RFR: 8256314: JVM TI GetCurrentContendedMonitor is implemented incorrectly

[Alan Bateman]

On Wed, 21 Feb 2024 10:28:49 GMT, Serguei Spitsyn <sspitsyn at openjdk.org> wrote:

> The implementation of the JVM TI `GetCurrentContendedMonitor` does not match the spec. It can sometimes return an incorrect information about the contended monitor. Such a behavior does not match the function spec. 
> With this update the `GetCurrentContendedMonitor` is returning the monitor only when the specified thread is waiting to enter or re-enter the monitor, and the monitor is not returned when the specified thread is waiting in the `java.lang.Object.wait` to be notified.
> 
> The implementation of the JDWP `ThreadReference.CurrentContendedMonitor` command is based and depends on this JVMTI function. The command was both specified incorrectly and had an incorrect behavior. The fix slightly corrects the JDWP spec to make it right (the JDWP implementation has been fixed by the JVM TI update). Please, see and review the related CSR and Release-Note.
> 
> CSR: [8326024](https://bugs.openjdk.org/browse/JDK-8326024): JVM TI GetCurrentContendedMonitor is implemented incorrectly
> RN:   [8326038](https://bugs.openjdk.org/browse/JDK-8326038): Release Note: JVM TI GetCurrentContendedMonitor is implemented incorrectly
> 
> Testing:
>  - tested with the mach5 tiers 1-6

Are you planning to update ThreadReference::currentContendedMonitor method description too?

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PR Comment: https://git.openjdk.org/jdk/pull/17944#issuecomment-1959636693