Re: Now crashing [was Re: guile-2.9.2 and threading

[Mark H Weaver <mhw@netris.org>]

Hi Linas,

> Investigating the crash with good-old printf's in libguile/vm.c produces
> a vast ocean of prints ... that should have not been printed, and/or should
> have been actual errors, but somehow were not handled by scm_error.
> Using today's git pull of master, here's the diff containing a printf:
>
> --- a/libguile/vm.c
> +++ b/libguile/vm.c
> @@ -1514,12 +1514,23 @@ thread->guard); fflush(stdout); assert (0); }
>
>        proc = SCM_SMOB_DESCRIPTOR (proc).apply_trampoline;
>        SCM_FRAME_LOCAL (vp->fp, 0) = proc;
>        return SCM_PROGRAM_CODE (proc);
>      }
>
> +printf("duuude wrong type to apply!\n"
> +"proc=%lx\n"
> +"ip=%p\n"
> +"sp=%p\n"
> +"fp=%p\n"
> +"sp_min=%p\n"
> +"stack_lim=%p\n",
> +SCM_FRAME_SLOT(vp->fp, 0)->as_u64,
> +vp->ip, vp->sp, vp->fp, vp->sp_min_since_gc, vp->stack_limit);
> +fflush(stdout);
> +
>    vp->ip = SCM_FRAME_VIRTUAL_RETURN_ADDRESS (vp->fp);
>
>    scm_error (scm_arg_type_key, NULL, "Wrong type to apply: ~S",
>               scm_list_1 (proc), scm_list_1 (proc));
>  }
>
> As you can see, shortly after my printf, there should have been an
> error report.

Not necessarily.  Note that what 'scm_error' actually does is to raise
an exception.  What happens next depends on what exception handlers are
installed at the time of the error.

> There is no error report... until 5-10 minutes later, when the error
> report itself causes a crash.  Before then, I get an endless
> high-speed spew of prints:

It looks like another error is happening within the exception handler.

       Mark

PS: It would be good to pick either 'guile-devel' or 'guile-user' for
    continuation of this thread.  I don't see a reason why it should be
    sent to both lists.