A Virtual Home - Latest Comments in How to compile a kernel for Ubuntu Karmic

Re: How to compile a kernel for Ubuntu Karmic

Andrew — Thu, 29 Mar 2012 20:28:26 -0000

Wow...I am just learning these words in my IT classes. Recognize I have a lot to learn and actually study and understand.

Re: How to compile a kernel for Ubuntu Karmic

Jon Leighton — Thu, 07 Oct 2010 02:45:03 -0000

Hi Peter -

I'm trying to rebuild 2.6.31-22.65 generic-pae. I'm not modifying the configuration but I'm applying a patch to net/sctp/transport.c. After building the kernel, I get the 3 linux-*_all.deb files, but not the linux-header*.deb and linux-soruce*.deb files that correspond to the configuration I created. I've been through the process twice with the same result. Do you have any suggestions for what might be going wrong? Thanks.

- Jon

Re: How to compile a kernel for Ubuntu Karmic

Pav — Fri, 24 Sep 2010 12:41:10 -0000

Hello Peter.
Thank you for the reply.
I am not using git - all my changes are going to be local.

Unfortunately, even to see if there are any syntax errors in my new changes, I need to recompile to whole kernel and that s what is bothering me.

A simple makefile is capable of detecting source code changes - thats what it is meant for. Not sure why ubuntu made it so complicated - there is so much that goes under the hood but leaves out this simple and most important requirement!

Sorry to rant here, but I have already done 3 full compiles of the kernel since yesterday - I am new to kernel development, I cant generate the perfect code without going through few iterations!

Thanks a lot for trying to help.

Re: How to compile a kernel for Ubuntu Karmic

Peter — Fri, 24 Sep 2010 12:09:26 -0000

Not sure why it wouldn't show up at boot time, unless you also have grub v2 installed and it's not added in that configuration.

Re: How to compile a kernel for Ubuntu Karmic

Peter — Fri, 24 Sep 2010 12:07:46 -0000

If you add files or make changes you will have to commit them to the Git tree, otherwise they will be undone when you do a git reset.

I haven't found documents about incremental compiling a kernel, it might be possible but I wouldn't know about it.

For help I would start at http://kernel.org they have mail listings available where you can posts questions like adding your own file.

Re: How to compile a kernel for Ubuntu Karmic

Pav — Fri, 24 Sep 2010 07:21:20 -0000

I followed the above procedure to compile a new kernel based out of Karmic and I could even install and run it. Thanks a lot.
I have added my own stuff to the kernel code and there are some errors in it (doesn't interfere with the kernel's regular functionality - error happens only when I create a particular kind of socket).

Now to fix this error, I have made changes in udp.c, xfrm.h etc. And then issued the last command from your tutorial above
"skipabi=true skipmodule=true fakeroot debian/rules binary-kvp"
I hoped that this would recompile the changed files - but it never does. I verified this by removing the corresponding .o files from debian/build/build-kvp/ path and they did get created on running the above command after my changes.

How do i do incremental compiles of the kernel src tree (after I have done the complete build once) without having to do complete clean and compile - this takes nearly 3hrs to run on my VirtualBox :(

Also, if i want to add a new file to the kernel source tree at say net/ipv4/myownfile.c - can I get it compiled by just adding it in the net/ipv4/Makefile under a specific config item that I know I would be selecting?

Can you point me to help-pages on these tips-tricks on kernel-developer's everyday life? Thanks a lot.

Regards
Pav

Re: How to compile a kernel for Ubuntu Karmic

subhash pujari — Fri, 17 Sep 2010 15:15:12 -0000

Hi Peter,

I am new to linux enviornment. Thanks for the tutorial, I have followed all the step mentioned in the site and installed the new image of the linux kernel. Its showing in the grub.conf, but the new system its not showing in the boot time.

Re: How to compile a kernel for Ubuntu Karmic

Peter — Sat, 01 May 2010 11:55:18 -0000

Take a look at this one:
http://blog.avirtualhome.co...

I don't think it has changed for compiling a Lucid kernel on Lucid but I haven't had the chance to upgrade yet, projects have been keeping me busy.

Re: How to compile a kernel for Ubuntu Karmic

Thai Dang Vu — Sat, 01 May 2010 11:04:05 -0000

Now Lucid was out there. Is anybody willing to write something like this for 10.04?

