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 interrupts during driver unbind.
Fixes: 9ac8d17694b6 ("spi: add support for microchip fpga spi controllers")
Cc: stable@vger.kernel.org # 6.0
Cc: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://patch.msgid.link/20260409120419.388546-21-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.
Fixes: 059f545832be ("spi: add support for microchip "soft" spi controller")
Cc: stable@vger.kernel.org # 6.19
Cc: Prajna Rajendra Kumar <prajna.rajendrakumar@microchip.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://patch.msgid.link/20260409120419.388546-20-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.
Fixes: 8596124c4c1b ("spi: microchip-core-qspi: Add support for microchip fpga qspi controllers")
Cc: stable@vger.kernel.org # 6.1
Cc: Naga Sureshkumar Relli <nagasuresh.relli@microchip.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://patch.msgid.link/20260409120419.388546-19-johan@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Make sure to deregister the controller before disabling it to allow SPI
device drivers to do I/O during deregistration.
Fixes: 454fa271bc4e ("spi: Add Meson SPICC driver")
Cc: stable@vger.kernel.org # 4.13
Cc: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://patch.msgid.link/20260409120419.388546-18-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: 17f84b793c01 ("spi: lantiq-ssc: add support for Lantiq SSC SPI controller")
Cc: stable@vger.kernel.org # 4.11
Cc: Hauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://patch.msgid.link/20260409120419.388546-17-johan@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Make sure to deregister the controller before disabling and releasing
underlying resources like clocks and DMA during driver unbind.
Fixes: deba25800a12 ("spi: Add driver for IMG SPFI controller")
Cc: stable@vger.kernel.org # 3.19
Cc: Andrew Bresticker <abrestic@chromium.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://patch.msgid.link/20260409120419.388546-16-johan@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Make sure to deregister the controller before disabling runtime PM
(which can leave the controller disabled) to allow SPI device drivers to
do I/O during deregistration.
Fixes: e9abb4db8d10 ("spi: fsl-espi: add runtime PM")
Cc: stable@vger.kernel.org # 4.3
Cc: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://patch.msgid.link/20260409120419.388546-14-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: 011f23a3c2f2 ("spi/ep93xx: implemented driver for Cirrus EP93xx SPI controller")
Cc: stable@vger.kernel.org # 2.6.35
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://patch.msgid.link/20260409120419.388546-13-johan@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Make sure to deregister the controller before disabling it to allow
SPI device drivers to do I/O during deregistration.
Fixes: 3d8c0d749da3 ("spi: add support for DLN-2 USB-SPI adapter")
Cc: stable@vger.kernel.org # 4.0
Cc: Laurentiu Palcu <laurentiu.palcu@intel.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://patch.msgid.link/20260409120419.388546-12-johan@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Make sure to deregister the controller before disabling underlying
resources like clocks (via runtime pm) during driver unbind.
Fixes: 34b8c6617366 ("spi: Add Freescale/Motorola Coldfire QSPI driver")
Cc: stable@vger.kernel.org # 2.6.34
Cc: Steven King <sfking@fdwdc.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://patch.msgid.link/20260409120419.388546-11-johan@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Make sure to deregister the controller before disabling it to avoid
hanging or leaking resources associated with the queue when the queue
non-empty.
Fixes: 7347a6c7af8d ("spi: octeon: Add ThunderX driver")
Cc: stable@vger.kernel.org # 4.9
Cc: Jan Glauber <jan.glauber@gmail.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://patch.msgid.link/20260409120419.388546-10-johan@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Make sure to deregister the controller before disabling it to avoid
hanging or leaking resources associated with the queue when the queue is
non-empty.
Fixes: 22ad2d8df77d ("spi: octeon: 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/20260409120419.388546-9-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 to allow SPI drivers to
do I/O during deregistration.
Note that clocks were also disabled before the recent commit
e532e21a246d ("spi: bcm63xx-hsspi: Simplify clock handling with
devm_clk_get_enabled()").
Fixes: a38a2233f23b ("spi: bcmbca-hsspi: Add driver for newer HSSPI controller")
Cc: stable@vger.kernel.org # 6.3: deb269e0394f
Cc: stable@vger.kernel.org # 6.3
Cc: William Zhang <william.zhang@broadcom.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://patch.msgid.link/20260409120419.388546-8-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 to allow SPI drivers to
do I/O during deregistration.
Note that clocks were also disabled before the recent commit
e532e21a246d ("spi: bcm63xx-hsspi: Simplify clock handling with
devm_clk_get_enabled()").
Fixes: 7d255695804f ("spi/bcm63xx-hsspi: use devm_register_master()")
Cc: stable@vger.kernel.org # 3.14
Cc: Jonas Gorski <jonas.gorski@gmail.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://patch.msgid.link/20260409120419.388546-7-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: b42dfed83d95 ("spi: add Broadcom BCM63xx SPI controller driver")
Cc: stable@vger.kernel.org # 3.4
Cc: Florian Fainelli <florian@openwrt.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://patch.msgid.link/20260409120419.388546-6-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: 754ce4f29937 ("[PATCH] SPI: atmel_spi driver")
Cc: stable@vger.kernel.org # 2.6.21
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://patch.msgid.link/20260409120419.388546-5-johan@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>