How do I get the kernel source code?
I am planning to write some device drivers and I need to get the Linux kernel source. My Linux kernel version is 3.2.0-23-generic-pae and I downloaded the image from this. In many of the articles I have read, it tells me that I need to have the entire kernel tree to start inserting new modules. Is it enough if I download this image and paste it into the usr/src/ folder or do I have to do something else?
I usually just install the ‘linux-source’ package from synaptic when I’m custom compiling for one of my machines, but given you’re doing development you might need the most recent version. This link might be useful to you: help.ubuntu.com/community/Kernel/Compile
5 Answers 5
This will get the source of the stock kernel:
apt-get source linux-source You can check what version of the kernel is running like this:
Which will print something like:
You can find a list of current source package versions available on your system via:
apt-cache search linux-source To get the upstream version of the kernel:
git clone git://kernel.ubuntu.com/ubuntu/ubuntu-trusty.git In the above link, ‘trusty’ is the codename for the version of Ubuntu. You can find out the codename for the version of Ubuntu you have installed via:
If I use git to clone how do i specify the version. Also If i Clone it is it enough if a I copy pate it into the usr/src folder
That git repository is kept to 3.2.0 specifically; it follows what’s in Ubuntu Precise (12.04). If you want a different version change ubuntu-precise.git to ubuntu-quantal.git or whatever. It should be fine to just copy into usr/src.
And where should I be able to find the source tree when installing with. Damn, I should read better. The answer says apt-get source not apt-get install . Than the source tree will end up in your current path.
sudo apt install linux-source # downloads into system directory sudo apt source linux-source # downloads into working directory If you’re told to give some ‘sources’ URLs in your sources.list , go edit your /etc/apt/sources.list file and uncomment the desired deb-src line, for example (if you’re running Xenial):
deb http://fr.archive.ubuntu.com/ubuntu/ xenial main restricted # deb-src http://fr.archive.ubuntu.com/ubuntu/ xenial main restricted Removing the # on this last line enables sources repositories for download, including kernel sources.
- Use modern tools; avoid apt-get .
- These commands download the source code for your current kernel (in my case 4.4.0-75-generic for example).
- When downloaded into system directory, files are stored in /usr/src/linux-source-4.4.0/ (for example).
Doesn’t work for me (but neither does the apt-get version). I’m running Ubuntu 16.04.4, kernel 4.4.0-98-generic. It says, «You must put some ‘source’ URIs in your sources.list». I have no idea how to do that.
Yes thanks. It was a stupid comment from me. I only needed to google the error message. Anyway, have an upvote for your effort.
is the easiest way. It will download the source from your repository — and it’ll be the same as the version you’re running (assuming you haven’t already customised it).
But if you want to find where the source is maintained you can run:
Look for the ‘Vcs-‘ attribute (Version control system). It’ll usually be a git (Vcs-Git) or mercurial repository.
Note — these commands work with any package. Just substitute ‘linux’ with the package you’re interested in. And also note that ‘apt-get source’ doesn’t need sudo access and will dump the source in your current directory.
This requires the machine you are downloading on to match the target machine. Really only works if you have a network. Most of the readers landing on this page won’t have a network (hence why they suddenly need the source). I need it as a tarball on a thumb drive and I don’t have a working apt.
This downloading the src into the CURRENT DIRECTORY on Ubuntu 20.04 LTS, but it downloaded the wrong version of the kernel?? linux-5.4.0 when uname -r = 5.8.0-55-generic
Download source directly from Launchpad
Strangely enough everyone recommends apt-get source which doesn’t work most of the time if you’re looking for a specific kernel version:
Say you need kernel source for 3.19.0-58 :
apt-get source linux-image-3.19.0-58-generic will get the source for the latest kernel in the series: 3.19.0-80 in this case, which is not what you asked for.
1) Give up, install kernel 3.19.0-80 and use apt-get source
2) Get source directly from launchpad:
- Google site:launchpad.net «linux-image-3.19.0-58-generic»
- That should give you the Launchpad Package Page for that version.
- Scroll down, click the «Source:» link, you’re on the Package Source Page now.
- Scroll down and download .tar.gz , .diff.gz , .dsc files:
- There must be a better way.
- You can get the version you want from git, but you’re in for a big download. See «Obtaining the kernel sources for an Ubuntu release using git» in Ubuntu Wiki Kernel Source Code.
