Fedora Kernel Building Information

Current Version at time of writing: Fedora 12

New Info:

http://fedoraproject.org/wiki/Building_a_custom_kernel (info for fedora > 8)

Old Info:

http://www.mjmwired.net/

http://www.mjmwired.net/resources/mjm-fedora-fc5.html#kernelsrc

     the above links shows how to download the fedora kernel source

http://www.howtoforge.com/kernel_compilation_fedora

     the above link explains how to build a fedora rpm kernel

http://fedoraproject.org/wiki/Docs/CustomKernel

Obtaining Kernel Source through 'yum'

There are yum utilities which will download the LATEST kernel source.

You only have to install yum-utils once:

[root@maltsweb kernel-source]# yum install yum-utils

Download the new kernel source:

[root@maltsweb kernel-source]# yumdownloader --source kernel --enablerepo core-source --enablerepo updates-source

Install the SRC.RPM file and Prepare source

Install the kernel.src.rpm that you chose to install in the previous steps.

Install:

[root@maltsweb kernel-source]# rpm -Uvh kernel-2.6.15-1.1955_FC5.src.rpm
   1:kernel                 ########################################### [100%]

Install any dependencies that our kernel build might have:

# yum-builddep kernel

Set it up:

First we need to “brand” our custom kernel:

[root@maltsweb kernel-source]# vi /usr/src/redhat/SPECS/kernel-2.6.spec

And change:

- #% define dist .XX
+ %define dist .www

And finally run:

[root@maltsweb kernel-source]# rpmbuild -bp --target=$(uname -m)  /usr/src/redhat/SPECS/kernel-2.6.spec

This is when you prepare patches, new configs, etc.

cd SOURCES/*
make menuconfig

Build the RPM:

# cd SPECS/
# rpmbuild -bb --target=$(uname -m) --with firmware --without debug --without debuginfo --without devel kernel.spec

Install the RPM:

cd RPMS/i386
rpm -ivh kernel-2.6.20www1.2316-2.i386.rpm

mkinitrd /boot/initrd-2.6.20-www1.2316-2.img 2.6.20-www1.2316

vi /boot/grub/menu.lst

#title Fedora Core (2.6.20-1.2316.fc5smp)
#       root (hd0,0)
#       kernel /vmlinuz-2.6.20-1.2316.fc5smp ro root=/dev/VolGroup00/LogVol00 rhgb quiet
#       initrd /initrd-2.6.20-1.2316.fc5smp.img

title Fedora Core (2.6.20-www1.2316)
        root (hd0,0)
        kernel /vmlinuz-2.6.20-www1.2316 ro root=/dev/VolGroup00/LogVol00 rhgb quiet
        initrd /initrd-2.6.20-www1.2316-2.img

Reboot using the new kernel (and leave the old one installed just incase).

Run the following to verify that the new kernel is loaded:

[john@maltsweb ~]$ uname -r
2.6.20-www1.2316

Now, view the currently installed kernels:

[root@maltsweb john]# rpm -q kernel
kernel-2.6.20www1-1
kernel-2.6.20www1.2316-2

select the kernel you wish to remove (kernel-2.6.20www1-1 in this case, since the other kernel looks similar to the currently running kernel) and remove it:

[root@maltsweb john]# rpm -e --nodeps kernel-2.6.20www1-1
[root@maltsweb john]#

You should probably remove the source of your previous kernel build prior to building the new kernel.

[root@maltsweb ~]# cd /usr/src/redhat/BUILD/
[root@maltsweb BUILD]# ls
kernel-2.6.20  kernel-2.6.20www1.2316
[root@maltsweb BUILD]# ls -l
total 16
drwxr-xr-x  5 root root 4096 May 15 18:33 kernel-2.6.20
drwxr-xr-x 21 root root 4096 May 15 18:25 kernel-2.6.20www1.2316
[root@maltsweb BUILD]# uname -r
2.6.20-www1.2316
[root@maltsweb BUILD]#

The above shows that I currently have the kernel-2.6.20 source code, and a custom build for kernel-2.6.20www1.2316, which matches the currently running kernel. So when I upgrade my kernel, before I start I can remove the custom kernel directory:

[root@maltsweb BUILD]# rm -Rf kernel-2.6.20www1.2316/
[root@maltsweb BUILD]#

This should clear up enough space to build a new kernel.