User-mode Linux kernel port

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>>>>> "Me" == Me  <lugzug@...> writes:
    Me> If I compile the uml kernel without hostfs is it possible for the
    Me> root user inside the uml machine to compile a hostfs kernel module
    Me> and insmod it?

  Yes.
  Chroot your UMLs before you invoke them.

  The chroot/setuid conflict really annoys me. We need a new kernel
call that will change the uid and the root at the same time.

]       ON HUMILITY: to err is human. To moo, bovine.           |  firewalls  [
]   Michael Richardson, Sandelman Software Works, Ottawa, ON    |net architect[
] mcr@... http://www.sandelman.ottawa.on.ca/ |device driver[
] panic("Just another Debian GNU/Linux using, kernel hacking, security guy"); [
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oh, do not include LKMs in your UML.

]       ON HUMILITY: to err is human. To moo, bovine.           |  firewalls  [
]   Michael Richardson, Sandelman Software Works, Ottawa, ON    |net architect[
] mcr@... http://www.sandelman.ottawa.on.ca/ |device driver[
] panic("Just another Debian GNU/Linux using, kernel hacking, security guy"); [

I'm using:

uml-patch-2.4.19-1
RH kernel source 2.4.18-10 (newest kernel for RHL7.3)

I need the RH kernel for RH addons like 'sar'.

The patch applied with only a couple offsets.

I did the, "make menuconfig ARCH=um" and turned off hostfs.

A "make linux ARCH=um" results in the below. Is there any way to
reconcile this?

[root@...]# make linux ARCH=um
[snip]
make -r -f tmp_include_depends all
make[1]: Entering directory `/usr/src/linux-2.4.18-10uml'
make[1]: Nothing to be done for `all'.
make[1]: Leaving directory `/usr/src/linux-2.4.18-10uml'
cc  -D__KERNEL__ -I/usr/src/linux-2.4.18-10uml/include -Wall
-Wstrict-prototypes -Wno-trigraphs -O2  -fno-strict-aliasing -fno-common
-Wno-unused -g  -U__i386__ -Ui386 -DUM_FASTCALL -D__arch_um__
-DSUBARCH=\"i386\" -D_LARGEFILE64_SOURCE
-I/usr/src/linux-2.4.18-10uml/arch/um/include -Derrno=kernel_errno
-DKBUILD_BASENAME=main -c -o init/main.o init/main.c
In file included from /usr/src/linux-2.4.18-10uml/include/asm/rwsem.h:8,
                 from
/usr/src/linux-2.4.18-10uml/include/linux/rwsem.h:29,
                 from
/usr/src/linux-2.4.18-10uml/include/asm/arch/semaphore.h:42,
                 from
/usr/src/linux-2.4.18-10uml/include/asm/semaphore.h:4,
                 from /usr/src/linux-2.4.18-10uml/include/linux/fs.h:200,
                 from
/usr/src/linux-2.4.18-10uml/include/linux/capability.h:17,
                 from
/usr/src/linux-2.4.18-10uml/include/linux/binfmts.h:5,
                 from /usr/src/linux-2.4.18-10uml/include/linux/sched.h:9,
                 from /usr/src/linux-2.4.18-10uml/include/linux/mm.h:4,
                 from /usr/src/linux-2.4.18-10uml/include/linux/slab.h:14,
                 from
/usr/src/linux-2.4.18-10uml/include/linux/proc_fs.h:5,
                 from init/main.c:15:
/usr/src/linux-2.4.18-10uml/include/asm/arch/rwsem.h: In function
`__down_write_trylock':
/usr/src/linux-2.4.18-10uml/include/asm/arch/rwsem.h:176: warning:
implicit declaration of function `cmpxchg'
In file included from
/usr/src/linux-2.4.18-10uml/include/linux/unistd.h:9,
                 from init/main.c:17:
/usr/src/linux-2.4.18-10uml/include/asm/unistd.h: At top level:
/usr/src/linux-2.4.18-10uml/include/asm/unistd.h:25: conflicting types for
`sys_read'
/usr/src/linux-2.4.18-10uml/include/linux/fs.h:659: previous declaration
of `sys_read'
/usr/src/linux-2.4.18-10uml/include/asm/unistd.h:26: conflicting types for
`sys_write'
/usr/src/linux-2.4.18-10uml/include/linux/fs.h:660: previous declaration
of `sys_write'
make: *** [init/main.o] Error 1
[root@...]#

Are there any compile time hacks that can make UML 'go faster' on an
Athlon?