Let me start with this:

- debian.master/scripts/misc/kernelconfig doesn't exist, but debian/scripts/misc/kernelconfig does

- in kernelconfig, there's this line: bindir="`pwd`/${DROOT}/scripts/misc" I had to change it to bindir="`pwd`/${DROOT}/debian/scripts/misc"

- debian.master/scripts/misc/getabis doesn't exist, but debian/scripts/misc/getabis does and it doesn't contain any line like this getall i386 generic generic-pae 386. So I cannot make any change to that file.

- I had to install these packages: binutils-dev, libelf-dev, asciidoc (wow, Need to get 359MB of archives.
After this operation, 562MB of additional disk space will be used.)

And finally, I got
linux-doc_2.6.32-22.33_all.deb
linux-headers-2.6.32-22_2.6.32-22.33_all.deb
linux-headers-2.6.32-22-core2_2.6.32-22.33_i386.deb
linux-image-2.6.32-22-core2_2.6.32-22.33_i386.deb
linux-source-2.6.32_2.6.32-22.33_all.deb
linux-tools-common_2.6.32-22.33_all.deb

Re: How to compile a kernel for Ubuntu Karmic

Wrightflyer — Fri, 30 Apr 2010 09:20:16 -0000

As I said "apt-get source linux-image-2.6.31-20-generic" so it should be EXACTLY the same source that builds the linux-image-2.6.31-20-generic.deb that is in the Karmic repository.

Re: How to compile a kernel for Ubuntu Karmic

Peter — Thu, 29 Apr 2010 16:34:51 -0000

Where are you getting your kernel source from?

Re: How to compile a kernel for Ubuntu Karmic

Wrightflyer — Thu, 29 Apr 2010 15:57:07 -0000

Regarding Wim's post number 15 above. I'm seeing what he saw, that is that the source initially only has debian.master/ but no debian/, your advice was to run "debian/rules clean" and it would be created. But how is that possible? You can't run "debian/rules" if there is no debian/ ?

I found that I could create debian/ using "make-kpkg debian" but that stil does not create the debian.env that debian/rules/misc/kernelconfig is looking for. If I use "debian/rules clean" while debian/ exists then it is actually deleted. So attempting to run that twice is NOT the solution (in fact it's simply not possible)

Any ideas?

Initially all I'm trying to do is build EXACTLY the same linux-image-2.6.31-20-generic that you get from Ubuntu repositories that you get with "apt-get source linux-image-2.6.31-20-generic". The problem is getting the .config right. It does not work to simply copy Config-NNN from /boot of a system that already has linux-image-2.6.31-20-generic installed because the Config-NNN file that is put there has CONFIG_DEBUG_INFO=y which the kernel itself clearly did not have when it was built.

Wrightfyer

Re: How to compile a kernel for Ubuntu Karmic

Peter — Tue, 13 Apr 2010 17:31:11 -0000

They should affect the build. These two are not redefined elsewhere in the scripts, they are exported in the Makefile for later use.

Re: How to compile a kernel for Ubuntu Karmic

Georgios Zarkadas — Fri, 09 Apr 2010 15:01:52 -0000

Hi Peter,

Great post! When I first read it I said to my self: "too easy to be true"; but I followed your instructions and it worked flawlessly! I am now righting from my new with Core2-optimized kernel system. Many thanks!

I have a question: wanting to get the most out of performance I did tweak a little the top-level Makefile at lines 224 and 225 making the following changes:

HOSTCFLAGS = -Wall -Wstrict-prototypes -O3 -mtune=native -march=native -fomit-frame-pointer
HOSTCXXFLAGS = -O3 -mtune=native -march=native

Did those options actually affected the build? I am asking this because there are other options below and I don't know well enough how the kernel build system actually works and whether it is the value of these flags that is propagated to directories below or of others. The compilation output does not help either (at least at the default verbosity level that I used).

Hope you can shed some light on this; and thanks again for this concise and highly useful post!

Re: How to compile a kernel for Ubuntu Karmic

Andy Whitcroft — Tue, 30 Mar 2010 13:01:04 -0000

It should be noted that you should not call kernelconfig directly to edit the configurations ... you should use:

debian/rules editconfigs

Re: How to compile a kernel for Ubuntu Karmic

Paul B — Wed, 24 Mar 2010 02:01:30 -0000

Great post. It would also be great detailing how to upload this into a launchpad PPA. Then it could be managed from there and taking advantage of their build daemons.

Re: How to compile a kernel for Ubuntu Karmic

cac gomboo — Sun, 21 Mar 2010 12:07:43 -0000

Yeah, no such thing in my menuconfig. :( However, I put it manually as CONFIG_HIGHMEM64G=y, but not even I've got more, it reduced from 3GB to 2.82G. (No memory related options in Bios)
Anyway, thanks! I gave it a try..

