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  1. Lucene - Core
  2. LUCENE-9661

Another classloader deadlock?

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    Details

    • Type: Bug
    • Status: Resolved
    • Priority: Blocker
    • Resolution: Fixed
    • Affects Version/s: 8.0, master (9.0)
    • Fix Version/s: 8.x, master (9.0), 8.8
    • Component/s: None
    • Labels:
      None
    • Lucene Fields:
      New

      Description

      The java processes spawned by our Lucene nightly benchmarks sometimes randomly hang, apparently while loading classes across threads, under contention.

      I've opened this luceneutil issue with some details, but Uwe Schindler suggested I open an issue here too since he has been seeing this in CI builds too.

      It is rare, maybe once a week in the nightly benchmarks (which spawn many java processes with many threads across 128 CPU cores).  It is clearly a deadlock – when it strikes, the process hangs forever until I notice and kill -9 it.  I posted a coupled jstacks in the issue above.

      Robert Muir suggested using classcycle to maybe statically dig into possible deadlocks ... I have not tried that yet.

        Attachments

        1. deadlock_test.patch
          9 kB
          Namgyu Kim
        2. deadlock inspections.jpg
          150 kB
          Namgyu Kim
        3. intellij inspection results.html
          52 kB
          David Smiley

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              • Assignee:
                danmuzi Namgyu Kim
                Reporter:
                mikemccand Michael McCandless
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