Hotspot crash compiling sun.invoke.util.ValueConversions::identity

[Vladimir Ivanov]

Eirik,

Thanks for the report!

As a first step, I'd like to see corresponding hotspot crash log 
(hs_err_pid*.log).

It seems you stepped on a bug in invokedynamic implementation (lambdas 
are translated into indy calls on bytecode level) which happens when it 
is initialized too early in VM lifecycle (e.g. java agent premain).

I'd be grateful for a stand-alone test case (focus on premain method 
logic) or steps how to reproduce it myself.

Best regards,
Vladimir Ivanov

On 3/2/15 4:10 AM, Eirik Bjørsnøs wrote:
> Ladies and gentlemen,
>
> Last week, some of the world's brightest, most capable and all round
> good looking Java developers gathered in Crested Butte, Colorado for
> the Winter Tech Forum (WTF) 2015 [1].
>
> Wednesday was Hackathon Day, and a group of us decided to embark the
> adventure of creating a live Java code coverage engine called Skybar
> [2].
>
> We made good progress and by the afternoon we knew we'd have something
> good to show at the 8pm showcase. So we confidently headed over to
> Ryce Asian Bistro [3] at 17:30 for a nice team dinner.
>
> Luckily we went easy on the saké, because when we came back to
> finalise our demo, we found that Hotspot had crashed:
>
> # A fatal error has been detected by the Java Runtime Environment:
> #
> #  SIGBUS (0xa) at pc=0x000000012a6d61e6, pid=10738, tid=18691
> [..]
> Compiled method (c2)  152453 1542       4
> sun.invoke.util.ValueConversions::identity (2 bytes)
>
> Shock, horror! Our demo was just minutes away, would we be able to
> present? Our team immediately went into debugging mode:
>
> Could we reproduce without using our -javaagent? No. Was the crash
> consistently reproducible? Kind of, but we had to stress test our
> code. Was there a any consistency in the hs_err reports? Yes, it
> seemed to always involve lambda expressions in out agent code.
>
> The team decided we had to remove all lambdas from our agent code in
> the hope that would improve the situation. And it did! At 7:50 PM, we
> had a stable build and ran out to make it to the presentations.
>
> Skybar was very well received. Our demo worked. Nothing crashed.
> Applause and shouts of "Ship it!" was heard from the audience. It was
> good times. We headed over to the Princess Wine Bar [4] for some
> celebratory drinks.
>
> The team is continuing our work on Skybar. But we miss our lamdas, and
> we want them back! To achieve this, we need help from the Hotspot
> team. On our side, we are willing to  work with you try to make
> reproducible test cases and collect any other useful information.
>
> What would be the best next step in saving Lambas on Agents? We would
> love to help out fixing this. Should we file an issue somewhere and
> upload our hs_err file(s)?
>
> On behalf of the Skybar team -
> Eirik,
>
> [1] http://www.mindviewinc.com/Conferences/JavaPosseRoundup/
> [2] https://github.com/WinterTechForum/skybar
> [3] http://www.ryceasianbistro.com
> [4] https://www.facebook.com/princesswinebar
>