Re: [uml-devel] UML + skas

[BlaisorBlade <blaisorblade_spam@yahoo.it>]

Alle 19:33, martedì 30 dicembre 2003, jeremie le-hen ha scritto:
> Hi all,

> I have just subscribed to this list because I found a strange bug while
> compiling an UML within an SKAS'd host.  Here is the problem :
>
> (my host is a 2.4.23 kernel with the SKAS patch released on 2002/11/11)

> After preprocessing the process.c file, I found that
> `struct ptrace_faultinfo' and `struct ptrace_ldt' were first defined
> in file `/usr/include/asm/ptrace.h' and then in
> `arch/um/include/skas_ptrace.h'.
> Since `/usr/include/asm/' is a symlink
> in  `/usr/src/linux/` which in turn points to my kernel source,

Making /usr/include/asm a symlink into kernel sources is a very bad thing; if 
your distro did this it's not your fault, but recent distros don't do this 
from ages (neither RedHat nor Mandrake, at least, for what I saw).

>
> This is *exactly* the same content as `arch/um/include/skas_ptrace.h'.
> From what I googled, it seems to be a known bug.  But it think it would
> not be very difficult to make some #define protection around theses
> structures to prevent from changing the destination of `/usr/src/linux/'
> to a source without the SKAS patch applied.

Yes, it wouldn't not hard.
But you should not use the same source tree to apply both patches. I think 
this is explained very clearly and that the patches are not meant to be 
compatible. Also, in that way you easily get into problems because 
include/asm points to asm-i386 and is not updated to point to asm-um.

Also, if you make /usr/include/asm (this holds also for /usr/include/linux) a 
symlink into kernel sources, that is not good.

And I don't think that any update to the host patch will ever be made 
available, since Jeff Dike is making ready the SKAS 4 patch.

-- 
cat <<EOSIGN
Paolo Giarrusso, aka Blaisorblade
Linux Kernel 2.4.21/2.6.0-test on an i686; Linux registered user n. 292729
EOSIGN



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