From nobody Mon Feb 9 17:08:04 2026 Received: from relay8-d.mail.gandi.net (relay8-d.mail.gandi.net [217.70.183.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 67580345743; Thu, 22 Jan 2026 14:07:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.70.183.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769090844; cv=none; b=ETZgIWnLCmlMTqZWXrdFndltjK2kAS9MGOaoOQ8v2KTp1Mh3Vw75MKpWh/Y4ibP4ZEoCNdsiIW7/UoGaFuz6v94S8Q+ZDWH2FM6lCot3VyM5M2BzOz32Svg+utT/eXcCLrqsBDr4L1ZH1CBwvz/z8hBSSKLIRPVifMB9KadWOoY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769090844; c=relaxed/simple; bh=MPFWzCRMQFvNBBWMESM2u/ts+T7p/a41Aaoq0Z93YoA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=hXShk0z2YE0mMnD2Hlb9IxF9SIOGL2C8Ged8P/sbkabBpuVbhEHBx3fosDd61ESUxHo6VpxG/sQy04QUqbJcJrc5V7twfccKGlhSXvHmsWm7wQfSAdzcgQH4TLLGTuxm6D/YPSRELcg8klueWBTRz0qavqtuaItkcmgNWwIJA9k= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=gtucker.io; spf=pass smtp.mailfrom=gtucker.io; dkim=pass (2048-bit key) header.d=gtucker.io header.i=@gtucker.io header.b=Rud1y+dt; arc=none smtp.client-ip=217.70.183.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=gtucker.io Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gtucker.io Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gtucker.io header.i=@gtucker.io header.b="Rud1y+dt" Received: by mail.gandi.net (Postfix) with ESMTPSA id 3638441DF3; Thu, 22 Jan 2026 14:07:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gtucker.io; s=gm1; t=1769090833; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=WV9yo6vv4rX2CVpVHGPy28S5A9jqZyPD+02tk7gtpU8=; b=Rud1y+dtpT/bj7voBBSMnGGDvn4VTaL5IRHgqhteS2DwWbu5dUf+CtFa4kPxqxdawUlvkA /pC8rOFJvyOjg2Vqd2fIW5qPI3vvPNxJSI+4w9if86BDai56XXzOxDXF4niNVwhwclbrVl DM+wSISOhCigEBIb+ah4ffBX0ohqYpKpZUsjk5GDWYczk4fWK5Li5TUKAkmRLvalImtWTC y0fqy6dBhUxOT1mNhx+2wUXlsn6Fi+78PkMQNAjZ0RDb7LC2mxIB03oMHsc6JXPf2MM2dB CkunDy7M90x0oEp4jM1i2CCVx/eiNaMwJLxSFIMhgFWb3Yva+1TZZspFX8IyUg== From: Guillaume Tucker To: Nathan Chancellor , Nicolas Schier , Miguel Ojeda , David Gow , =?UTF-8?q?Onur=20=C3=96zkan?= Cc: Guillaume Tucker , Arnd Bergmann , linux-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org, linux-kbuild@vger.kernel.org, automated-testing@lists.yoctoproject.org, workflows@vger.kernel.org, llvm@lists.linux.dev Subject: [PATCH v4 2/2] Documentation: dev-tools: add container.rst page Date: Thu, 22 Jan 2026 15:07:00 +0100 Message-ID: X-Mailer: git-send-email 2.47.3 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-GND-Sasl: gtucker@gtucker.io X-GND-Cause: gggruggvucftvghtrhhoucdtuddrgeefgedrtddtgddugeeifeeiucetufdoteggodetrfdotffvucfrrhhofhhilhgvmecuifetpfffkfdpucggtfgfnhhsuhgsshgtrhhisggvnecuuegrihhlohhuthemuceftddunecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenucfjughrpefhvfevufffkffojghfgggtgfesthekredtredtjeenucfhrhhomhepifhuihhllhgruhhmvgcuvfhutghkvghruceoghhtuhgtkhgvrhesghhtuhgtkhgvrhdrihhoqeenucggtffrrghtthgvrhhnpeelvdegheehuedvhfehheevfeekleefgefgieevteeugfdvteeiudduvddvvdfgvdenucffohhmrghinhepughotghkvghrrdhiohdpphhoughmrghnqdguvghskhhtohhprdhiohdpughotghkvghrrdgtohhmpdhkvghrnhgvlhdrohhrghdpghhithhlrggsrdgtohhmnecukfhppedvtddtudemkeeiudemgegrgedtmeekiedvtdemvdeigegsmedurgefheemuggsheegmedufeegvgenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepihhnvghtpedvtddtudemkeeiudemgegrgedtmeekiedvtdemvdeigegsmedurgefheemuggsheegmedufeegvgdphhgvlhhopehrihhnghhordhlrghnpdhmrghilhhfrhhomhepghhtuhgtkhgvrhesghhtuhgtkhgvrhdrihhopdhqihgupeefieefkeeggedufffhfedpmhhouggvpehsmhhtphhouhhtpdhnsggprhgtphhtthhopedufedprhgtphhtthhopehnrghthhgrn heskhgvrhhnvghlrdhorhhgpdhrtghpthhtohepnhhstgeskhgvrhhnvghlrdhorhhgpdhrtghpthhtohepohhjvggurgeskhgvrhhnvghlrdhorhhgpdhrtghpthhtohepuggrvhhiughgohifsehgohhoghhlvgdrtghomhdprhgtphhtthhopeifohhrkhesohhnuhhrohiikhgrnhdruggvvhdprhgtphhtthhopehgthhutghkvghrsehgthhutghkvghrrdhioh X-GND-State: clean X-GND-Score: -100 Add a dev-tools/container.rst documentation page for the scripts/container tool. This covers the basic usage with additional information about environment variables and user IDs. It also includes a number of practical examples with a reference to the experimental kernel.org toolchain images. Update MAINTAINERS accordingly with a reference to the added file. Cc: Nathan Chancellor Cc: Nicolas Schier Cc: Miguel Ojeda Cc: David Gow Cc: "Onur =C3=96zkan" Signed-off-by: Guillaume Tucker Reviewed-by: Onur =C3=96zkan --- Documentation/dev-tools/container.rst | 227 ++++++++++++++++++++++++++ Documentation/dev-tools/index.rst | 1 + MAINTAINERS | 1 + 3 files changed, 229 insertions(+) create mode 100644 Documentation/dev-tools/container.rst diff --git a/Documentation/dev-tools/container.rst b/Documentation/dev-tool= s/container.rst new file mode 100644 index 