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Linus Torvalds 28483203f7 RCU changes for v7.1
NOCB CPU management:
 
 - Consolidate rcu_nocb_cpu_offload() and rcu_nocb_cpu_deoffload() to reduce
   code duplication.
 - Extract nocb_bypass_needs_flush() helper to reduce duplication in NOCB
   bypass path.
 
 rcutorture/torture infrastructure:
 
 - Add NOCB01 config for RCU_LAZY torture testing.
 - Add NOCB02 config for NOCB poll mode testing.
 - Add TRIVIAL-PREEMPT config for textbook-style preemptible RCU torture.
 - Test call_srcu() with preemption both disabled and enabled.
 - Remove kvm-check-branches.sh in favor of kvm-series.sh.
 - Make hangs more visible in torture.sh output.
 - Add informative message for tests without a recheck file.
 - Fix numeric test comparison in srcu_lockdep.sh.
 - Use torture_shutdown_init() in refscale and rcuscale instead of open-coded
   shutdown functions.
 - Fix modulo-zero error in torture_hrtimeout_ns().
 
 SRCU:
 
 - Fix SRCU read flavor macro comments.
 - Fix s/they disables/they disable/ typo in srcu_read_unlock_fast().
 
 RCU Tasks:
 
 - Document that RCU Tasks Trace grace periods now imply RCU grace periods.
 - Remove unnecessary smp_store_release() in cblist_init_generic().
 
 RCU stall:
 
 - Add BOOTPARAM_RCU_STALL_PANIC Kconfig option to allow triggering a kernel
   panic on RCU stall via kernel boot parameter.
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Merge tag 'rcu.2026.03.31a' of git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux

Pull RCU updates from Joel Fernandes:
 "NOCB CPU management:

   - Consolidate rcu_nocb_cpu_offload() and rcu_nocb_cpu_deoffload() to
     reduce code duplication

   - Extract nocb_bypass_needs_flush() helper to reduce duplication in
     NOCB bypass path

  rcutorture/torture infrastructure:

   - Add NOCB01 config for RCU_LAZY torture testing

   - Add NOCB02 config for NOCB poll mode testing

   - Add TRIVIAL-PREEMPT config for textbook-style preemptible RCU
     torture

   - Test call_srcu() with preemption both disabled and enabled

   - Remove kvm-check-branches.sh in favor of kvm-series.sh

   - Make hangs more visible in torture.sh output

   - Add informative message for tests without a recheck file

   - Fix numeric test comparison in srcu_lockdep.sh

   - Use torture_shutdown_init() in refscale and rcuscale instead of
     open-coded shutdown functions

   - Fix modulo-zero error in torture_hrtimeout_ns().

  SRCU:

   - Fix SRCU read flavor macro comments

   - Fix s/they disables/they disable/ typo in srcu_read_unlock_fast()

  RCU Tasks:

   - Document that RCU Tasks Trace grace periods now imply RCU grace
     periods

   - Remove unnecessary smp_store_release() in cblist_init_generic()"