Lugzug

Me wrote:
> uml-patch-2.4.19-1
> RH kernel source 2.4.18-10 (newest kernel for RHL7.3)

So, you're applying a 2.4.19 patch to a RedHat-patched-2.4.18, and 
you're wondering why it's not working? Try downloading a clean 2.4.19 
tarball from ftp.kernel.org, patch that with uml-patch-2.4.19-1, and see 
what happens.

> I need the RH kernel for RH addons like 'sar'.

Lots of people run UMLs with RH images without any RedHat specific 
patches. I did for a while. Remember, you don't have to run the same 
distribution on the host and the UML.

David

-- 
David Coulson                                  http://davidcoulson.net/
d@...                       http://journal.davidcoulson.net/

On Fri, 30 Aug 2002, David Coulson wrote:

> Me wrote:
> > uml-patch-2.4.19-1
> > RH kernel source 2.4.18-10 (newest kernel for RHL7.3)
>
> So, you're applying a 2.4.19 patch to a RedHat-patched-2.4.18, and
> you're wondering why it's not working? Try downloading a clean 2.4.19
> tarball from ftp.kernel.org, patch that with uml-patch-2.4.19-1, and see
> what happens.

I didn't 'wonder why it's not working'.  I asked if the
problem can be reconciled.

I BTW, try a clean 2.4.19. The multi-disk module and the apple talk module
failed to build properly. I don't know if that is a vanilla 2.4.19 problem
or a 2.4.19+uml patch problem.

> > I need the RH kernel for RH addons like 'sar'.
>
> Lots of people run UMLs with RH images without any RedHat specific
> patches. I did for a while. Remember, you don't have to run the same
> distribution on the host and the UML.

Everything you say is true, yet again, I need 'RH addons like sar'.

Lugzug

Me wrote:
> I BTW, try a clean 2.4.19. The multi-disk module and the apple talk module
> failed to build properly. I don't know if that is a vanilla 2.4.19 problem
> or a 2.4.19+uml patch problem.

Can you not disable either/both of those?

> Everything you say is true, yet again, I need 'RH addons like sar'.

Fair enough. I've not used RH in yonks, so I can't help you too much 
there - What is 'sar' anyway?

David

-- 
David Coulson                                  http://davidcoulson.net/
d@...                       http://journal.davidcoulson.net/

On Thu, Aug 29, 2002 at 06:43:32PM -0700, Me wrote:

> Everything you say is true, yet again, I need 'RH addons like sar'.

What is so special about this sar that it requires a patched kernel?  sar
from sysstat works just fine for me with stock kernels.

-- 
 - mdz

On Thu, Aug 29, 2002 at 06:43:32PM -0700, Me wrote:
> Everything you say is true, yet again, I need 'RH addons like sar'.

So why not just grab kernel-uml-2.4.18-11.i686.rpm from the current
Red Hat beta (null)?

Here's a copy on my mirror:

http://ftp.silug.org/pub/redhat/linux/beta/null/en/os/i386/RedHat/RPMS/kernel-uml-2.4.18-11.i686.rpm

I haven't tried it personally, but if you really need a Red Hat
kernel, it is worth a try.  (And if it doesn't work for you, you
probably want to submit a bug report to bugzilla.redhat.com before the
next beta or release.)

Oh, and there also seems to be a kernel-uml-2.4.18-12.5.i686.rpm in
Rawhide at the moment.

Steve
-- 
steve@...           | Southern Illinois Linux Users Group
(618)398-7360             | See web site for meeting details.
Steven Pritchard          | http://www.silug.org/