Re: [RFA/JVMTI] Better env list locking

[Keith Seitz <keiths at redhat dot com>]

Tom Tromey wrote:

> Keith> Comments/questions/concerns?
>
> Can post_event or any callback it calls possibly throw an exception?
> If so that will leave the lock held.
>
> If not this is ok.  Thanks.

That's a really good question. The JVMTI specification does talk about 
dealing with exceptions that occur during the event callback, but 
nothing particularly definitive about whether a callback is allowed to 
throw an exception:

"Any exception thrown during the execution of an event callback can 
overwrite any current pending exception in the current application 
thread. Care must be taken to preserve a pending exception when an event 
callback makes a JNI call that might generate an exception."

From what I read into this, it sounds more like it is up to the agent 
to deal with exceptions properly, not the JVMTI implementation. But then 
perhaps a bit of defensive programming might not hurt? Catch any 
exceptions, release the lock, and rethrow the exception?

I don't really know. I could go either way, really. Your call, Mr. 
Maintainer. :-)

Keith