Quoth diego souza, ...
The following one is quite interesting, though. The moment I insert the threadDelay function (like in the previous example), it fails some times (it seems to have something to do with cpu idleness). I guess this this explains why the previous version didn't work properly for me:
For me, this example kind is of ambiguous. I thought it seemed clear enough from your earlier results, that executeFile played some role in the problem, but in this example the two locking forks are parallel, and it's entirely possible that both lock syscalls will complete before either executeFile has finished or even begun, so ... unless I'm missing something (again!) I guess I would say this calls for a lot more tests to verify that you have this problem only with executeFile, and not with, say, a Haskell fork that does the same thing (sleep and exit.) By the way, I haven't been able to duplicate the problem with 6.12.3 on MacOS. Donn