KernelGitGuide
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= Summary = Git is the new SCM used by the Linux kernel developers. Ubuntu has adopted this tool for our own Linux kernel source code so that we can interact better with the community and the other kernel developers. |
## page was renamed from KernelGitGuide |
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= Getting GIT = To obtain the git binaries, please go to [http://www.kernel.org/pub/software/scm/git-core kernel.org] and download the latest source. Folow the build instructions included, and make sure to install them in a location in your PATH. |
Git is the source code management tool used by the Linux kernel developer community. Ubuntu has adopted this tool for our own Linux kernel source code so that we can interact better with the community and the other kernel developers. |
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= Getting the Ubuntu Linux kernel repo = The Ubuntu Linux kernel git repository is located at rsync://rsync.kernel.org/pub/scm/linux/kernel/git/bcollins/ubuntu-2.6.git. To download a local copy of the repo, use this command: {{{ git clone rsync://rsync.kernel.org/pub/scm/linux/kernel/git/bcollins/ubuntu-2.6.git ubuntu-2.6 |
== Current GIT Trees == All of the current live Ubuntu kernel repositories are at the URL below: {{{ http://kernel.ubuntu.com/git-repos/ |
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This will take some time depending on your connection. There's around 110Megs of data to download currently (and this always increases). | There is a tree for each of the currently supported releases as well as any open development and upcoming releases: |
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Once this is complete, you can keep your tree up-to-date by running this command: {{{ git pull |
|| maverick || git://kernel.ubuntu.com/ubuntu/ubuntu-maverick.git || || lucid || git://kernel.ubuntu.com/ubuntu/ubuntu-lucid.git || || karmic || git://kernel.ubuntu.com/ubuntu/ubuntu-karmic.git || || jaunty || git://kernel.ubuntu.com/ubuntu/ubuntu-jaunty.git || || hardy || git://kernel.ubuntu.com/ubuntu/ubuntu-hardy.git || || dapper || git://kernel.ubuntu.com/ubuntu/ubuntu-dapper.git || Typically the distro kernel is on the master branch in these repositories. A number of releases also have other [[KernelTeam/TopicBranches|Topic Branches]] which represent other related but divergent kernels for other purposes. To find out what else is available try browsing http://kernel.ubuntu.com/git and searching for ubuntu). == Installing GIT == To obtain the git binaries, simply install the `git-core` package: {{{ sudo apt-get install git-core}}} '''Use apt-get because other tools such as aptitude will autoremove packages that have no install links.''' '''Note that the `git` package is an entirely different tool which will not do what you want.''' <<Include(Kernel/Action/GitTheSource)>> == Maintaining local changes == During development, the kernel git repository is being constantly rebased against Linus' tree. IOW, Ubuntu specific changes are not being ''merged'', but rather popped off, the tree updated to mainline, and then the Ubuntu specific changes reapplied; they are rebased. There are two ways to track the kernel git tree, depending on whether you have local changes or not: '''No Local Changes''' {{{ git fetch git reset --hard origin/master |
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'''Preserve Local Changes''' {{{ git fetch git rebase --onto origin/master origin/master@{1} }}} == Pushing changes to the main repo == Since the main repo is not publicly writable, the primary means for sending patches to the kernel team is using ''git format-patch''. The output from this command can then be sent to the [[mailto:kernel-team@lists.ubuntu.com|kernel-team]] mailing list. Alternatively, if you have a publicly available git repository for which changes can be pulled from, you can use ''git request-pull'' to generate an email message to send to the [[mailto:kernel-team@lists.ubuntu.com|kernel-team]] mailing list. == Commit templates == In ''debian/commit-templates/'' there are several templates that must be used when committing changes that you expect to be integrated with the Ubuntu kernel repo. The commit templates contain comments for how to fill out the required information. Also note that all commits must have a Signed-off-by line (the "-s" option to ''git commit''). A typical ''git commit'' command will look like: {{{ git commit -s -F debian/commit-templates/patch -e }}} Note that the -e (edit) option must follow the -F option, else git will not let you edit the commit-template before committing. An example commit log will look like such: {{{ UBUNTU: scsi: My cool change to the scsi subsystem UpstreamStatus: Merged with 2.6.15-rc3 My cool change to the scsi subsystem makes scsi transfers increase magically to 