Lucene - Core
  1. Lucene - Core
  2. LUCENE-5573

Deadlock during class loading/ initialization

    Details

    • Type: Bug Bug
    • Status: Closed
    • Priority: Major Major
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 4.8, Trunk
    • Component/s: None
    • Labels:
      None
    • Lucene Fields:
      New

      Description

      It's always worth looking into those randomized failures.

      http://builds.flonkings.com/job/Lucene-trunk-Linux-Java7-64-test-only/81259/console

      Log quote:

      [junit4]   2> ==== jstack at approximately timeout time ====
         [junit4]   2> "Lucene Merge Thread #0" ID=25 RUNNABLE
         [junit4]   2> 	at org.apache.lucene.codecs.lucene45.Lucene45DocValuesProducer.getSortedSet(Lucene45DocValuesProducer.java:541)
         [junit4]   2> 	at org.apache.lucene.codecs.perfield.PerFieldDocValuesFormat$FieldsReader.getSortedSet(PerFieldDocValuesFormat.java:285)
         [junit4]   2> 	at org.apache.lucene.index.SegmentReader.getSortedSetDocValues(SegmentReader.java:500)
         [junit4]   2> 	at org.apache.lucene.index.SegmentMerger.mergeDocValues(SegmentMerger.java:204)
         [junit4]   2> 	at org.apache.lucene.index.SegmentMerger.merge(SegmentMerger.java:119)
         [junit4]   2> 	at org.apache.lucene.index.IndexWriter.mergeMiddle(IndexWriter.java:4068)
         [junit4]   2> 	at org.apache.lucene.index.IndexWriter.merge(IndexWriter.java:3664)
         [junit4]   2> 	at org.apache.lucene.index.ConcurrentMergeScheduler.doMerge(ConcurrentMergeScheduler.java:405)
         [junit4]   2> 	at org.apache.lucene.index.ConcurrentMergeScheduler$MergeThread.run(ConcurrentMergeScheduler.java:482)
         [junit4]   2> 
         [junit4]   2> "TEST-TestLucene45DocValuesFormat.testSortedSetVariableLengthVsUninvertedField-seed#[7362FE36DE729D42]" ID=23 RUNNABLE
         [junit4]   2> 	at org.apache.lucene.index.SortedSetDocValues.<clinit>(SortedSetDocValues.java:72)
         [junit4]   2> 	at org.apache.lucene.index.DocTermOrds.iterator(DocTermOrds.java:767)
         [junit4]   2> 	at org.apache.lucene.search.FieldCacheImpl.getDocTermOrds(FieldCacheImpl.java:1214)
         [junit4]   2> 	at org.apache.lucene.index.BaseDocValuesFormatTestCase.doTestSortedSetVsUninvertedField(BaseDocValuesFormatTestCase.java:2342)
         [junit4]   2> 	at org.apache.lucene.index.BaseDocValuesFormatTestCase.testSortedSetVariableLengthVsUninvertedField(BaseDocValuesFormatTestCase.java:2375)
         [junit4]   2> 	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
         [junit4]   2> 	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
         [junit4]   2> 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
         [junit4]   2> 	at java.lang.reflect.Method.invoke(Method.java:606)
         [junit4]   2> 	at com.carrotsearch.randomizedtesting.RandomizedRunner.invoke(RandomizedRunner.java:1617)
         [junit4]   2> 	at com.carrotsearch.randomizedtesting.RandomizedRunner$6.evaluate(RandomizedRunner.java:826)
         [junit4]   2> 	at com.carrotsearch.randomizedtesting.RandomizedRunner$7.evaluate(RandomizedRunner.java:862)
         [junit4]   2> 	at com.carrotsearch.randomizedtesting.RandomizedRunner$8.evaluate(RandomizedRunner.java:876)
         [junit4]   2> 	at org.apache.lucene.util.TestRuleSetupTeardownChained$1.evaluate(TestRuleSetupTeardownChained.java:50)
         [junit4]   2> 	at org.apache.lucene.util.TestRuleFieldCacheSanity$1.evaluate(TestRuleFieldCacheSanity.java:51)
         [junit4]   2> 	at org.apache.lucene.util.AbstractBeforeAfterRule$1.evaluate(AbstractBeforeAfterRule.java:46)
         [junit4]   2> 	at com.carrotsearch.randomizedtesting.rules.SystemPropertiesInvariantRule$1.evaluate(SystemPropertiesInvariantRule.java:55)
         [junit4]   2> 	at org.apache.lucene.util.TestRuleThreadAndTestName$1.evaluate(TestRuleThreadAndTestName.java:49)
         [junit4]   2> 	at org.apache.lucene.util.TestRuleIgnoreAfterMaxFailures$1.evaluate(TestRuleIgnoreAfterMaxFailures.java:70)
         [junit4]   2> 	at org.apache.lucene.util.TestRuleMarkFailure$1.evaluate(TestRuleMarkFailure.java:48)
         [junit4]   2> 	at com.carrotsearch.randomizedtesting.rules.StatementAdapter.evaluate(StatementAdapter.java:36)
         [junit4]   2> 	at com.carrotsearch.randomizedtesting.ThreadLeakControl$StatementRunner.run(ThreadLeakControl.java:359)
         [junit4]   2> 	at com.carrotsearch.randomizedtesting.ThreadLeakControl.forkTimeoutingTask(ThreadLeakControl.java:783)
         [junit4]   2> 	at com.carrotsearch.randomizedtesting.ThreadLeakControl$3.evaluate(ThreadLeakControl.java:443)
         [junit4]   2> 	at com.carrotsearch.randomizedtesting.RandomizedRunner.runSingleTest(RandomizedRunner.java:835)
         [junit4]   2> 	at com.carrotsearch.randomizedtesting.RandomizedRunner$3.evaluate(RandomizedRunner.java:737)
         [junit4]   2> 	at com.carrotsearch.randomizedtesting.RandomizedRunner$4.evaluate(RandomizedRunner.java:771)
         [junit4]   2> 	at com.carrotsearch.randomizedtesting.RandomizedRunner$5.evaluate(RandomizedRunner.java:782)
         [junit4]   2> 	at org.apache.lucene.util.AbstractBeforeAfterRule$1.evaluate(AbstractBeforeAfterRule.java:46)
         [junit4]   2> 	at org.apache.lucene.util.TestRuleStoreClassName$1.evaluate(TestRuleStoreClassName.java:42)
         [junit4]   2> 	at com.carrotsearch.randomizedtesting.rules.SystemPropertiesInvariantRule$1.evaluate(SystemPropertiesInvariantRule.java:55)
         [junit4]   2> 	at com.carrotsearch.randomizedtesting.rules.NoShadowingOrOverridesOnMethodsRule$1.evaluate(NoShadowingOrOverridesOnMethodsRule.java:39)
         [junit4]   2> 	at com.carrotsearch.randomizedtesting.rules.NoShadowingOrOverridesOnMethodsRule$1.evaluate(NoShadowingOrOverridesOnMethodsRule.java:39)
         [junit4]   2> 	at com.carrotsearch.randomizedtesting.rules.StatementAdapter.evaluate(StatementAdapter.java:36)
         [junit4]   2> 	at org.apache.lucene.util.TestRuleAssertionsRequired$1.evaluate(TestRuleAssertionsRequired.java:43)
         [junit4]   2> 	at org.apache.lucene.util.TestRuleMarkFailure$1.evaluate(TestRuleMarkFailure.java:48)
         [junit4]   2> 	at org.apache.lucene.util.TestRuleIgnoreAfterMaxFailures$1.evaluate(TestRuleIgnoreAfterMaxFailures.java:70)
         [junit4]   2> 	at org.apache.lucene.util.TestRuleIgnoreTestSuites$1.evaluate(TestRuleIgnoreTestSuites.java:55)
         [junit4]   2> 	at com.carrotsearch.randomizedtesting.rules.StatementAdapter.evaluate(StatementAdapter.java:36)
         [junit4]   2> 	at com.carrotsearch.randomizedtesting.ThreadLeakControl$StatementRunner.run(ThreadLeakControl.java:359)
      