* tag 'rcu.2026.03.31a' of git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux:
  rcutorture: Test call_srcu() with preemption disabled and not
  rcu: Add BOOTPARAM_RCU_STALL_PANIC Kconfig option
  torture: Avoid modulo-zero error in torture_hrtimeout_ns()
  rcu/nocb: Extract nocb_bypass_needs_flush() to reduce duplication
  rcu/nocb: Consolidate rcu_nocb_cpu_offload/deoffload functions
  rcu-tasks: Remove unnecessary smp_store_release() in cblist_init_generic()
  rcutorture: Add NOCB02 config for nocb poll mode testing
  rcutorture: Add NOCB01 config for RCU_LAZY torture testing
  rcu-tasks: Document that RCU Tasks Trace grace periods now imply RCU grace periods
  srcu: Fix s/they disables/they disable/ typo in srcu_read_unlock_fast()
  srcu: Fix SRCU read flavor macro comments
  rcuscale: Ditch rcu_scale_shutdown in favor of torture_shutdown_init()
  refscale: Ditch ref_scale_shutdown in favor of torture_shutdown_init()
  rcutorture: Fix numeric "test" comparison in srcu_lockdep.sh
  torture: Print informative message for test without recheck file
  torture: Make hangs more visible in torture.sh output
  kvm-check-branches.sh: Remove in favor of kvm-series.sh
  rcutorture: Add a textbook-style trivial preemptible RCU
2026-04-13 09:36:45 -07:00
arch Merge branch 'nocache-cleanup' 2026-04-13 08:39:51 -07:00
block block-7.0-20260305 2026-03-06 08:36:18 -08:00
certs Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
crypto This push contains the following changes: 2026-04-12 08:11:02 -07:00
Documentation RCU changes for v7.1 2026-04-13 09:36:45 -07:00
drivers Merge branch 'nocache-cleanup' 2026-04-13 08:39:51 -07:00
fs vfs-7.0-rc8.fixes 2026-04-10 08:40:49 -07:00
include RCU changes for v7.1 2026-04-13 09:36:45 -07:00
init hardening fixes for v7.0-rc6 2026-03-25 14:47:18 -07:00
io_uring io_uring-7.0-20260403 2026-04-03 11:58:04 -07:00
ipc Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
kernel RCU changes for v7.1 2026-04-13 09:36:45 -07:00
lib Merge branch 'nocache-cleanup' 2026-04-13 08:39:51 -07:00
LICENSES LICENSES: Add modern form of the LGPL-2.1 tags to the usage guide section 2025-10-22 07:58:19 +02:00
mm 8 hotfixes. All are cc:stable and 7 are for MM. 2026-04-07 10:24:44 -07:00
net vfs-7.0-rc8.fixes 2026-04-10 08:40:49 -07:00
rust rust: regulator: do not assume that regulator_get() returns non-null 2026-03-24 13:08:21 +00:00
samples Landlock fix for v7.0-rc6 2026-03-26 12:03:37 -07:00
scripts modpost: Declare extra_warn with unused attribute 2026-03-30 07:45:34 +02:00
security proc: make PROC_MEM_FORCE_PTRACE the Kconfig default 2026-04-13 09:12:37 -07:00
sound ASoC: Fixes for v7.0 2026-04-09 07:00:53 +02:00
tools RCU changes for v7.1 2026-04-13 09:36:45 -07:00
usr kbuild: uapi: drop dependency on CC_CAN_LINK 2026-01-16 15:02:11 -07:00
virt KVM generic changes for 7.0 2026-03-11 18:01:55 +01:00
.clang-format Devicetree updates for v7.0: 2026-02-11 18:27:08 -08:00
.clippy.toml rust: clean Rust 1.88.0's warning about clippy::disallowed_macros configuration 2025-05-07 00:11:47 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.editorconfig editorconfig: add rst extension 2026-01-26 19:07:09 -08:00
.get_maintainer.ignore .get_maintainer.ignore: add myself 2026-04-02 16:48:25 +02:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore rust: kbuild: add proc macro library support 2025-11-24 17:15:36 +01:00
.mailmap MAINTAINERS, mailmap: Change Ulf Hansson's email 2026-04-07 14:17:48 +02:00
.pylintrc docs: Move the python libraries to tools/lib/python 2025-11-18 09:22:40 -07:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: remove Thomas Falcon from IBM ibmvnic 2026-03-05 07:35:45 -08:00
Kbuild sched: Make migrate_{en,dis}able() inline 2025-09-25 09:57:16 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS spi: Fixes for v7.0 2026-04-11 12:49:21 -07:00
Makefile Linux 7.0 2026-04-12 13:48:06 -07:00
README docs: add AI Coding Assistants documentation 2026-01-06 14:55:06 -07:00

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