RFR: 8256382: Use try_lock for hs_err EventLog printing

[Thomas Stuefe]

On Wed, 25 Nov 2020 07:36:04 GMT, David Holmes <dholmes at openjdk.org> wrote:

> Don't we have to check not only VMError::is_error_reported, but that it is the current thread that is doing the reporting?
> 

You mean my proposal of just not locking altogether?
Its a calculated risk. The chance of someone printing out the even log concurrently to the hs-err reporter doing it is extremely low, and since we have secondary crash reporting the only risk we run is an interrupted error reporting step.

> I also think the Thread::current_or_null()==NULL case has to mean we are doing the error reporting very early in VM init - else how can we get in here in a "non attached" thread?

Thread::current_or_null()==NULL if we crash in a non attached thread or at/before VM init. The former case is typical if the VM is embedded into another launcher and foreign code crashes (not uncommon).

Arguably, in both cases the event log is not very interesting, but I'd still attempt to print it.

> Even then I'm not sure that is actually possible either - at what point in VM init have we installed our crash handler?

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PR: https://git.openjdk.java.net/jdk/pull/1408