Re: [Xen-devel] caml stubdom crashes

[Alex Zeffertt <alex.zeffertt@xxxxxxxxxxxxx>]

George S. Coker, II wrote:
> On 4/2/09 12:22 PM, "Patrick Colp" <pjcolp@xxxxxxxxx> wrote:
>
> > Alex Zeffertt wrote:
> > > Hello ocaml minios stubdomain experts (that's narrowed down the list
> > > somewhat!)
> > >
> > > I've been playing with the caml version of the "hello world" example
> > > stubdomain that can be found in xen-unstable.hg/stubdom/caml/.
> > >
> > > If I make the following trivial modification to stubdom/caml/hello.ml
> > > the stub domain page faults.  According to addr2line the page fault is
> > > in ungetc.c:0.
> > >
> > > --- a/stubdom/caml/hello.ml    Mon Mar 30 11:42:16 2009 +0100
> > > +++ b/stubdom/caml/hello.ml    Thu Apr 02 15:15:45 2009 +0100
> > > @@ -1,4 +1,6 @@
> > > +let yr = 2009
> > > +
> > >  let main arg =
> > > -  Printf.printf "Hello, world!\n%!."
> > > +  Printf.printf "Hello, world %d!\n%!." yr
> > >
> > >  let _ = Callback.register "main" main
> > >
> > >
> > > Without the above change the stub domain runs as expected, i.e. it does
> > > not page fault.
> > >
> > > I suspect the problem is that the caml-stubdom target in
> > > stubdom/caml/Makefile compiles stubdom/caml/hello.ml and links it with
> > > $(CAMLLIB)/libasmrun.a.  But this is a library compiled for the
> > > development machine platform (linux-i386-glibc) not for the stubdomain
> > > platform (minios-i386-newlib).
> I don't think this is a linux-i386-glibc vs minios-i386-newlib issue but
> rather the FORTIFY compiler options that introduce the
> __fprintf_chk/__sprintf_chk funcs.  There is still something about the
> behavior of the FORTIFY options that I am still not accounting for.  As
> Patrick points out, special ports of ocaml should not be (and have not been)
> necessary.
>  
Hi George, thanks for replying.

Is this an option that was used when the ubuntu package managers built ocaml, 
but was not used by Debian.  Or have I misunderstood.
I'm using your "_chk and _fail canaries" patch (actually I've had to extend it 
as I got even more undefined syms when I tried to compile 
xen-ocaml-tools/xenstored.)  Are you saying that there is a problem with this patch?
Regards,

Alex

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