[gentoo-user] Kernel upgrade confusion

[gentoo-user] Kernel upgrade confusion

[Jalus Bilieyich]

Recently there was a kernel update and I don't want to reconfigure it
from scratch. In the official documentation, it told me to move the old
.config into the new kernel source tree and type
make oldconfig

This is where I'm confused; which .config file (/proc/config.gz or
/boot/config) and where in the kernel source tree do I put this file in.

Re: [gentoo-user] Kernel upgrade confusion

[Wol's lists]

On 30/12/17 18:43, Jalus Bilieyich wrote:
> Recently there was a kernel update and I don't want to reconfigure it
> from scratch. In the official documentation, it told me to move the old
> .config into the new kernel source tree and type
> make oldconfig
> 
> This is where I'm confused; which .config file (/proc/config.gz or
> /boot/config) and where in the kernel source tree do I put this file in.
> 
> 
/usr/src/linux/.config

Cheers,
Wol

Re: [gentoo-user] Kernel upgrade confusion

[Andrew Barchuk]

Hi Jalus,

> This is where I'm confused; which .config file (/proc/config.gz or
> /boot/config)

The two should have the same content most of the time. You can use
either. config.gz needs to be decompressed (e.g. with zcat).

> where in the kernel source tree do I put this file in.

In the root of the kernel source tree which is /usr/src/linux if the new
kernel is set with eselect kernel.

Make sure to read https://wiki.gentoo.org/wiki/Kernel/Upgrade which
explains all these steps in detail.

---
Andrew

Re: [gentoo-user] Kernel upgrade confusion

[Mick]

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Hi Jalus,

On Saturday, 30 December 2017 18:43:12 GMT Jalus Bilieyich wrote:
> Recently there was a kernel update and I don't want to reconfigure it
> from scratch. In the official documentation, it told me to move the old
> .config into the new kernel source tree and type
> make oldconfig
> 
> This is where I'm confused; which .config file (/proc/config.gz or
> /boot/config) and where in the kernel source tree do I put this file in.

You will need to *copy* your old/existing kernel .config file to the new 
kernel source directory.

Where you copy it from depends on where you have stored your previous kernel 
.config file.  It may be in your /boot, if you have copied it there from /usr/
src/linux/.config last time you compiled your kernel.  It should be in /usr/
src/linux/ if this symlink is still pointing to your previous kernel.  You may 
be able to obtain it from your /proc/config.gz if you have configured your 
kernel to use this option.

So, as root you would for example do:

cp /usr/src/linux-4.4.87-r1/.config /usr/src/linux/4.9.49-r1/ && \
rm /usr/src/linux && \
ln -s /usr/src/linux-4.9.49-r1 linux && \
cd /usr/src/linux && \
make oldconfig

to copy the existing .config into the new kernel sources directory,
to remove the symlink pointing to the previous kernel,
to create a new symlink to the new kernel sources directory,
to change your working directory into the new kernel source tree, and
finally to run make oldconfig in order to configure any new options available 
in kernel 4.9.49-r1, without having to reconfigure each and every option 
already set in your kernel 4.4.87-r1.

If you have a /proc/config.gz you can unpack it and redirect it to your new 
kernel source directory:

zcat /proc/config.gz > /usr/src/linux-4.9.49-r1/.config

before you proceed with the last four steps I showed above.

HTH.
-- 
Regards,
Mick

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Re: [gentoo-user] Kernel upgrade confusion

[Wol's lists]

On 30/12/17 19:11, Mick wrote:
> to remove the symlink pointing to the previous kernel,
> to create a new symlink to the new kernel sources directory,

Or, to use the supplied gentoo tools ...

eselect kernel list

eselect kernel set n

to see what kernels the system thinks are available, and to change the 
current selected kernel.

Note that "emerge --depclean" will clear out all the files IT KNOWS 
ABOUT in /usr/src, so if you don't clean it out manually it will be full 
of debris from previous kernels - basically all the output of make.

But eselect kernel won't show those as available because depclean clears 
up all the references to them.

Cheers,
Wol

Re: [gentoo-user] Kernel upgrade confusion

[Jalus Bilieyich]

This worked.

Thank you all a thousand times!

Re: [gentoo-user] Kernel upgrade confusion

[Alan McKinnon]

On 30/12/2017 20:43, Jalus Bilieyich wrote:
> Recently there was a kernel update and I don't want to reconfigure it
> from scratch. In the official documentation, it told me to move the old
> .config into the new kernel source tree and type
> make oldconfig
> 
> This is where I'm confused; which .config file (/proc/config.gz or
> /boot/config) and where in the kernel source tree do I put this file in.
> 


Either. As long as the *running* kernel is the one you want to copy
from, the contents are identical. You als very likely have a third copy
is /usr/src/<whatever>, assuming you left the sources intact after
kernel installation (the usual case)

-- 
Alan McKinnon
alan.mckinnon@gmail.com