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  1. JDK
  2. JDK-8247729

GetObjectMonitorUsage() might return inconsistent information

    Details

    • Type: Bug
    • Status: Resolved
    • Priority: P4
    • Resolution: Fixed
    • Affects Version/s: 16
    • Fix Version/s: 16
    • Component/s: hotspot
    • Labels:
      None
    • Subcomponent:
    • Resolved In Build:
      b03

      Description

      GetObjectMonitorUsage() JVMTI function is expected to return information which an accurate snapshot of the state of the monitor at some point in time, but it does not ensure that in the current implementation.

      This function is implemented to use JvmtiEnvBase::get_object_monitor_usage(). It tries to
      gather the relevant information without going to a safepoint, but under certain conditions it
      recognizes that going to a safepoint is necessary in order to gather stable information.
      Subsequent analysis has shown that the code paths where a safepoint is not used can
      result in unstable information being returned.

      See the discussion in serviceability-dev for more details:
      https://mail.openjdk.java.net/pipermail/serviceability-dev/2020-June/031876.html

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            • Assignee:
              ysuenaga Yasumasa Suenaga
              Reporter:
              ysuenaga Yasumasa Suenaga
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              Dates

              • Created:
                Updated:
                Resolved: