First ensure you have all dependencies correctly setup:
sudo apt-get install libvirt-bin qemu-kvm cpu-checker virtinst uvtool git sudo apt-get build-dep linux-image-`uname -r`
Ensure kvm works:
kvm-ok
In this example we are using uvtool to create VMs using cloud images, but you could just as easily use a preseed install or a manual install via an ISO.
First sync the cloud image:
uvt-simplestreams-libvirt sync release=trusty arch=amd64
Clone the necessary git directory:
git clone git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git linux.git
Copy ktest.pl outside of the linux kernel (since bisecting it also changes the script, this way it remains constant):
cd linux cp tools/testing/ktest/ktest.pl cp -r tools/testing/ktest/examples/include .. cd ..
Create directories for script:
mkdir configs build mkdir configs/ubuntu build/ubuntu
Get an appropriate config for the bisect you are using and ensure it can reasonable 'make oldconfig' with the kernel version you are using. For example, if we are bisecting v3.4 kernels, we can use an Ubuntu v3.5 series kernel config and yes '' | make oldconfig to ensure it is very close. Put this config into configs/ubuntu/config-min. For convenience I have a put a config that works here for this example:
http://people.canonical.com/~arges/amd64-config.flavour.generic
Create the VM, ensure you have ssh keys setup on your local machine first:
uvt-kvm create ubuntu release=trusty arch=amd64 --password ubuntu --unsafe-caching
Ensure the VM can be ssh'ed to via 'ssh ubuntu@ubuntu':
echo "$(uvt-kvm ip ubuntu) ubuntu" | sudo tee -a /etc/hosts
SSH into VM with ssh ubuntu@ubuntu.
Set up the initial target kernel to boot on the VM:
sudo cp /boot/vmlinuz-`uname -r` /boot/vmlinuz-test sudo cp /boot/initrd.img-`uname -r` /boot/initrd.img-test
Ensure SUBMENUs are disabled on the VM, as the grub2 detection script in ktest.pl fails with submenus, and update grub.
echo "GRUB_DISABLE_SUBMENU=y" | sudo tee -a /etc/default/grub sudo update-grub
Ensure we have a serial console on the VM with /etc/init/ttyS0.conf, and ensure that agetty automatically logs in as root. If you ran with the above script you can do the following:
sudo sed -i 's/exec \/sbin\/getty/exec \/sbin\/getty -a root/' /etc/init/ttyS0.conf
Ensure that /root/.ssh/authorized_keys on the VM contains the host keys so that ssh root@ubuntu works automatically. If you are using the above commands you can do:
sudo sed -i 's/^.*ssh-rsa/ssh-rsa/g' /root/.ssh/authorized_keys
Finally add a test case to /home/ubuntu/test.sh inside of the ubuntu VM. Ensure it is executable.
#!/bin/bash # Make a unique string STRING=$(cat /dev/urandom | tr -dc 'a-zA-Z0-9' | head -c 32) > /var/log/syslog echo $STRING > /dev/kmsg # Wait for things to settle down... sleep 5 grep $STRING /var/log/syslog # This should return 0.
Now exit out of the machine and create the following configuration file for ktest.pl called ubuntu.conf. This will bisect from v3.4 (good) to v3.5-rc1 (bad), and run the test case that we put into the VM.
# Setup default machine
MACHINE = ubuntu
# Use virsh to read the serial console of the guest
CONSOLE = virsh console ${MACHINE}
CLOSE_CONSOLE_SIGNAL = KILL
# Include defaults from upstream
INCLUDE include/defaults.conf
DEFAULTS OVERRIDE
# Make sure we load up our machine to speed up builds
BUILD_OPTIONS = -j8
# This is required for restarting VMs
POWER_CYCLE = virsh destroy ${MACHINE}; sleep 5; virsh start ${MACHINE}
# Use the defaults that update-grub spits out
GRUB_FILE = /boot/grub/grub.cfg
GRUB_MENU = Ubuntu, with Linux test
GRUB_REBOOT = grub-reboot
REBOOT_TYPE = grub2
DEFAULTS
# Do a simple bisect
TEST_START
RUN_TEST = ${SSH} /home/ubuntu/test.sh
TEST_TYPE = bisect
BISECT_GOOD = v3.4
BISECT_BAD = v3.5-rc1
CHECKOUT = origin/master
BISECT_TYPE = test
TEST = ${RUN_TEST}
BISECT_CHECK = 1
Now we should be ready to run the bisection (this will take many, many hours depending on the speed of your machine):
./ktest.pl ubuntu.conf
