[Haskell-cafe] Possible bug in Criterion or Statistics package

[Aleksey Khudyakov]

On 13.08.2012 20:26, Till Berger wrote:
>> Terrible! Quite sorry that this seems to be a bug in the monad-par
>> library.
>>
>> I'm copying some of the other monad-par authors and we hopefully can
>> get to
>> the bottom of this. If it's not possible to create a smaller reproducer,
>> is it possible to share the original test that triggers this problem? In
>> the meantime, it's good that you can at least run without parallelism.
>
> I have attached an even simpler test that directly uses the monad-par
> library. The function "test" simply adds one to a list of numbers
> indefinitely using "parMap" and displays every intermediate result. When
> running the program on multiple cores the bug occurs every time for me.
>
> Thanks for looking into this!
>
I've tried your test case and it indeed fails every time. Usually it 
fails with "blocked on MVar indefinitely" but sometimes it fails with:


[2]
[3]
test: Impossible state in globalWorkComplete.