Re: Kernel crash on device_map DEVICE_NULL

[Roland McGrath]

> Good point.  I will have to figure this out.  The port is not null, of
> course, but dev_port_lookup() is returning null because its kotype is
> IKOT_TASK and not IKOT_DEVICE: no doubt a bug in my code.

Indeed; after more examination I figured it must be a case like that.  
It's certainly in fact a bug in the kernel that it doesn't cope with that.
I've put the fix into both gnumach and oskit-mach.

> There sure are a lot of #ifdef i386 sections in dev_lookup.c and
> ds_routines.c, and they don't seem to have anything to do with the
> i386 architecture.  

As Marcus explained, this is just historical cruft.  For your project, I
think you would be better off starting with oskit-mach.  I have cleaned up
and removed a lot of random cruft there.  Also, the oskit module interfaces
are designed for exactly the kind of different-hosting concept that you are
working on.