Bisecting the Kernel
I’m sure there are maaany ways to bisect the ubuntu kernel, here is what I do.
1. Space setup
I would advise that whatever machine you are running on has a decently size persistent disk attached to act as your workdir. This will give you more space and mean that, if you thoroughly F this up, you can trash the world without losing anything :).
If you have yet to narrow down to a particular version, you don’t need to start compiling just now as you can still work with pre-compiled releases from the ubuntu mainline.
Once you have found the official version which contains the problem, you can see a list of the commits which went into it on the ubuntu mainline version page, eg: v4.14.60 changes. You can also find further details of the commits at http://cdn.kernel.org/pub/linux/kernel/.
2. Let’s get started!
# set yourself up mkdir -p $HOME/kern/source && cd $HOME/kern/source # takes forever git clone git://git.launchpad.net/~ubuntu-kernel-test/ubuntu/+source/linux/+git/mainline-crack cd mainline-crack git log --oneline v<last-known-good>..v<current-bad-version> # eg v4.14.59..v4.14.60 # choose some sensible sha in the middle, or one that just looks suspicious if you know what you are after git checkout <sha> # wget any patches from http://kernel.ubuntu.com/~kernel-ppa/mainline/<VERSION>/, and then... patch -p1 < 0001-base-packaging.patch etc # copy your existing kernel config so that you don't accidentally upset something else and distract you from your problem cp /boot/config-$(uname -r) .config make oldconfig # start building some custom debs, DON'T forget to name the custom kernel after the sha you are building from, it will be helpful make clean make -j `getconf _NPROCESSORS_ONLN` deb-pkg LOCALVERSION=-custom-<sha> # if your `/` is small and you don't have power to increase it, bind mount a modules dir backed by your persistent disk over the real one so that you don't flood it mkdir $HOME/kern/modules/v4.14.59-custom-<sha> mkdir /lib/modules/v4.14.59-custom-<sha> mount --bind $HOME/kern/modules/v4.14.59-custom-<sha> /lib/modules/v4.14.59-custom-<sha> # make modules make modules_install -j `getconf _NPROCESSORS_ONLN` # move your custom debs to a sensible location mkdir $HOME/kern/custom-comp/v4.14.59-custom-<sha> mv *.deb ../../custom-comp/v4.14.59-custom-<sha>
To use your newly compiled kernel just perform the same steps as in Switching the Kernel.