RFR: 8332259: JvmtiTrace::safe_get_thread_name fails if current thread is in native state [v4]

[Leonid Mesnik]

On Fri, 17 May 2024 22:31:32 GMT, Leonid Mesnik <lmesnik at openjdk.org> wrote:

>> The JvmtiTrace::safe_get_thread_name sometimes crashes when called while current thread is in native thread state.
>> 
>> It happens when thread_name is set for tracing from jvmti functions.
>> See:
>> https://github.com/openjdk/jdk/blob/master/src/hotspot/share/prims/jvmtiEnter.xsl#L649 
>> 
>> The setup is called and the thread name is used in tracing before the thread transition. There is no good location where this method could be called from vm thread_state only. Some functions like raw monitor enter/exit never transition in vm state. So sometimes it is needed to call this function from native thread state.
>> 
>> The change should affect JVMTI trace mode only (-XX:TraceJVMTI). 
>> 
>> Verified by running jvmti/jdi/jdb tests with tracing enabled.
>
> Leonid Mesnik has updated the pull request incrementally with one additional commit since the last revision:
> 
>   wrong thread state

I discussed the issue with @sspitsyn and after this, I updated the function to return something more descriptive in case we can't read thread state. (Easier to understand what happens.)

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PR Comment: https://git.openjdk.org/jdk/pull/19275#issuecomment-2136203620