Re: How to compile a kernel for Ubuntu Karmic

Peter — Sat, 20 Mar 2010 16:56:41 -0000

Location: Processor type and features -> High Memory Support -> 64GB

Re: How to compile a kernel for Ubuntu Karmic

cac gomboo — Sat, 20 Mar 2010 16:29:14 -0000

Hey,
You said, you made the compilation because you need 4G support. Which option gave you this in menuconfig? I don't see you mentioned it at all.. :(

Re: How to compile a kernel for Ubuntu Karmic

goro4111 — Sun, 14 Feb 2010 10:43:11 -0000

Thanks for the detailed well structured HOWTO. It actually helped me a lot to start compiling the kernel form my old pc.

I must say that I followed all the step, several times, and I do not see any problem with the steps themselves, but I have a problem with booting up with the kernel I made.

After I compile my kernel (2.6.31-20.57) and install it, I reboot and grub will default choose the new kernel (perfect). The boot process stop when the following error is received:
udevd [xx]: segfult .... error 6 in libc.so.6 Segmentation fault

I tried the compilation several times, but still with no luck. Would you please guide me if I'm missing anything or whether the new version (20.57) is not compatible with this description.

Note: I'm changing the configuration of the kernel with quite few things:
- Select the Configure standard kernel features (for small systems) from General Setup
- Disable Power management AND ACPI options
- Disable DMA engine support form Device Drivers
- Disable some of the Ubuntu supplied third-party device drivers

Once again, thanks for the super blog, and one more thanks for helping me.

Re: How to compile a kernel for Ubuntu Karmic

Saint DanBert — Fri, 12 Feb 2010 23:20:30 -0000

I really want to do this and REALLY enjoyed the read. As usually, I have questions:

1. There is list of drivers and modules (lsmod &c) that get used on my hardware. What is a good way to create a reasonably complete list so that I don't break something I use? How do I make sure that I have all of the various parts and
back ports and extras and whatever so that everything get built completely and correctly?

2. Is there a good roadmap to help match kernel config parameters with my own hardware and operational requirements?

Thanks,
~~~ 0;-Dan

Re: How to compile a kernel for Ubuntu Karmic

Peter — Fri, 12 Feb 2010 19:38:57 -0000

You don't have to use sudo for the su command, but in Ubuntu direct login as root is disabled (no password is set for the root user making it impossible to login in). When you type su -, you ask to login directly as root and as mentioned, this is disabled by default.

su --> login as root
sudo --> run as root

So by running sudo su -, you basically trick the system, you run su as root and the systems says, ok you are root so no need to ask for a password. To show this try the following:
Open a terminal as a normal user and run su - <youruser> you will be prompted for a password. Now become root and run su - <youruser> no password is required.

Using sudo -i brings environment variables DISPLAY and TERM into the root shell from the user that executes the command and adds the environment variables SUDO_USER and SUDO_UID. In general that is not that big of deal, in our case we could use sudo -i instead of sudo su -.

Re: How to compile a kernel for Ubuntu Karmic

Saint DanBert — Fri, 12 Feb 2010 18:32:58 -0000

I notice that you type "sudo su -" before you perform a series of apt-get commands The "su -" uses set -user to start a login shell ( '-' ) as superuser. This is redundant on a couple of levels. First, one does not to be super user to run "su".
Using "sudo -i" uses the super-user-do command as an interactive shell ( '-i' ). Likewise, "sudo -b" runs the command as a background task.Check out the sudo man-page for details.

If there is a difference between "su -" and "sudo -i" I have not found any operational reason. I prefer and recommend "sudo -" because there is logging whereas "su -" has none.

Another man's thoughts,
~~~ 0;-Dan

Re: How to compile a kernel for Ubuntu Karmic

Peter — Sun, 07 Feb 2010 18:12:02 -0000

If you want to change the configuration I do believe you'll have to compile the kernel all over again.
By recompiling you won't have conflicts, what you could do to keep track of your configurations is make backups of every configuration under a different name.

Re: How to compile a kernel for Ubuntu Karmic

Chris — Sun, 07 Feb 2010 02:05:43 -0000

Thank you for this good article. I was able to compile my own kernel with your help.

How would be the workflow for compiling several versions of the kernel with different configurations? I want to change the configuration frequently (for finding out what's good and what is not) without recompiling everything and without conflicts in the package manager or elsewhere. Would be nice if you could help me with that.