Comment 72 for bug 447892

On Fri, Jan 1, 2010 at 9:43 AM, Olie <email address hidden> wrote:
> I am not much of a kernel hacker, I will be happy to test anything, but
> I need help from someone to find the specific change from .1 to .2 that
> causes the problem.

I can guide you through it. I did it for the first time last week, and
it wasn't too hard.

First, it is probably a good idea to compile 2.6.31.1 and 2.6.31.2
yourself and confirm your findings with the self-built kernels. To do
this, follow the instructions at
https://wiki.ubuntu.com/KernelTeam/GitKernelBuild except that instead
of
git clone git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git
you do
git clone git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-2.6.31.y.git
in order to check out the 2.6.31 stable tree.
After step 3 (cd linux-2.6) you do
git checkout v2.6.31.1
in order to get the source to 2.6.31.1. Then you can follow the rest
of the recipe to build that kernel.
After you have done that and have the deb-files you do a
git checkout v2.6.31.2
and start again on step 5 (make oldconfig).

Once you have done this (or right away if you feel like skipping it),
instead of using git checkout, use
git bisect start v2.6.31.2 v2.6.31.1
(the man page for git-bisect is quite good, consult it if I mess up
something in the explanation)
This will check out a version in the middle between 2.6.31.1 and
2.6.31.2. Start on step 5 again. install the deb-files, test if the
kernel freezes and if it does, enter the linux-2.6 directory again and
write
git bisect bad
or if it does not freeze:
git bisect good
It will then check out another mid-point and you start on step 5 again.

I think this should be enough information to do it, but don't hesitate
if you have any more questions.

PS: The time consuming parts of the procedure is the git clone part
(has to download several hundred megabytes) and the make-kpkg
kernel_image kernel_headers part (step 8) which builds the kernel. The
kernel build takes about an hour on my dual-core laptop. It will
probably take a lot longer on yours.

PPS: You can the list of commits leading up to 2.6.31.2 at
http://git.kernel.org/?p=linux/kernel/git/stable/linux-2.6.31.y.git;a=shortlog;h=a2822cac80be9e7fc83eaf9b7d17f169eabd4c99
The v2.6.31.1 tag is on the second page.