How to test lock mode compatibility?

[Aleksey Shipilev]

On 08/31/2018 08:12 PM, Adam Retter wrote:
> Hmm, before I understand how to test with #lock(), it seems I am still
> far from understanding JCStress or the JMM correctly. I just realised
> that my ReentrantReadWriteLockBooleanCompatibilityTest actually fails
> on JCStress.
> 
> The following test fails:
> 
> @JCStressTest
> @Outcome(id = "true, false", expect = Expect.ACCEPTABLE, desc = "T1
> acquired X, and T2 could not acquire X")
> @Outcome(id = "false, true", expect = Expect.ACCEPTABLE, desc = "T2
> acquired X and T1 could not acquire X")
> public static class X_X {
>     @Actor
>     public void actor1(S s, ZZ_Result r) { r.r1 = s.exclusive(); }
>     @Actor
>     public void actor2(S s, ZZ_Result r) { r.r2 = s.exclusive(); }
> }
> 
> It reports, Observed forbidden state: true, true.

This looks like a bug -- actors are executed by the same thread, probably during initial sanity
checks, hm.

-Aleksey