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  1. JDK
  2. JDK-6275598

CMS heap verification can assert (false positive), especially when perm gen collection disabled

    Details

    • Type: Bug
    • Status: Resolved
    • Priority: P3
    • Resolution: Fixed
    • Affects Version/s: 6
    • Fix Version/s: 6
    • Component/s: hotspot
    • Labels:
    • Subcomponent:
      gc
    • Introduced In Build:
      1.4.1
    • Introduced In Version:
    • Resolved In Build:
      b92
    • CPU:
      generic
    • OS:
      generic

      Description

      Nightly test failure on 5/24:

      gc/64bit/quicklook/largeheap/GC32BitRange

      http://vmsqe.sfbay/nightly/mantis/DTWS/results/05-23-05/ServerVM/Solsparc/mixed/Gc_Baseline-Xinc/vm.gc-NIGHTLY-Gc_Baseline-Xinc-ServerVM-mixed-Solsparc-2005-05-24-07-35-33/analysis.html

      When part of the heap has been swept and the remainder of the
      heap that has not yet been swept has references to these
      swept up objects from now-dead-but-not-yet swept objects,
      we can get false assertions. The cross-section of
      vulnerability increases when perm gen collection is
      turned off or if we use incremental CMS.

      We could explore having the sweeper mark the dead objects in
      perm gen specially (when perm gen collection is not enabled
      and we are running a debug jvm) so that they are skipped during
      verification. We should make use of the CMS bit map
      to determine object liveness during verification
      that happens during a sweep.

      ###@###.### 2005-05-25 18:10:51 GMT

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            • Assignee:
              iveresov Igor Veresov
              Reporter:
              ysr Y. Ramakrishna
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                Updated:
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