Linux kernel ============ The Linux kernel is the core of any Linux operating system. It manages hardware, system resources, and provides the fundamental services for all other software. Quick Start ----------- * Report a bug: See Documentation/admin-guide/reporting-issues.rst * Get the latest kernel: https://kernel.org * Build the kernel: See Documentation/admin-guide/quickly-build-trimmed-linux.rst * Join the community: https://lore.kernel.org/ Essential Documentation ----------------------- All users should be familiar with: * Building requirements: Documentation/process/changes.rst * Code of Conduct: Documentation/process/code-of-conduct.rst * License: See COPYING Documentation can be built with make htmldocs or viewed online at: https://www.kernel.org/doc/html/latest/ Who Are You? ============ Find your role below: * New Kernel Developer - Getting started with kernel development * Academic Researcher - Studying kernel internals and architecture * Security Expert - Hardening and vulnerability analysis * Backport/Maintenance Engineer - Maintaining stable kernels * System Administrator - Configuring and troubleshooting * Maintainer - Leading subsystems and reviewing patches * Hardware Vendor - Writing drivers for new hardware * Distribution Maintainer - Packaging kernels for distros * AI Coding Assistant - LLMs and AI-powered development tools For Specific Users ================== New Kernel Developer -------------------- Welcome! Start your kernel development journey here: * Getting Started: Documentation/process/development-process.rst * Your First Patch: Documentation/process/submitting-patches.rst * Coding Style: Documentation/process/coding-style.rst * Build System: Documentation/kbuild/index.rst * Development Tools: Documentation/dev-tools/index.rst * Kernel Hacking Guide: Documentation/kernel-hacking/hacking.rst * Core APIs: Documentation/core-api/index.rst Academic Researcher ------------------- Explore the kernel's architecture and internals: * Researcher Guidelines: Documentation/process/researcher-guidelines.rst * Memory Management: Documentation/mm/index.rst * Scheduler: Documentation/scheduler/index.rst * Networking Stack: Documentation/networking/index.rst * Filesystems: Documentation/filesystems/index.rst * RCU (Read-Copy Update): Documentation/RCU/index.rst * Locking Primitives: Documentation/locking/index.rst * Power Management: Documentation/power/index.rst Security Expert --------------- Security documentation and hardening guides: * Security Documentation: Documentation/security/index.rst * LSM Development: Documentation/security/lsm-development.rst * Self Protection: Documentation/security/self-protection.rst * Reporting Vulnerabilities: Documentation/process/security-bugs.rst * CVE Procedures: Documentation/process/cve.rst * Embargoed Hardware Issues: Documentation/process/embargoed-hardware-issues.rst * Security Features: Documentation/userspace-api/seccomp_filter.rst Backport/Maintenance Engineer ----------------------------- Maintain and stabilize kernel versions: * Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst * Backporting Guide: Documentation/process/backporting.rst * Applying Patches: Documentation/process/applying-patches.rst * Subsystem Profile: Documentation/maintainer/maintainer-entry-profile.rst * Git for Maintainers: Documentation/maintainer/configure-git.rst System Administrator -------------------- Configure, tune, and troubleshoot Linux systems: * Admin Guide: Documentation/admin-guide/index.rst * Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst * Sysctl Tuning: Documentation/admin-guide/sysctl/index.rst * Tracing/Debugging: Documentation/trace/index.rst * Performance Security: Documentation/admin-guide/perf-security.rst * Hardware Monitoring: Documentation/hwmon/index.rst Maintainer ---------- Lead kernel subsystems and manage contributions: * Maintainer Handbook: Documentation/maintainer/index.rst * Pull Requests: Documentation/maintainer/pull-requests.rst * Managing Patches: Documentation/maintainer/modifying-patches.rst * Rebasing and Merging: Documentation/maintainer/rebasing-and-merging.rst * Development Process: Documentation/process/maintainer-handbooks.rst * Maintainer Entry Profile: Documentation/maintainer/maintainer-entry-profile.rst * Git