Linux kernel source tree
 
 
 
 
 
 
Go to file
Linus Torvalds ceaeaf66a2 Two perf events fixes:
- Fix mmap_count warning & bug when creating a group member event
    with the PERF_FLAG_FD_OUTPUT flag.
 
  - Disable the sample period == 1 branch events BTS optimization
    on guests, because BTS is not virtualized.
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
 -----BEGIN PGP SIGNATURE-----
 
 iQJFBAABCgAvFiEEBpT5eoXrXCwVQwEKEnMQ0APhK1gFAml0kF8RHG1pbmdvQGtl
 cm5lbC5vcmcACgkQEnMQ0APhK1icZxAAhsYBY0uB3OzAgJYRIVlw/vzF7ubHh8+r
 PhQ+azap/uSk/dS8IXZ0FrP/vq9kgqEFpsYwWbB1EFRxB24nd8AAYarASyc22Dhb
 Qe6tKh4hzlDC9Cw0vJ111PgKJLiPDrmkxzS4C2HkPwYwriNql81hQjLW5nF6dHwg
 i8aP7+/uNB2h/xnPIRgkUFSUzBacRz1Snqgi/vSHmwEhk1GFI48rXoYywM9ItAnR
 CGN7tGxJ45YwDYeknZf9Ngsd3q+/eh38ihPfMEKoulf4oFvhIsiG4rJ1Vee0V9fD
 aD1NhukULtjw3lkKnMM75W+Jdb7fHDTOuxzUov9WpyIOIUTMqRkbvaKHgJzSD2SK
 01TbP3kQixhGhiRXx78GDQwYGjX8JQxngbqyJvL708GNvxbcKYrLhqtr5Ho00pWH
 ERxx/ajoDXB7Neo7XPhgYRHk/lrlnZsK1LoidhMzN1UX6C12VnhPcD+zUSqRxz5w
 yFuJp0+7wF+G74FpO7kv8jv5KDB/lery5mdzWu0kqAKMfYWdw5eGoaI6T48DVoBy
 IwNYU8bxDBRPzu64XudDE4xBuTuy4HpJmbvOUkxMUkBGMTZ+nysqHu8D7cJJqYtL
 2xYJOpR+P4Se9fRyR9xo5vtTZy27TQqTp+AjA5RlIoVOJhYK5T9mAFCJaEhdupbM
 2IA4xdYhbb8=
 =lNSW
 -----END PGP SIGNATURE-----

Merge tag 'perf-urgent-2026-01-24' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull perf events fixes from Ingo Molnar:

 - Fix mmap_count warning & bug when creating a group member event
   with the PERF_FLAG_FD_OUTPUT flag

 - Disable the sample period == 1 branch events BTS optimization
   on guests, because BTS is not virtualized

* tag 'perf-urgent-2026-01-24' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86/intel: Do not enable BTS for guests
  perf: Fix refcount warning on event->mmap_count increment
2026-01-24 09:24:17 -08:00
Documentation platform-drivers-x86 for v6.19-3 2026-01-23 13:16:26 -08:00
LICENSES LICENSES: Add modern form of the LGPL-2.1 tags to the usage guide section 2025-10-22 07:58:19 +02:00
arch Two perf events fixes: 2026-01-24 09:24:17 -08:00
block block-6.19-20260122 2026-01-23 12:53:56 -08:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto crypto: authencesn - reject too-short AAD (assoclen<8) to match ESP/ESN spec 2026-01-20 14:38:48 +08:00
drivers Two irqchip driver fixes: 2026-01-24 09:15:25 -08:00
fs three ksmbd server fixes 2026-01-23 13:40:55 -08:00
include block-6.19-20260122 2026-01-23 12:53:56 -08:00
init Significant patch series in this pull request: 2025-12-06 14:01:20 -08:00
io_uring io_uring-6.19-20260122 2026-01-23 12:51:00 -08:00
ipc Significant patch series in this pull request: 2025-12-06 14:01:20 -08:00
kernel Two perf events fixes: 2026-01-24 09:24:17 -08:00
lib lib/buildid: use __kernel_read() for sleepable context 2026-01-14 22:16:21 -08:00
mm slab fix for 6.19-rc7 2026-01-21 09:19:15 -08:00
net net/sched: act_ife: avoid possible NULL deref 2026-01-22 08:01:44 -08:00
rust rust: bitops: fix missing _find_* functions on 32-bit ARM 2026-01-13 22:16:39 -05:00
samples samples/ftrace: Adjust LoongArch register restore order in direct calls 2025-12-31 15:19:25 +08:00
scripts kconfig: fix static linking of nconf 2026-01-14 14:23:20 +01:00
security Landlock fix for v6.19-rc6 2026-01-18 15:15:47 -08:00
sound ALSA: hda/realtek: ALC269 fixup for Lenovo Yoga Book 9i 13IRU8 audio 2026-01-22 13:33:41 +01:00
tools Fix objtool build error in non-standard static library build 2026-01-24 09:22:09 -08:00
usr initramfs: add gen_init_cpio to hostprogs unconditionally 2025-11-26 21:55:40 +01:00
virt KVM fixes for 6.19-rc1 2025-12-18 18:38:45 +01:00
.clang-format s390/pci: Fix cyclic dead-lock in zpci_zdev_put() and zpci_scan_devices() 2025-12-14 11:03:58 +01:00
.clippy.toml rust: clean Rust 1.88.0's warning about `clippy::disallowed_macros` configuration 2025-05-07 00:11:47 +02:00
.cocciconfig
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore MAINTAINERS: remove Alyssa Rosenzweig 2025-09-18 21:17:31 +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 soc: fixes for 6.19, part 2 2026-01-21 09:34:45 -08:00
.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 nfc: MAINTAINERS: Orphan the NFC and look for new maintainers 2026-01-20 16:05:38 -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 Including fixes from CAN and wireless. 2026-01-22 09:32:11 -08:00
Makefile Linux 6.19-rc6 2026-01-18 15:42:45 -08:00
README README: restructure with role-based documentation and guidelines 2025-11-29 08:40:33 -07:00

README

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


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



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