How to debug a segfault.

[Simon Marlow]

David Brown wrote:
> I'm developing a program with GHC-6.6.  I've been on amd64, and
> haven't had problems, but now when I run the program on on x86 (after
> cleaning and recompiling), I'm getting a segfault.
> 
> gdb isn't very helpful at all:
>     Program received signal SIGSEGV, Segmentation fault.
>     [Switching to Thread -1212873040 (LWP 26946)]
>     0x080b45b8 in s2EI_info ()
>     (gdb) bt
>     #0  0x080b45b8 in s2EI_info ()
>     #1  0x081757a8 in ?? ()
>     #2  0x00000004 in ?? ()
>     #3  0xb7875278 in ?? ()
> 
> I am using some various bindings to some C libraries, some I have
> written and some written by others.  But, I'm not able to figure out
> where to even begin looking for the problem.
> 
> Any advice on how I might be able to better debug this?  Would
> compiling unregistered help (I'll have to figure out how to build
> libraries for that)?

Fortunately I wrote a wiki page on just this subject, mainly so that I can say 
RTFM :-)  After reading the FM, if you're still having difficulties then post a 
followup and we'll try to help if we can.

   http://hackage.haskell.org/trac/ghc/wiki/DebuggingGhcCrashes

Cheers,
	Simon