyantony commented on the issue:
https://github.com/apache/zeppelin/pull/1778
When a note is run as by scheduler, thread T1 calls Note.runAll() and lock
on the paragraphs is acquired. Later, T1 tries to obtain locks on paragraphs
of other notes as part of status update. If scheduler starts running another
note using a different thread, this sequence will result in deadlock.
T1 -> locks N1.paragraphs , needs to obtain N2.paragraphs as part of
broadcastUpdateNotebookJobInfo
T2-> locks N2.paragraphs , needs to obtain N1.paragraphs as part of
broadcastUpdateNotebookJobInfo
T1 is waiting for N2.paragraphs holding lock on N1.paragraphs.
T2 is waiting for N1.paragraphs holding lock on N2.paragraphs.
The relevant thread dump is below:
"DefaultQuartzScheduler_Worker-6":
at org.apache.zeppelin.notebook.Note.getParagraphs(Note.java:537)
- waiting to lock <0x00000000c06cb168> (a java.util.ArrayList)
at
org.apache.zeppelin.notebook.Notebook.getJobListByUnixTime(Notebook.java:734)
at
org.apache.zeppelin.socket.NotebookServer.broadcastUpdateNotebookJobInfo(NotebookServer.java:423)
at
org.apache.zeppelin.socket.NotebookServer$ParagraphListenerImpl.afterStatusChange(NotebookServer.java:1468)
at org.apache.zeppelin.scheduler.Job.setStatus(Job.java:150)
at
org.apache.zeppelin.scheduler.RemoteScheduler.submit(RemoteScheduler.java:148)
at org.apache.zeppelin.notebook.Note.run(Note.java:510)
at org.apache.zeppelin.notebook.Note.runAll(Note.java:484)
- locked <0x00000000c071ad00> (a java.util.ArrayList)
at
org.apache.zeppelin.notebook.Notebook$CronJob.execute(Notebook.java:786)
at org.quartz.core.JobRunShell.run(JobRunShell.java:202)
at
org.quartz.simpl.SimpleThreadPool$WorkerThread.run(SimpleThreadPool.java:573)
- locked <0x00000000c0864798> (a java.lang.Object)
"DefaultQuartzScheduler_Worker-7":
at org.apache.zeppelin.notebook.Note.getParagraphs(Note.java:537)
- waiting to lock <0x00000000c071ad00> (a java.util.ArrayList)
at
org.apache.zeppelin.notebook.Notebook.getJobListByUnixTime(Notebook.java:734)
at
org.apache.zeppelin.socket.NotebookServer.broadcastUpdateNotebookJobInfo(NotebookServer.java:423)
at
org.apache.zeppelin.socket.NotebookServer$ParagraphListenerImpl.afterStatusChange(NotebookServer.java:1468)
at org.apache.zeppelin.scheduler.Job.setStatus(Job.java:150)
at
org.apache.zeppelin.scheduler.RemoteScheduler.submit(RemoteScheduler.java:148)
at org.apache.zeppelin.notebook.Note.run(Note.java:510)
at org.apache.zeppelin.notebook.Note.runAll(Note.java:484)
- locked <0x00000000c06cb168> (a java.util.ArrayList)
at
org.apache.zeppelin.notebook.Notebook$CronJob.execute(Notebook.java:786)
at org.quartz.core.JobRunShell.run(JobRunShell.java:202)
at
org.quartz.simpl.SimpleThreadPool$WorkerThread.run(SimpleThreadPool.java:573)
- locked <0x00000000c0864a98> (a java.lang.Object)
Found 1 deadlock.
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