      Robert looked into it and was wtf'd, quote:

      what happened here...
      

      I looked into it and was wtf'd, quote (from my head):

      wtf?!
      

      I looked deeper at the code and it's a beautiful and classic class loading deadlock. I don't think I've seen an example of this in real life ever, except for this one case.

      Problem description.

      1. Thread A attempts to return a new instance of RandomAccessOrds:

      return new RandomAccessOrds() {
      

      RandomAccessOrds extends SortedSetDocValues and has a final static field which in turn loads RandomAccessOrds (circular reference).

      2. Thread B attempts to create:

      private class Iterator extends SortedSetDocValues {
      

      3. If thread B starts loading SortedSetDocValues, it blocks other threads from doing so. If, at the same time, thread A starts loading RandomAccessOrds then thread A will eventually attempt to initialize SortedSetDocValues and both will wait for each other indefinitely.

      I attach a simpler example that does the same as a POC.

      1. A.java
        0.9 kB
        Dawid Weiss
      2. C.java
        0.9 kB
        Dawid Weiss
      3. LUCENE-5573.patch
        34 kB
        Robert Muir
      4. Main.java
        1 kB
        Dawid Weiss
      5. X.java
        1 kB
        Dawid Weiss

        Activity

        No work has yet been logged on this issue.

          People

          • Assignee:
            Robert Muir
            Reporter:
            Dawid Weiss
          • Votes:
            0 Vote for this issue
            Watchers:
            7 Start watching this issue

            Dates

            • Created:
              Updated:
              Resolved:

              Development