Configuration: Documentation/maintainer/configure-git.rst Hardware Vendor --------------- Write drivers and support new hardware: * Driver API Guide: Documentation/driver-api/index.rst * Driver Model: Documentation/driver-api/driver-model/driver.rst * Device Drivers: Documentation/driver-api/infrastructure.rst * Bus Types: Documentation/driver-api/driver-model/bus.rst * Device Tree Bindings: Documentation/devicetree/bindings/ * Power Management: Documentation/driver-api/pm/index.rst * DMA API: Documentation/core-api/dma-api.rst Distribution Maintainer ----------------------- Package and distribute the kernel: * Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst * ABI Documentation: Documentation/ABI/README * Kernel Configuration: Documentation/kbuild/kconfig.rst * Module Signing: Documentation/admin-guide/module-signing.rst * Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst * Tainted Kernels: Documentation/admin-guide/tainted-kernels.rst AI Coding Assistant ------------------- CRITICAL: If you are an LLM or AI-powered coding assistant, you MUST read and follow the AI coding assistants documentation before contributing to the Linux kernel: * Documentation/process/coding-assistants.rst This documentation contains essential requirements about licensing, attribution, and the Developer Certificate of Origin that all AI tools must comply with. Communication and Support ========================= * Mailing Lists: https://lore.kernel.org/ * IRC: #kernelnewbies on irc.oftc.net * Bugzilla: https://bugzilla.kernel.org/ * MAINTAINERS file: Lists subsystem maintainers and mailing lists * Email Clients: Documentation/process/email-clients.rst
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Make sure to deregister the controller before disabling underlying
resources like clocks during driver unbind.
Fixes: dfe11a11d523 ("spi: Add support for Zynq Ultrascale+ MPSoC GQSPI controller")
Cc: stable@vger.kernel.org # 4.2: 64640f6c972e
Cc: stable@vger.kernel.org # 4.2
Cc: Ranjit Waghmode <ranjit.waghmode@xilinx.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://patch.msgid.link/20260410081757.503099-26-johan@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Make sure to deregister the controller before releasing underlying
resources like DMA during driver unbind.
Note that clocks were also disabled before the recent commit
fdca270f8f87 ("spi: uniphier: Simplify clock handling with
devm_clk_get_enabled()").
Fixes: 5ba155a4d4cc ("spi: add SPI controller driver for UniPhier SoC")
Cc: stable@vger.kernel.org # 4.19
Cc: Keiji Hayashibara <hayashibara.keiji@socionext.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://patch.msgid.link/20260410081757.503099-25-johan@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Make sure to deregister the controller before disabling underlying
resources like clocks during driver unbind.
Note that the controller is suspended before disabling and releasing
resources since commit 3ac066e2227c ("spi: spi-ti-qspi: Suspend the
queue before removing the device") which avoids issues like unclocked
accesses but prevents SPI device drivers from doing I/O during
deregistration.
Fixes: 3b3a80019ff1 ("spi: ti-qspi: one only one interrupt handler")
Cc: stable@vger.kernel.org # 3.13
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://patch.msgid.link/20260410081757.503099-24-johan@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Make sure to deregister the controller before disabling underlying
resources like clocks during driver unbind.
Fixes: f12f7318c44a ("spi: tegra20-sflash: use devm_spi_register_master()")
Cc: stable@vger.kernel.org # 3.13
Cc: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://patch.msgid.link/20260410081757.503099-23-johan@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Make sure to deregister the controller before disabling underlying
resources like clocks during driver unbind.
Fixes: 5c8096439600 ("spi: tegra114: use devm_spi_register_master()")
Cc: stable@vger.kernel.org # 3.13
Cc: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://patch.msgid.link/20260410081757.503099-22-johan@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Make sure to deregister the controller before disabling underlying
resources like clocks during driver unbind.
