Re: [gentoo-user] Problem with "make oldconfig" 2.6.30-8 ==> 2.6.31

[Tanstaafl]

On 2010-03-10 8:47 AM, Neil Bothwick wrote:
> On Wed, 10 Mar 2010 08:22:41 -0500, Tanstaafl wrote:
>
>>> Today is when running a lilo menu with "production" and "experimental"
>>> kernels saved me.  "production" is 2.6.30-r8.  "experimental" is
>>> 2.6.31-r6 or 2.6.31-r10 (same problems with either one).  I set
>>> /usr/src/linux to point at 2.6.31-r6 (or 10), copied .config from
>>> 2.6.30-r8 and ran "make oldconfig".
>>
>> I *never* use make oldconfig between major kernel versions...
>
> The .30, .31 is the minor kernel version. You shouldn't use oldconfig
> when going from 2.4 to 2.6 but from 2.6.m to 2.6.n is safe.

Again, not according to the official upgrade guide - it specifically
uses 2.6.9-r1 to 2.6.9-r2 as an example of a 'minor' update, and going
from 2.6.8 to 2.6.9 as having potentially 'too large of changes for make
oldconfig to be considered safe'.

If the guide is outdated, maybe it should be updated:

http://www.gentoo.org/doc/en/kernel-upgrade.xml#doc_chap10

"10.  Advanced: Using your old kernel .config to configure a new one

It is sometimes possible to save time by re-using the configuration file
from your old kernel when configuring the new one. Note that this is
generally unsafe -- too many changes between every kernel release for
this to be a reliable upgrade path.

The only situation where this is appropriate is when upgrading from one
Gentoo kernel revision to another. For example, the changes made between
gentoo-sources-2.6.9-r1 and gentoo-sources-2.6.9-r2 will be very small,
so it is usually OK to use the following method. However, it is not
appropriate to use it in the example used throughout this document:
upgrading from 2.6.8 to 2.6.9. Too many changes between the official
releases, and the method described below does not display enough context
to the user, often resulting in the user running into problems because
they disabled options that they really didn't want to.

To reuse your old .config, you simply need to copy it over and then run
make oldconfig. In the following example, we take the configuration from
gentoo-sources-2.6.9-r1 and import it into gentoo-sources-2.6.9-r2.

Code Listing 10.1: Reusing your old config

# cd /usr/src/linux-2.6.9-gentoo-r2
# cp ../linux-2.6.9-gentoo-r1/.config .
# make oldconfig

<snip>

At this point, you may be asked to produce answers for configuration
options which have changed between the two versions. Once you have done
that, you can compile and install your kernel as normal, without having
to go through the menuconfig configuration process.

A much safer upgrading method is to copy your config as previously
shown, and then simply run make menuconfig. This avoids the problems of
make oldconfig mentioned previously, as make menuconfig will load up
your previous configuration as much as possible into the menu. Now all
you have to do is go through each option and look for new sections,
removals, and so on. By using menuconfig, you gain context for all the
new changes, and can easily view the new choices and review help screens
much easier. You can even use this for upgrades such as 2.6.8 to 2.6.9;
just make sure you read through the options carefully. Once you've
finished, compile and install your kernel as normal."

-- 

Charles