Thank you for explaining this so clearly. However, I am still unable to find the source for linux-image-4.15.0-39-generic. This process is needlessly complicated. I’ve tried googling for it but I keep finding packages that are a few kilobytes only. Any tips?
This is the only option on this page that worked for Ubuntu 20.04 LTS to get something that claims to be a similar kernel version linux-5.8.0 to the one returned but uname -r
There are cases where it is simply more practical to download the linux kernel source and headers for the version you’re interested in directly from http://kernel.org (a pretty reliable URL/site that isn’t going away [e.g. standard stackoverflow concern about stale links isn’t not an issue])
Reason? For example, you might be interested in debugging an older/defunct no-longer-supported version of linux where package repository points to dead areas, where in some cases there are either no viable current alternatives, or the repos has are expired keys that won’t let you get the stuff, requiring unmemorable difficult to search out arcane techniques to get those repositories to work anyway.
Or maybe Internet networking might be broken on Linux machine (or VM) you’re using, but file sharing or NFS works, where the source can be downloaded onto another machine and accessed via the filesystem.
If you’re working with a relatively obsolete version of Linux, chances are you’ll have to build a number of things from source and get them the hard way.
Where do I find the version of a Linux kernel source tree?
I have downloaded from a hardware vendor just a tarball of their Linux source tree (no Git repository metadata), is there a way to find out the version number of the kernel? Is the version number usually stored in a file somewhere in the source tree? I’d like to be able to do this without compiling and running the kernel.
6 Answers 6
You can find the version by running
I should have clarified that I want to be able to do this just by examing the source tree rather than attempting to compile an run the kernel if possible. I’ve updated my question accordingly.
Adrian, I suspect it was when you had the uname solution which would require installing the kernel. In any case, since you now have one that doesn’t require a build and install, here’s an upvote for you to counteract the drive-by downvote — I hate them with a vengeance 🙂
@paxdiablo Thanks and probably true — since the OP also edited his question the uname thing became the wrong answer. I just wish people would say — oh well 🙂
Looking at the question edit history, uname was always the wrong answer (the question implied that the hardware to run the kernel might not even be available). But from the original question I would have thought that something that inspected the build outputs would have been acceptable.
Check the top-level Makefile , an example of which is here. At the top of that, you should see something like:
VERSION = 3 PATCHLEVEL = 1 SUBLEVEL = 0 EXTRAVERSION = -pax NAME = Custom Pax Version The (admittedly minor) advantage of this method is that you only need the ability to view the files themselves rather than having to run a build process.
both methods are very good (I mean make kernelversion as well as vi Makefile) as in result before making any module or something depending on the kernel running now it’s important to verify if command uname -r will match the output of make kernelversion and if not to modify with vi Makefile
The major advantage of this method is that you don’t need to clone a large repository just to check the version, when said version is not guessable from the git tag. Thanks.
Yet another solution: in the older times include/linux/version.h , currently include/generated/uapi/linux/version.h , but only after at least a partially successful compilation.
include/linux/version.h is deprecated, it now gets generated during a build in include/generated/uapi/linux/version.h
In the Linux source tree’s root file, check the Makefile content. In its beginning part:
# SPDX-License-Identifier: GPL-2.0 VERSION = 4 PATCHLEVEL = 14 SUBLEVEL = 67 Then you linux source tree’s version is: 4.14.67
In the kernel source tree, check the root directory Makefile to get the kernel version as below. Example as below: $ head Makefile # SPDX-License-Identifier: GPL-2.0 VERSION = 5 PATCHLEVEL = 18 SUBLEVEL = 0 EXTRAVERSION = -rc3 NAME = Superb Owl # *DOCUMENTATION* # To see a list of typical targets execute "make help" # More info can be located in ./README From the above we get the source code version is 5.18.0-rc3 In case someone needs to script it: With awk , the version can be printed from Makefile like this:
awk '/^VERSION =/;/^PATCHLEVEL =/;/^SUBLEVEL =/;/^EXTRAVERSION =/;END' Makefile If the EXTRAVERSION appendix shall be skipped:
awk '/^VERSION =/;/^PATCHLEVEL =/;/^SUBLEVEL =/;END' Makefile If someone knows how to make awk continue with the next pattern if the current pattern has been matched once, that would make it failsafe in case multiple lines start with VERSION = respectively. But I haven’t seen this in any Linux source code version.