124GiB/sec. Signed-off-by: Joe Cool Hacker <jch@ubuntu.com> }}} == Patch acceptance criteria == In general, Ubuntu will apply the same criteria applicable to upstream kernel. Here is a checklist of reading and tools related to posting kernel patches: * <kernel-directory>/Documentation/SubmittingPatches * <kernel-directory>/scripts/checkpatch.pl * <kernel-directory>/scripts/cleanpatch * <kernel-directory>/scripts/cleanfile * <kernel-directory>/scripts/Lindent If you are creating a new file, it is helpful to run it through ''cleanfile'' and/or ''Linent'' before creating a patch<<BR>> If you have generated a patch, it helps running it through ''checkpatch.pl'' and ''cleanpatch'' if necessary<<BR>> Also, using the commit template described above is a good idea for Ubuntu-specific patches == Developers with access to kernel.ubuntu.com == The kernel team has a ''git'' repo located on ''kernel.ubuntu.com'' (AKA zinc.ubuntu.com) in /srv/kernel.ubuntu.com/git/ubuntu. You can, if you want, create a clone for yourself in your directory, and just have your changes pulled when ready. Suggested way to do this: {{{ git clone -l -n -s /srv/kernel.ubuntu.com/git/ubuntu/ubuntu-jaunty.git vi ubuntu-jaunty/.git/description ( give it a descriptive name ) mv ubuntu-jaunty/.git /srv/kernel.ubuntu.com/git/<user>/my-git-tree.git }}} You can now push your changes to this tree via '''ssh'''. Note the '''-l -n -s''' options do a few special things, mainly making your repo share objects with ours (saves space). Now you need to run ''git update-server-info'' in your tree so that it is available over http transport {{{ cd /srv/kernel.ubuntu.com/git/<user>/my-git-tree.git git update-server-info chmod +x /srv/kernel.ubuntu.com/git/<user>/my-git-tree.git/hooks/post-commit }}} To work on your branch, now clone to your local machine from the same origin tree (not the tree you just created on zinc -- this is only for pushing to): {{{ git clone git://kernel.ubuntu.com/ubuntu/ubuntu-jaunty.git my-tree git remote add zinc ssh://kernel.ubuntu.com/srv/kernel.ubuntu.com/git/<user>/my-git-tree.git <do work> git push zinc maser }}} Suggested method for keeping this tree synced with the ubuntu tree, instead of git pull, is to do: {{{ cd my-tree git fetch origin git rebase origin }}} This will keep your changes on top of the original tree (as opposed to being merged). This is also a good idea because during development (e.g. while following the upstream git repo), we frequently rebase to linux-2.6.git upstream, so the '''HEAD''' is not always suitable for pull/merge. = Git tips and tricks = == Reordering patches == {{{ git rebase -i HEAD~10 }}} allows you to interactively reorder the last 10 patches in your branch. You can also squash some patches together. Just follow the directions at the bottom of the file opened up on typing the command. == .gitconfig == Setting up your $HOME/.gitconfig file can help reduce the number of arguments you need to specify to git commands, and let you specify commonly used remote repositories. {{{ [user] email = sconklin@canonical.com name = "Steve Conklin" signingkey = 0x3A758A1E [sendemail] smtpuser = sconklin@canonical.com envelopesender=sconklin@canonical.com smtpserver = /usr/bin/msmtp }}} Is what I have in my file to set up my email address and email. {{{ [remote "sconklin"] url = "ssh://sconklin@zinc.canonical.com/srv/kernel.ubuntu.com/git/sconklin/ubuntu-karmic.git" fetch = +refs/heads/*:refs/remotes/sconklin/* [remote "drm-2.6"] url = "git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6" fetch = +refs/heads/*:refs/remotes/drm-2.6/* [remote "drm-intel"] url = "git://git.kernel.org/pub/scm/linux/kernel/git/anholt/drm-intel" fetch = +refs/heads/*:refs/remotes/drm-intel/* }}} Sets up the remote repositories that I use most often. With these in the config, I can "git fetch sconklin" in any repo and get that remote. A google search for ".gitconfig" will turn up other useful settings. |
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Please read the documentation included with the git source for more details on using git. | Please read the documentation included with the '''git-core''' package for more details on git commands. A tutorial is also available at http://www.kernel.org/pub/software/scm/git/docs/gittutorial.html. |
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If you are an Ubuntu kernel developer with access to people.ubuntu.com, you can follow the KernelDeveloperGuide to get more information. | For a list of quick git recipes and examples, see KernelTeam/GitCheatSheet. |
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CategoryKernel | CategoryKernel CategoryDocumentation |
Git is the source code management tool used by the Linux kernel developer community. Ubuntu has adopted this tool for our own Linux kernel source code so that we can interact better with the community and the other kernel developers.