000000000000..452415b64662 --- /dev/null +++ b/Documentation/dev-tools/container.rst @@ -0,0 +1,227 @@ +.. SPDX-License-Identifier: GPL-2.0-only +.. Copyright (C) 2025 Guillaume Tucker + +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D +Containerized Builds +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D + +The ``container`` tool can be used to run any command in the kernel source= tree +from within a container. Doing so facilitates reproducing builds across +various platforms, for example when a test bot has reported an issue which +requires a specific version of a compiler or an external test suite. While +this can already be done by users who are familiar with containers, having= a +dedicated tool in the kernel tree lowers the barrier to entry by solving c= ommon +problems once and for all (e.g. user id management). It also makes it eas= ier +to share an exact command line leading to a particular result. The main u= se +case is likely to be kernel builds but virtually anything can be run: KUni= t, +checkpatch etc. provided a suitable image is available. + + +Options +=3D=3D=3D=3D=3D=3D=3D + +Command line syntax:: + + scripts/container -i IMAGE [OPTION]... CMD... + +Available options: + +``-e, --env-file ENV_FILE`` + + Path to an environment file to load in the container. + +``-g, --gid GID`` + + Group id to use inside the container. + +``-i, --image IMAGE`` + + Container image name (required). + +``-r, --runtime RUNTIME`` + + Container runtime name. Supported runtimes: ``docker``, ``podman``. + + If not specified, the first one found on the system will be used + i.e. Podman if present, otherwise Docker. + +``-s, --shell`` + + Run the container in an interactive shell. + +``-u, --uid UID`` + + User id to use inside the container. + + If the ``-g`` option is not specified, the user id will also be used f= or + the group id. + +``-v, --verbose`` + + Enable verbose output. + +``-h, --help`` + + Show the help message and exit. + + +Usage +=3D=3D=3D=3D=3D + +It's entirely up to the user to choose which image to use and the ``CMD`` +arguments are passed directly as an arbitrary command line to run in the +container. The tool will take care of mounting the source tree as the cur= rent +working directory and adjust the user and group id as needed. + +The container image which would typically include a compiler toolchain is +provided by the user and selected via the ``-i`` option. The container ru= ntime +can be selected with the ``-r`` option, which can be either ``docker`` or +``podman``. If none is specified, the first one found on the system will = be +used while giving priority to Podman. Support for other runtimes may be a= dded +later depending on their popularity among users. + +By default, commands are run non-interactively. The user can abort a runn= ing +container with SIGINT (Ctrl-C). To run commands interactively with a TTY,= the +``--shell`` or ``-s`` option can be used. Signals will then be received b= y the +shell directly rather than the parent ``container`` process. To exit an +interactive shell, use Ctrl-D or ``exit``. + +.. note:: + + The only host requirement aside from a container runtime is Python 3.10= or + later. + +.. note:: + + Out-of-tree builds are not fully supported yet. The ``O=3D`` option can + however already be used with a relative path inside the source tree to = keep + separate build outputs. A workaround to build outside the tree is to u= se + ``mount --bind``, see the examples section further down. + + +Environment Variables +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D + +Environment variables are not propagated to the container so they have to = be +either defined in the image itself or via the ``-e`` option using an +environment file. In some cases it makes more sense to have them defined = in +the Containerfile used to create the image. For example, a Clang-only com= piler +toolchain image may have ``LLVM=3D1`` defined. + +The local environment file is more useful for user-specific variables added +during development. It is passed as-is to the container runtime so its fo= rmat +may vary. Typically, it will look like the output of ``env``. For exampl= e:: + + INSTALL_MOD_STRIP=3D1 + SOME_RANDOM_TEXT=3DOne upon a time + +Please also note that ``make`` options can still be passed on the command = line, +so while this can't be done since the first argument needs to be the +executable:: + + scripts/container -i docker.io/tuxmake/korg-clang LLVM=3D1 make # won't= work + +this will work:: + + scripts/container -i docker.io/tuxmake/korg-clang make LLVM=3D1 + + +User IDs +=3D=3D=3D=3D=3D=3D=3D=3D + +This is an area where the behaviour will vary slightly depending on the +container runtime. The