where is the kernel code?

[Mario Basanta]

hi,

i am trying to access the modules sources code but the folder lib/modules doesn't seem to exist in the linux shell. Also i am unable to install the linux headers package:

sudo apt-get install linux-headers-$(uname -r)
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
E: Unable to locate package linux-headers-5.4.163-17384-g99ca1c60d20c
E: Couldn't find any package by glob 'linux-headers-5.4.163-17384-g99ca1c60d20c'
E: Couldn't find any package by regex 'linux-headers-5.4.163-17384-g99ca1c60d20c'

what could i be missing? this is my system information:

CHROME VERSION

98.0.4758.107

CHROMEOS_ARC_ANDROID_SDK_VERSION

28

CHROMEOS_ARC_POLICY

CHROMEOS_ARC_POLICY_COMPLIANCE_REPORT

CHROMEOS_ARC_STATUS

enabled

CHROMEOS_ARC_VERSION

8186397

CHROMEOS_AUSERVER

https://tools.google.com/service/update2

CHROMEOS_BOARD_APPID

{9A3BE5D2-C3DC-4AE6-9943-E2C113895DC5}

CHROMEOS_CANARY_APPID

{90F229CE-83E2-4FAF-8479-E368A34938B1}

CHROMEOS_DEVSERVER

CHROMEOS_FIRMWARE_VERSION

Google_Ampton.11297.288.0

CHROMEOS_RELEASE_APPID

{9A3BE5D2-C3DC-4AE6-9943-E2C113895DC5}

CHROMEOS_RELEASE_BOARD

octopus-signed-mp-v31keys

CHROMEOS_RELEASE_BRANCH_NUMBER

61

CHROMEOS_RELEASE_BUILDER_PATH

octopus-release/R98-14388.61.0

CHROMEOS_RELEASE_BUILD_NUMBER

14388

CHROMEOS_RELEASE_BUILD_TYPE

Official Build

CHROMEOS_RELEASE_CHROME_MILESTONE

98

CHROMEOS_RELEASE_DESCRIPTION

14388.61.0 (Official Build) stable-channel octopus

CHROMEOS_RELEASE_KEYSET

mp-v31

CHROMEOS_RELEASE_NAME

Chrome OS

CHROMEOS_RELEASE_PATCH_NUMBER

0

CHROMEOS_RELEASE_TRACK

stable-channel

CHROMEOS_RELEASE_UNIBUILD

1

CHROMEOS_RELEASE_VERSION

14388.61.0

CLIENT_ID

error: consent not given

ENTERPRISE_ENROLLED

Not managed

GOOGLE_RELEASE

14388.61.0

Thanks!

[Mike Frysinger]

what env are you running here ?  CrOS itself doesn't use `apt-get`.

-mike

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[Dmitry Torokhov]

This must be Crostini and we do not support modifying the kernel or installing additional kernel modules in Crostini environment.

Thanks,

Dmitry

[Mario Basanta]

I am running Chrome OS in a Asus Chromebook C214MA , Also i enabled the linux development feature. Now what i want to do is ,be able to find the kernel folder like i do in other linux distros lib/module/ , it’s that possible to do from the OS, or i need to use the dev environment of CrOs? 

Thanks,

--

Atte
Ing Mario Basanta

[Daniel Verkamp]

The Crostini VM kernel is built from the ChromeOS kernel source tree,
rather than a Debian kernel, so using $(uname -r) will not find a
corresponding Debian linux-headers package. If you have software that
requires Linux headers to build, you can try installing a
linux-headers package with a similar version, but software that
requires kernel headers to build is likely not going to work as
described below.

The Crostini VM environment (aka termina) is currently using Linux
5.10, and it uses a kernel configuration from here:
https://source.chromium.org/chromiumos/chromiumos/codesearch/+/main:src/third_party/kernel/v5.10/chromeos/config/termina/
(You can find the whole kernel source tree in the parent v5.10
directory.)
This has recently been reorganized to use the splitconfig
infrastructure, so the final configuration is derived from a default
set of configuration options combined with the termina base.config
plus the architecture-specific configs. You can extract the actual
running configuration using `zcat /proc/config.gz` within Crostini.

As Dmitry mentioned, the termina kernel is built without module
support (CONFIG_MODULES=n), so all necessary drivers are built in, and
there are no modules associated with this kernel. Therefore the
/lib/modules directory does not need to exist.

This also means you cannot build or install custom kernel modules for
the Crostini kernel:
https://chromium.googlesource.com/chromiumos/docs/+/HEAD/containers_and_vms.md#Can-I-install-custom-kernel-modules

If you have a Chromium OS development environment
(https://chromium.googlesource.com/chromiumos/docs/+/main/developer_guide.md),
you can modify and build Crostini yourself and deploy it on a
developer-mode Chromebook
(https://chromium.googlesource.com/chromiumos/docs/+/HEAD/crostini_developer_guide.md),
although this is probably not what you are looking for exactly.

Thanks,
-- Daniel

[Mario Basanta]

Thanks All for your help,

Daniel, i will try what you said, is a longer path but at the end it might allow me to run a new module in the kernel.



> On Mar 30, 2022, at 5:28 AM, Daniel Verkamp <dver...@chromium.org> wrote:
>
> The Crostini VM kernel is built from the ChromeOS kernel source tree,