Re: CVS commit: src/sys/arch/i386/i386

[Matthias Drochner <M.Drochner%fz-juelich.de@localhost>]

david%l8s.co.uk@localhost said:
> I presume the panic was in the 'return to user' sequence?

Yes, in the iret.

> Does it now SIGSEGV the program?

Yes, which is a bit strange because this happened before
even the first instruction was fetched, and no user-supplied
data are involved (as opposed to setmcontext).
It was entirely the kernel's fault, so a panic would be
only fair.

> (putting in the kernel %cs might leave you running user code with
> kernel privelege)

This couldn't happen here because the CPL=3 is set together with
the CS descriptor, so one should get a GPF on any attempt to
use a kernel descriptor.

best regards
Matthias



------------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------------
Forschungszentrum Juelich GmbH
52425 Juelich
Sitz der Gesellschaft: Juelich
Eingetragen im Handelsregister des Amtsgerichts Dueren Nr. HR B 3498
Vorsitzende des Aufsichtsrats: MinDir'in Baerbel Brumme-Bothe
Geschaeftsfuehrung: Prof. Dr. Achim Bachem (Vorsitzender),
Dr. Ulrich Krafft (stellv. Vorsitzender), Prof. Dr.-Ing. Harald Bolt,
Prof. Dr. Sebastian M. Schmidt
------------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------------