Current GIT Trees
All of the current live Ubuntu kernel repositories are at the URL below:
http://kernel.ubuntu.com/git-repos/
There is a tree for each of the currently supported releases as well as any open development and upcoming releases:
maverick
git://kernel.ubuntu.com/ubuntu/ubuntu-maverick.git
lucid
git://kernel.ubuntu.com/ubuntu/ubuntu-lucid.git
karmic
git://kernel.ubuntu.com/ubuntu/ubuntu-karmic.git
jaunty
git://kernel.ubuntu.com/ubuntu/ubuntu-jaunty.git
hardy
git://kernel.ubuntu.com/ubuntu/ubuntu-hardy.git
dapper
git://kernel.ubuntu.com/ubuntu/ubuntu-dapper.git
Typically the distro kernel is on the master branch in these repositories. A number of releases also have other Topic Branches which represent other related but divergent kernels for other purposes.
To find out what else is available try browsing http://kernel.ubuntu.com/git and searching for ubuntu).
Installing GIT
To obtain the git binaries, simply install the git-core package:
sudo apt-get install git-core
Use apt-get because other tools such as aptitude will autoremove packages that have no install links.
Note that the git package is an entirely different tool which will not do what you want.
Obtaining the kernel sources for an Ubuntu release using git
The source for each release is maintained in its own git repository on Launchpad.
The git repository is listed in the Vcs-Git: header in the source package and is of the following form:
git://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/<source package>/+git/<series>
For example, the standard Jammy kernel is available at:
git://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/jammy
There is a tree for each of the currently supported releases as well as any open development and upcoming releases. For example:
focal
git://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/focal
jammy
git://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/jammy
noble
git://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/noble
Replace your intended Ubuntu series in the above URL, and pull the source for the kernels you need.
The distro kernel is always on the master branch in these repositories. Each release also has a master-next branch containing the commits that will go into the master branch and become the next SRU release for that series.
A number of releases also have other source packages which represent other related but divergent kernels for other purposes. For example, there is a specialized AWS kernel available in the linux-aws source package. (Previously these sorts of things were done in Topic Branches and some older kernels and projects still use them.)
If you cannot use the git protocol (perhaps because of a firewall), you can use the slower https protocol. For example:
Obtaining a copy
To obtain a local copy you can simply git clone the repository for the release you are interested in. The git command is part of the git package.
For example to obtain the Jammy tree:
git clone git://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/jammy
This will download several hundred megabytes of data. If you plan on working on more than one kernel release you can save space and time by downloading the upstream kernel tree, and use it as a reference. Note that once these two trees are tied together you cannot simply delete or move the virgin Linus tree without manually updating .git/objects/info/alternates in your Ubuntu kernel tree:
git clone git://kernel.ubuntu.com/ubuntu/linux.git git clone --reference linux git://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/jammy git clone --reference linux git://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/noble
In each case you will end up with a new directory <ubuntu-release> containing the source and the full history which can be manipulated using the git command from within each directory.
If you are an advanced git user, you can also add each Ubuntu series as a remote so that you can have all kernel series you need in a single directory. For example,
git remote add jammy git://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/jammy git fetch jammy git checkout -b jammy --track jammy/master git checkout -b jammy-next --track jammy/master-next
By default you will have the latest version of the kernel tree, the master tree. You can switch to any previously released kernel version using the release tags. To obtain a full list of the tagged versions in the release, use the git tag command below:
$ git tag -l Ubuntu-* Ubuntu-5.4.0-47.51 Ubuntu-5.4.0-48.52 Ubuntu-5.4.0-49.53 Ubuntu-5.4.0-51.56 Ubuntu-5.4.0-52.57 ...
To look at the Ubuntu-5.4.0-52.57 version you can simply checkout a new branch pointing to that version:
git checkout -b temp Ubuntu-5.4.0-52.57
You may then manipulate the release - for example, by adding new commits.
Maintaining local changes
During development, the kernel git repository is being constantly rebased against Linus' tree. IOW, Ubuntu specific changes are not being merged, but rather popped off, the tree updated to mainline, and then the Ubuntu specific changes reapplied; they are rebased. There are two ways to track the kernel git tree, depending on whether you have local changes or not:
No Local Changes
git fetch git reset --hard origin/master
Preserve Local Changes
git fetch git rebase --onto origin/master origin/master@{1}
Pushing changes to the main repo
Since the main repo is not publicly writable, the primary means for sending patches to the kernel team is using git format-patch. The output from this command can then be sent to the kernel-team mailing list.
Alternatively, if you have a publicly available git repository for which changes can be pulled from, you can use git request-pull to generate an email message to send to the kernel-team mailing list.
Commit templates
In debian/commit-templates/ there are several templates that must be used when committing changes that you expect to be integrated with the Ubuntu kernel repo. The commit templates contain comments for how to fill out the required information. Also note that all commits must have a Signed-off-by line (the "-s" option to git commit). A typical git commit command will look like:
git commit -s -F debian/commit-templates/patch -e
Note that the -e (edit) option must follow the -F option, else git will not let you edit the commit-template before committing.