Fixes: b0823ee35cf9 ("spi: Add spi driver for Socionext SynQuacer platform")
Cc: stable@vger.kernel.org # 5.3
Cc: Masahisa Kojima <masahisa.kojima@linaro.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://patch.msgid.link/20260410081757.503099-21-johan@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Make sure to deregister the controller before disabling underlying
resources like clocks during driver unbind.
Fixes: 3558fe900e8a ("spi: sunxi: Add Allwinner A31 SPI controller driver")
Cc: stable@vger.kernel.org # 3.15
Cc: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://patch.msgid.link/20260410081757.503099-20-johan@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Make sure to deregister the controller before disabling underlying
resources like clocks during driver unbind.
Fixes: b5f6517948cc ("spi: sunxi: Add Allwinner A10 SPI controller driver")
Cc: stable@vger.kernel.org # 3.15
Cc: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://patch.msgid.link/20260410081757.503099-19-johan@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Make sure to deregister the controller before disabling underlying
resources like clocks during driver unbind.
Fixes: 9e862375c542 ("spi: Add new driver for STMicroelectronics' SPI Controller")
Cc: stable@vger.kernel.org # 4.0
Cc: Lee Jones <lee@kernel.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://patch.msgid.link/20260410081757.503099-18-johan@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Make sure to deregister the controller before disabling underlying
resources like clocks during driver unbind.
Note that the controller is suspended before disabling and releasing
resources since commit de082d866cce ("spi: sprd: Add the SPI irq
function for the SPI DMA mode") which avoids issues like unclocked
accesses but prevents SPI device drivers from doing I/O during
deregistration.
Fixes: e7d973a31c24 ("spi: sprd: Add SPI driver for Spreadtrum SC9860")
Cc: stable@vger.kernel.org # 4.20
Cc: Lanqing Liu <lanqing.liu@spreadtrum.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://patch.msgid.link/20260410081757.503099-17-johan@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Make sure to deregister the controller before disabling underlying
resources like clocks (by disabling runtime PM) during driver unbind.
Fixes: 805be7ddf367 ("spi: mediatek: add spi slave for Mediatek MT2712")
Cc: stable@vger.kernel.org # 4.20
Cc: Leilk Liu <leilk.liu@mediatek.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://patch.msgid.link/20260410081757.503099-16-johan@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Make sure to deregister the controller before disabling underlying
resources like interrupts during driver unbind.
Note that clocks were also disabled before the recent commit
140039c23aca ("spi: sifive: Simplify clock handling with
devm_clk_get_enabled()").
Fixes: 484a9a68d669 ("spi: sifive: Add driver for the SiFive SPI controller")
Cc: stable@vger.kernel.org # 5.1
Cc: Yash Shah <yash.shah@sifive.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://patch.msgid.link/20260410081757.503099-15-johan@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Make sure to deregister the controller before releasing underlying
resources like DMA during driver unbind.
Fixes: 1bd6363bc0c6 ("spi: sh-msiof: Use core message handling instead of spi-bitbang")
Cc: stable@vger.kernel.org # 3.15
Cc: Geert Uytterhoeven <geert+renesas@linux-m68k.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://patch.msgid.link/20260410081757.503099-14-johan@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Make sure to deregister the controller before releasing underlying
resources like clocks during driver unbind.
Fixes: 49e599b8595f ("spi: sh-hspi: control spi clock more correctly")
Cc: stable@vger.kernel.org # 3.4
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://patch.msgid.link/20260410081757.503099-13-johan@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Make sure to deregister the controller before releasing underlying
resources like DMA during driver unbind.
Fixes: 91800f0e9005 ("spi/s3c64xx: Use managed registration")
Cc: stable@vger.kernel.org # 3.13: 76fbad410c0f
Cc: stable@vger.kernel.org # 3.13
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://patch.msgid.link/20260410081757.503099-12-johan@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Make sure to deregister the controller before releasing underlying
resources like DMA during driver unbind.
Fixes: 9e03d05eee4c ("spi: rcar: Use devm_spi_register_master()")
Cc: stable@vger.kernel.org # 3.14
Cc: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://patch.msgid.link/20260410081757.503099-11-johan@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>