RFR(MS): 8222072: JVMTI GenerateEvents() sends CompiledMethodLoad events to wrong jvmtiEnv

[serguei.spitsyn at oracle.com]

Hi Jc,

Thank you a lot for looking at this!

On 4/9/19 9:29 AM, Jean Christophe Beyler wrote:
> Hi Serguei,
>
> I saw a nit here:
>
> http://cr.openjdk.java.net/~sspitsyn/webrevs/2019/8222072-jvmti-GenerateEvents.1/test/hotspot/jtreg/serviceability/jvmti/GenerateEvents/MyPackage/GenerateEventsTest.java.html 
> <http://cr.openjdk.java.net/%7Esspitsyn/webrevs/2019/8222072-jvmti-GenerateEvents.1/test/hotspot/jtreg/serviceability/jvmti/GenerateEvents/MyPackage/GenerateEventsTest.java.html>
>
> arei -> are

Nice catch, fixed.

> - I'm not sure you needed two files for the agents, you could have 
> re-used some of the code and just called twice GetEnv but that is a 
> detail.

Right.
I initially wanted to use this way but then decided to use two real 
agent libraries.
Wanted to exercise this path.

> - I thought JNIEnv was not supposed to be really kept because it 
> should not be used by another thread, is there not a risk that you are 
> doing that? It doesn't look like it but I've been surprised in the past

You are right.
Tried to fix it in new webrev version below.


> - Isn't there a chance that your second agent gets a normal 
> JVMTI_EVENT_COMPILED_METHOD_LOAD before the GenerateEvents call and 
> increments its counter?
>    - I guess we'd see if it becomes flaky at some point? :)
Yes, it is expected.
But they should be posted on threads other than Main thread.
The callback should ignore them.


The updated fix version is:
http://cr.openjdk.java.net/~sspitsyn/webrevs/2019/8222072-jvmti-GenerateEvents.2/


Thanks!
Serguei

>
> Thanks!
> Jc
>
>
> On Mon, Apr 8, 2019 at 12:29 PM serguei.spitsyn at oracle.com 
> <mailto:serguei.spitsyn at oracle.com> <serguei.spitsyn at oracle.com 
> <mailto:serguei.spitsyn at oracle.com>> wrote:
>
>     Please, review a fix for:
>     https://bugs.openjdk.java.net/browse/JDK-8222072
>
>     Webrev:
>     http://cr.openjdk.java.net/~sspitsyn/webrevs/2019/8222072-jvmti-GenerateEvents.1/
>     <http://cr.openjdk.java.net/%7Esspitsyn/webrevs/2019/8222072-jvmti-GenerateEvents.1/>
>
>
>     Summary:
>       The JVMTI GenerateEvents() must send CompiledMethodLoad events
>     only to the agent which called it.
>       However, it sends events to all agents (jvmti environements)
>     which violates the JVMTI spec.
>       The webrev above fixes this issue and adds new jtreg test:
>         test/hotspot/jtreg/serviceability/jvmti/GenerateEvents
>
>
>     Testing:
>       Mach5 submission for:
>        - JVMTI tests: open/test/hotspot/jtreg/vmTestbase/nsk/jvmti
>     - new test: test/hotspot/jtreg/serviceability/jvmti/GenerateEvents
>
>     Thanks,
>     Serguei
>
>
>
> -- 
>
> Thanks,
> Jc

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