[Haskell-cafe] GHC threaded RTS will call the finaliser of a ForeignPtr while references still exist

[Adam Langley]

I believe that I've managed to distill a crash which has been driving
me crazy for a few days into a short enough test case (22 lines) that
it might be useful.

In short: the threaded RTS will call the finialiser of a ForeignPtr
while an exception handler still holds a reference to it:


% ghc -make fptest.hs cbits.c -threaded
[1 of 1] Compiling Main             ( fptest.hs, fptest.o )
Linking fptest ...
% ./fptest
New object getting created: 66f010
Finaliser getting called for 66f010
Use called for 66f010


cbits.c: http://hpaste.org/6420
fptest.hs: http://hpaste.org/6421

I'm hoping that this is useful to someone who knows the RTS.

Cheers,


-- 
Adam Langley agl at imperialviolet.org http://www.imperialviolet.org