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: a568231f4632 ("spi: mediatek: Add spi bus for Mediatek MT8173")
Cc: stable@vger.kernel.org # 4.3: ace145802350
Cc: stable@vger.kernel.org # 4.3
Cc: Leilk Liu <leilk.liu@mediatek.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://patch.msgid.link/20260410081757.503099-2-johan@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Needed for Johan's controller deregistration ordering changes.
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>
Due to additional responsibilities, Raju Rangoju will no longer be
supporting AMD SPI driver. Maintenance will be handled by Krishnamoorthi
going forward.
Cc: Krishnamoorthi M <krishnamoorthi.m@amd.com>
Signed-off-by: Raju Rangoju <Raju.Rangoju@amd.com>
Link: https://patch.msgid.link/20260406091042.4065767-1-Raju.Rangoju@amd.com
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>
Replace devm_clk_get() followed by clk_prepare_enable() with
devm_clk_get_enabled() for both "pclk" and "ref_clk". This removes
the need for explicit clock enable and disable calls, as the managed
API automatically disables the clocks on device removal or probe
failure.
Remove the now-unnecessary clk_disable_unprepare() calls from the
probe error paths and the remove callback. Simplify error handling
by jumping directly to the remove_ctlr label.
Signed-off-by: Pei Xiao <xiaopei01@kylinos.cn>
Acked-by: Michal Simek <michal.simek@amd.com>
Link: https://patch.msgid.link/24043625f89376da36feca2408f990a85be7ab36.1775555500.git.xiaopei01@kylinos.cn
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>
Pull RISC-V fixes from Paul Walmsley:
- Fix a CONFIG_SPARSEMEM crash on RV32 by avoiding early phys_to_page()
- Prevent runtime const infrastructure from being used by modules,
similar to what was done for x86
- Avoid problems when shutting down ACPI systems with IOMMUs by adding
a device dependency between IOMMU and devices that use it
- Fix a bug where the CPU pointer masking state isn't properly reset
when tagged addresses aren't enabled for a task
- Fix some incorrect register assignments, and add some missing ones,
in kgdb support code
- Fix compilation of non-kernel code that uses the ptrace uapi header
by replacing BIT() with _BITUL()
- Fix compilation of the validate_v_ptrace kselftest by working around
kselftest macro expansion issues
* tag 'riscv-for-linus-7.0-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
ACPI: RIMT: Add dependency between iommu and devices
selftests: riscv: Add braces around EXPECT_EQ()
riscv: use _BITUL macro rather than BIT() in ptrace uapi and kselftests
riscv: Reset pmm when PR_TAGGED_ADDR_ENABLE is not set
riscv: make runtime const not usable by modules
riscv: patch: Avoid early phys_to_page()
riscv: kgdb: fix several debug register assignment bugs
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>
Pull x86 fixes from Ingo Molnar:
- Fix kexec crash on KCOV-instrumented kernels (Aleksandr Nogikh)
- Fix Geode platform driver on-stack property data use-after-return
bug (Dmitry Torokhov)
* tag 'x86-urgent-2026-04-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/platform/geode: Fix on-stack property data use-after-return bug
x86/kexec: Disable KCOV instrumentation after load_segments()
EPROBE_DEFER ensures IOMMU devices are probed before the devices that
depend on them. During shutdown, however, the IOMMU may be removed
first, leading to issues. To avoid this, a device link is added
which enforces the correct removal order.
Fixes: 8f7729552582 ("ACPI: RISC-V: Add support for RIMT")
Signed-off-by: Sunil V L <sunilvl@oss.qualcomm.com>
Link: https://patch.msgid.link/20260303061605.722949-1-sunilvl@oss.qualcomm.com
Signed-off-by: Paul Walmsley <pjw@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>
Pull scheduler fixes from Ingo Molnar:
- Fix zero_vruntime tracking again (Peter Zijlstra)
- Fix avg_vruntime() usage in sched_debug (Peter Zijlstra)
* tag 'sched-urgent-2026-04-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/debug: Fix avg_vruntime() usage
sched/fair: Fix zero_vruntime tracking fix
The PROPERTY_ENTRY_GPIO macro (and by extension PROPERTY_ENTRY_REF)
creates a temporary software_node_ref_args structure on the stack
when used in a runtime assignment. This results in the property
pointing to data that is invalid once the function returns.
Fix this by ensuring the GPIO reference data is not stored on stack and
using PROPERTY_ENTRY_REF_ARRAY_LEN() to point directly to the persistent
reference data.
Fixes: 298c9babadb8 ("x86/platform/geode: switch GPIO buttons and LEDs to software properties")
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Rafael J. Wysocki <rafael@kernel.org>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Daniel Scally <djrscally@gmail.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Hans de Goede <hansg@kernel.org>
Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260329-property-gpio-fix-v2-1-3cca5ba136d8@gmail.com