An example commit log will look like such:
UBUNTU: scsi: My cool change to the scsi subsystem UpstreamStatus: Merged with 2.6.15-rc3 My cool change to the scsi subsystem makes scsi transfers increase magically to 124GiB/sec. Signed-off-by: Joe Cool Hacker <jch@ubuntu.com>
Patch acceptance criteria
In general, Ubuntu will apply the same criteria applicable to upstream kernel. Here is a checklist of reading and tools related to posting kernel patches:
<kernel-directory>/Documentation/SubmittingPatches
<kernel-directory>/scripts/checkpatch.pl
<kernel-directory>/scripts/cleanpatch
<kernel-directory>/scripts/cleanfile
<kernel-directory>/scripts/Lindent
If you are creating a new file, it is helpful to run it through cleanfile and/or Linent before creating a patch
If you have generated a patch, it helps running it through checkpatch.pl and cleanpatch if necessary
Also, using the commit template described above is a good idea for Ubuntu-specific patches
Developers with access to kernel.ubuntu.com
The kernel team has a git repo located on kernel.ubuntu.com (AKA zinc.ubuntu.com) in /srv/kernel.ubuntu.com/git/ubuntu.
You can, if you want, create a clone for yourself in your directory, and just have your changes pulled when ready.
Suggested way to do this:
git clone -l -n -s /srv/kernel.ubuntu.com/git/ubuntu/ubuntu-jaunty.git vi ubuntu-jaunty/.git/description ( give it a descriptive name ) mv ubuntu-jaunty/.git /srv/kernel.ubuntu.com/git/<user>/my-git-tree.git
You can now push your changes to this tree via ssh. Note the -l -n -s options do a few special things, mainly making your repo share objects with ours (saves space).
Now you need to run git update-server-info in your tree so that it is available over http transport
cd /srv/kernel.ubuntu.com/git/<user>/my-git-tree.git git update-server-info chmod +x /srv/kernel.ubuntu.com/git/<user>/my-git-tree.git/hooks/post-commit
To work on your branch, now clone to your local machine from the same origin tree (not the tree you just created on zinc -- this is only for pushing to):
git clone git://kernel.ubuntu.com/ubuntu/ubuntu-jaunty.git my-tree git remote add zinc ssh://kernel.ubuntu.com/srv/kernel.ubuntu.com/git/<user>/my-git-tree.git <do work> git push zinc maser
Suggested method for keeping this tree synced with the ubuntu tree, instead of git pull, is to do:
cd my-tree git fetch origin git rebase origin
This will keep your changes on top of the original tree (as opposed to being merged). This is also a good idea because during development (e.g. while following the upstream git repo), we frequently rebase to linux-2.6.git upstream, so the HEAD is not always suitable for pull/merge.
Git tips and tricks
Reordering patches
git rebase -i HEAD~10
allows you to interactively reorder the last 10 patches in your branch. You can also squash some patches together. Just follow the directions at the bottom of the file opened up on typing the command.
.gitconfig
Setting up your $HOME/.gitconfig file can help reduce the number of arguments you need to specify to git commands, and let you specify commonly used remote repositories.
[user] email = sconklin@canonical.com name = "Steve Conklin" signingkey = 0x3A758A1E [sendemail] smtpuser = sconklin@canonical.com envelopesender=sconklin@canonical.com smtpserver = /usr/bin/msmtp
Is what I have in my file to set up my email address and email.
[remote "sconklin"] url = "ssh://sconklin@zinc.canonical.com/srv/kernel.ubuntu.com/git/sconklin/ubuntu-karmic.git" fetch = +refs/heads/*:refs/remotes/sconklin/* [remote "drm-2.6"] url = "git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6" fetch = +refs/heads/*:refs/remotes/drm-2.6/* [remote "drm-intel"] url = "git://git.kernel.org/pub/scm/linux/kernel/git/anholt/drm-intel" fetch = +refs/heads/*:refs/remotes/drm-intel/*
Sets up the remote repositories that I use most often. With these in the config, I can "git fetch sconklin" in any repo and get that remote.
A google search for ".gitconfig" will turn up other useful settings.
More information
Please read the documentation included with the git-core package for more details on git commands. A tutorial is also available at http://www.kernel.org/pub/software/scm/git/docs/gittutorial.html.
For a list of quick git recipes and examples, see KernelTeam/GitCheatSheet.
KernelTeam/KernelGitGuide (last edited 2010-06-28 23:55:41 by c-76-105-148-120)