Axel Krauth <krauth@infosun.fmi.uni-passau.de> wrote,

at the moment I'm writing a haskell/C programm using the FFI. But I'm getting always a segfault in the haskell part (according to gdb) .

With Linux the segfault happens at random (while I'm doing a lot of calls to haskell via a dynamically exported function). With Unix gdb says it occurs in 'StgReturn' called from 'stg_returnToStackTop' after the C part finishes it job.

I already put a C frontend instead of the haskell part and searched for access violations and other memory missmanagement in the C part (none). I also disabled (with no effect) all finalizers of the ForeignObj's used.

As I'm relatively new to Haskell I don't know how to hunt that one down. Unfortunately the programm is already huge (ca. 4000 LOC Haskell & C) so the buggy part of the programm is not obvious (for me).

Could someone give me a hint/technique how to approach the problem?

As SimonM already said, there is *unfortunately* not much in the way of real support for hunting down such bugs. Did you try linking with Electric Fence (see `man efence' on your Linux box)? This may force the bug to occur earlier, which might make it easier to track down. Are you using the `Concurrent' module? Cheers, Manuel