goal is to run commands as the user invoking the t= ool. +With Podman, a namespace is created to map the current user id to a differ= ent +one in the container (1000 by default). With Docker, while this is also +possible with recent versions it requires a special feature to be enabled = in +the daemon so it's not used here for simplicity. Instead, the container i= s run +with the current user id directly. In both cases, this will provide the s= ame +file permissions for the kernel source tree mounted as a volume. The only +difference is that when using Docker without a namespace, the user id may = not +be the same as the default one set in the image. + +Say, we're using an image which sets up a default user with id 1000 and the +current user calling the ``container`` tool has id 1234. The kernel source +tree was checked out by this same user so the files belong to user 1234. = With +Podman, the container will be running as user id 1000 with a mapping to id= 1234 +so that the files from the mounted volume appear to belong to id 1000 insi= de +the container. With Docker and no namespace, the container will be running +with user id 1234 which can access the files in the volume but not in the = user +1000 home directory. This shouldn't be an issue when running commands onl= y in +the kernel tree but it is worth highlighting here as it might matter for +special corner cases. + +.. note:: + + Podman's `Docker compatibility + `__ + mode to run ``docker`` commands on top of a Podman backend is more comp= lex + and not fully supported yet. As such, Podman will take priority if both + runtimes are available on the system. + + +Examples +=3D=3D=3D=3D=3D=3D=3D=3D + +The TuxMake project provides a variety of prebuilt container images availa= ble +on `Docker Hub `__. Here's the shortest +example to build a kernel using a TuxMake Clang image:: + + scripts/container -i docker.io/tuxmake/korg-clang -- make LLVM=3D1 defco= nfig + scripts/container -i docker.io/tuxmake/korg-clang -- make LLVM=3D1 -j$(n= proc) + +.. note:: + + When running a command with options within the container, it should be + separated with a double dash ``--`` to not confuse them with the + ``container`` tool options. Plain commands with no options don't stric= tly + require the double dashes e.g.:: + + scripts/container -i docker.io/tuxmake/korg-clang make mrproper + +To run ``checkpatch.pl`` in a ``patches`` directory with a generic Perl im= age:: + + scripts/container -i perl:slim-trixie scripts/checkpatch.pl patches/* + +As an alternative to the TuxMake images, the examples below refer to +``kernel.org`` images which are based on the `kernel.org compiler toolchai= ns +`__. These aren't (yet) offic= ially +available in any public registry but users can build their own locally ins= tead +using this `experimental repository +`__ by running ``make +PREFIX=3Dkernel.org/``. + +To build just ``bzImage`` using Clang:: + + scripts/container -i kernel.org/clang -- make bzImage -j$(nproc) + +Same with GCC 15 as a particular version tag:: + + scripts/container -i kernel.org/gcc:15 -- make bzImage -j$(nproc) + +For an out-of-tree build, a trick is to bind-mount the destination directo= ry to +a relative path inside the source tree:: + + mkdir -p $HOME/tmp/my-kernel-build + mkdir -p build + sudo mount --bind $HOME/tmp/my-kernel-build build + scripts/container -i kernel.org/gcc -- make mrproper + scripts/container -i kernel.org/gcc -- make O=3Dbuild defconfig + scripts/container -i kernel.org/gcc -- make O=3Dbuild -j$(nproc) + +To run KUnit in an interactive shell and get the full output:: + + scripts/container -s -i kernel.org/gcc:kunit -- \ + tools/testing/kunit/kunit.py \ + run \ + --arch=3Dx86_64 \ + --cross_compile=3Dx86_64-linux- + +To just start an interactive shell:: + + scripts/container -si kernel.org/gcc bash + +To build the HTML documentation, which requires the ``kdocs`` image built = with +``make PREFIX=3Dkernel.org/ extra`` as it's not a compiler toolchain:: + + scripts/container -i kernel.org/kdocs make htmldocs diff --git a/Documentation/dev-tools/index.rst b/Documentation/dev-tools/in= dex.rst index 4b8425e348ab..527a0e4cf2ed 100644 --- a/Documentation/dev-tools/index.rst +++ b/Documentation/dev-tools/index.rst @@ -38,6 +38,7 @@ Documentation/process/debugging/index.rst gpio-sloppy-logic-analyzer autofdo propeller + container =20 =20 .. only:: subproject and html diff --git a/MAINTAINERS b/MAINTAINERS index affd55ff05e0..4e82dba3bd25 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -6387,6 +6387,7 @@ F: include/linux/console* CONTAINER BUILD SCRIPT M: Guillaume Tucker S: Maintained +F: Documentation/dev-tools/container.rst F: scripts/container =20 CONTEXT TRACKING --=20 2.47.3