[Pkg-uml-pkgs] Bug#399328: linux-patch-skas: user-mode-linux seems to not work on 2.6.18 patched with this package

[Peder Chr. Nørgaard]

On Friday 24 November 2006 15:50, Peder Chr. Nørgaard wrote:

>
> 	I have a correction to the original report; well, the report is correct,
> but I had made a mistake, which I corrected with no effect to the problem. 
> I am not running this on a -686 CPU, but on an AMD Athlon, so I should
> really use -k7 kernels all the way through.  So I switched to a mainstream
> -k7 kernel and a home-built -k7 kernel with SKAS; no changes, works fine on
> mainstream kernel, but the bug is still when SKAS patch is added to host
> system.  So the problem *may* theoretically be local to the fact that I am
> using an AMD Athlon CPU; I just don't think that is very likely.  If I can,
> I will try it out on a Pentium-based computer.
>

Hello.
	I have now got my hands on a Pentium-based computer, and, to my big surprise, 
the problem is *not* manifest on the Pentium-based PC.  Let me recapture:  
the problem is, that linux 2.6.18 kernel patched with the skas patch 
distributed by Debian package linux-patch-skas (which is really just the skas 
patch from blaisorblade's workshop) does not work with the (x86-variant 
agnostic) user-mode-linux distributed by Debian.  The user-mode-linux hangs 
consistently somewhere in the boot process, described in a little more 
detalins in my original report.

	But I have only observed the problem on my AMD Athlon XP 2200+;  today, when 
I try to do the same thing on an Intel Pentium (it is a Pentium M) it works 
just fine.

	Whether it works on the AMD or not has nothing to do with whether I build the 
host kernel as -686 or -k7 - the problem is manifest in both cases.  So it is 
related to the chip rather than to the compilation, I think.

	So it seems that the problem is local to both 2.6.18 *and* the AMD Athlon 
CPU; I realize that this does not exactly makes it easier to figure out what 
happens.

	Please, if I can be of any assistance, tell me how.  The problem is easy to 
reproduce, and even though I don't know much about the internals of 
user-mode-linux - I am just a happy user of user-mode-linux for testing and 
similar purposes - I do now a little about how to drive a gdb around in a 
guest kernel.  If someone would tell me what to look for, I might be able to 
figure out at least where in the boot sequence the guest is hanging

best regards
-- 
Peder Chr. Nørgaard     e-mail: pcn at pogt.dk
Gefionsvej 19           spejder-e-mail: hathi at gallerne.dk
DK-8230 Åbyhøj          tel: +45 87 44 11 99
Denmark                 mob: +45 30 91 84 31