Weird bug on Mac OS X

[Dominick LoBraico]

Confirmed segfault on 10.8.2 with latest core (108.07.01) and OCaml 
4.00.1+short-types.

On Thursday, November 8, 2012 11:47:21 AM UTC-6, Anil Madhavapeddy wrote:
>
> Looks like another misaligned stack pointer somewhere; two were fixed 
> already here: 
> http://caml.inria.fr/mantis/view.php?id=5700 
>
> MacOS 10.8 strictly needs a 16-byte aligned stack or else lots of systems 
> functions decide to throw in the towel (due to them using SSE instructions 
> by default now). 
>
> #0  0x00007fff8e4ad8a5 in misaligned_stack_error_entering_dyld_stub_binder 
> () 
> #1  0x0000000000000103 in ?? () 
> #2  0x0000000100254068 in caml_absf_mask () 
> #3  0x000000010022e923 in caml_raise () 
> #4  0x000000010022ec71 in caml_array_bound_error () 
> #5  0x000000010000b32a in .L101 () 
>
>
> -a 
>
> On 8 Nov 2012, at 17:16, Markus Mottl <markus... at gmail.com <javascript:>> 
> wrote: 
>
> > Should have mentioned that, too: I'm running Mac OS X 10.8.2 with the 
> > latest XCode version (4.5.2). 
> > 
> > On Thu, Nov 8, 2012 at 12:11 PM, Ashish Agarwal <agarw... at gmail.com<javascript:>> 
> wrote: 
> >> I correctly get an exception with OCaml 3.12.1, Core 108.00.02, on Mac 
> OS X 
> >> 10.7.5. 
> >> 
> >> On Thu, Nov 8, 2012 at 12:04 PM, Markus Mottl <markus... at gmail.com<javascript:>> 
>
> >> wrote: 
> >>> 
> >>> Hi, 
> >>> 
> >>> I've run into a segfault on Mac OS X with a very trivial program that 
> >>> basically just links with Jane Street Core.  Here is the file test.ml: 
>
> >>> 
> >>> ---------- 
> >>> module X = Core 
> >>> 
> >>> let () = [||].(0) <- 42 
> >>> ---------- 
> >>> 
> >>> You can build it as follows: 
> >>> 
> >>>  ocamlbuild -use-ocamlfind -cflag -thread -lflag -thread -pkgs core 
> >>> test.native 
> >>> 
> >>> Running test.native will give you a segfault.  Here is the stack 
> >>> backtrace: 
> >>> 
> >>> ---------- 
> >>> #0  0x00007fff90fa78a5 in 
> misaligned_stack_error_entering_dyld_stub_binder 
> >>> () 
> >>> #1  0x0000000000000103 in ?? () 
> >>> #2  0x0000000101c0a088 in pvars () 
> >>> #3  0x0000000101bddedd in caml_raise () 
> >>> #4  0x0000000101bddf99 in caml_array_bound_error () 
> >>> #5  0x00000001019b6aca in .L101 () 
> >>> ---------- 
> >>> 
> >>> The program should just raise an exception due to the illegal array 
> >>> access.  Merely raising an exception directly doesn't trigger the 
> >>> problem.  The program won't segfault either if the "module X = Core" 
> >>> line is commented out, i.e. Core has to be linked in.  Other libraries 
> >>> apparently also don't cause this issue. 
> >>> 
> >>> Could another Mac OS X user here please verify the problem?  I'm using 
> >>> OCaml 4.00.1 with Opam and the latest release of Core in there. 
> >>> 
> >>> Maybe somebody more knowledgeable about stack alignment and linking 
> >>> issues on Mac OS X has an idea what's going wrong here.  I suspect 
> >>> it's a code generation, linking or even runtime issue that may need to 
> >>> be fixed in the compiler.  Or there could be a bug in some module 
> >>> initialization in Core that is using C-bindings (less likely, I'm not 
> >>> aware of anything that could cause this). 
> >>> 
> >>> Regards, 
> >>> Markus 
> >>> 
> >>> -- 
> >>> Markus Mottl        http://www.ocaml.info        markus... at gmail.com<javascript:> 
> >> 
> >> 
> > 
> > 
> > 
> > -- 
> > Markus Mottl        http://www.ocaml.info        markus... at gmail.com<javascript:> 
> > 
>
>
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