user-mode-linux-user

[uml-user] Usage of UML (User Mode Linux)

[Lei Y. <ly...@ec...>]

Dear fellows,

I am new to kernel modules and am trying to get a module work right now. I 
need some tools to debug. In order not to risk the host machine, I am 
thinking of using UML. I downloaded the kernel RPM

------user_mode_linux-2.4.19.5um-0.i386.rpm

and root filesystem

------Debian-3.0r0.ext2.bz2

and got Debian boot sucessfully. However, I still have several questions:

1. The kernel version does not match filesystem:
(none):/lib/modules# ls
2.4.18-37um
(none):/lib/modules# uname -r
2.4.19-5um

2. How do I get my own module compiled into the kernel and debug with it?

I've been reading the UML homepage 
http://user-mode-linux.sourceforge.net/index.html 

but have not really found tips helpful to me. Could anyone give me any hint 
how to do this, or where to look at?

TIA!

Lei

Re: [uml-user] Usage of UML (User Mode Linux)

[Ralph <ra...@de...>]

Am Freitag 17 September 2004 18:58 schrieb Lei Yang:
> Dear fellows,
>
> I am new to kernel modules and am trying to get a module work right now. I
> need some tools to debug. In order not to risk the host machine, I am
> thinking of using UML. I downloaded the kernel RPM
>
> ------user_mode_linux-2.4.19.5um-0.i386.rpm
>
> and root filesystem
>
> ------Debian-3.0r0.ext2.bz2
>
> and got Debian boot sucessfully. However, I still have several questions:
>
> 1. The kernel version does not match filesystem:
> (none):/lib/modules# ls
> 2.4.18-37um
> (none):/lib/modules# uname -r
> 2.4.19-5um

You have to copy /usr/lib/uml/modules/... (from the host) to /lib/modules (on 
the guest) to have the correct modules for the installed uml kernel.

> 2. How do I get my own module compiled into the kernel and debug with it?

apt-get install kernel-source-2.4.19
apt-get source user-mode-linux
cd user-mode-linux
debian/rules unpack
debian/rules patch
debian/rules configure
cd kernel-source-2.4.19
make menuconfig
<edit the config>
cp .config ../config
cd..
dpkg-buildpackage -b

this will built your own user-mode-linux debian package with the config of 
your choice.

I hope the commands are 100% correct, but I am not sure, because I never used 
the quite old woody version myself.

> I've been reading the UML homepage
> http://user-mode-linux.sourceforge.net/index.html
>
> but have not really found tips helpful to me. Could anyone give me any hint
> how to do this, or where to look at?
>
> TIA!
>
> Lei

--Ralph

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Re: [uml-user] Usage of UML (User Mode Linux)

[BlaisorBlade <bla...@ya...>]

On Friday 17 September 2004 19:29, Ralph Pa=DFgang wrote:
> Am Freitag 17 September 2004 18:58 schrieb Lei Yang:
> > Dear fellows,
> >
> > I am new to kernel modules and am trying to get a module work right now.
> > I need some tools to debug. In order not to risk the host machine, I am
> > thinking of using UML. I downloaded the kernel RPM
> >
> > ------user_mode_linux-2.4.19.5um-0.i386.rpm
> >
> > and root filesystem
> >
> > ------Debian-3.0r0.ext2.bz2
> >
> > and got Debian boot sucessfully. However, I still have several question=
s:
> >
> > 1. The kernel version does not match filesystem:
> > (none):/lib/modules# ls
> > 2.4.18-37um
> > (none):/lib/modules# uname -r
> > 2.4.19-5um
>
> You have to copy /usr/lib/uml/modules/... (from the host) to /lib/modules
> (on the guest) to have the correct modules for the installed uml kernel.
>
> > 2. How do I get my own module compiled into the kernel and debug with i=
t?

Well, first you must compile the UML on your own. The version from the UML=
=20
package can be called "totally screwed up". If you add your module inside t=
he=20
tree (you must know kbuild) then you are on the right route.

You can find info about how to do this on=20
http://user-mode-linux.sourceforge.net/compile.html

At the end of the "Compiling and installing kernel modules" section, it als=
o=20
explains how to fix external modules makefiles.

>
> apt-get install kernel-source-2.4.19
> apt-get source user-mode-linux
> cd user-mode-linux
> debian/rules unpack
> debian/rules patch
> debian/rules configure
> cd kernel-source-2.4.19
> make menuconfig
> <edit the config>
> cp .config ../config
> cd..
> dpkg-buildpackage -b

> this will built your own user-mode-linux debian package with the config of
> your choice.
> I hope the commands are 100% correct, but I am not sure, because I never=
=20
used=20
> the quite old woody version myself.

Well, maybe he does not use Debian for his host, and anyway, using a so old=
=20
UML version is just hunting for bugs. The stabler 2.4 release is 2.4.24-1;

 the 2nd most stable is 2.4.26-3, if you don't care about hostfs working.

Bye
=2D-=20
Paolo Giarrusso, aka Blaisorblade
Linux registered user n. 292729