Linux kernel source tree
Go to file
Linus Torvalds 072c0b4f0f x86 fixes. Everyone else is already in holiday mood apparently.
- Add a missing "break" to fix param parsing in the rseq selftest.
 
 - Apply runtime updates to the _current_ CPUID when userspace is setting
   CPUID, e.g. as part of vCPU hotplug, to fix a false positive and to avoid
   dropping the pending update.
 
 - Disallow toggling KVM_MEM_GUEST_MEMFD on an existing memslot, as it's not
   supported by KVM and leads to a use-after-free due to KVM failing to unbind
   the memslot from the previously-associated guest_memfd instance.
 
 - Harden against similar KVM_MEM_GUEST_MEMFD goofs, and prepare for supporting
   flags-only changes on KVM_MEM_GUEST_MEMFD memlslots, e.g. for dirty logging.
 
 - Set exit_code[63:32] to -1 (all 0xffs) when synthesizing a nested
   SVM_EXIT_ERR (a.k.a. VMEXIT_INVALID) #VMEXIT, as VMEXIT_INVALID is defined
   as -1ull (a 64-bit value).
 
 - Update SVI when activating APICv to fix a bug where a post-activation EOI
   for an in-service IRQ would effective be lost due to SVI being stale.
 
 - Immediately refresh APICv controls (if necessary) on a nested VM-Exit
   instead of deferring the update via KVM_REQ_APICV_UPDATE, as the request is
   effectively ignored because KVM thinks the vCPU already has the correct
   APICv settings.
 -----BEGIN PGP SIGNATURE-----
 
 iQFIBAABCgAyFiEE8TM4V0tmI4mGbHaCv/vSX3jHroMFAmlEQXEUHHBib256aW5p
 QHJlZGhhdC5jb20ACgkQv/vSX3jHroOscwf/ahimZsBtFTtd6yZpZ84E1O7P8g31
 aZ4p9CRcx+I0aMQKOfS98R3G1w8FtMpcX11aPWvIi4Vkx/4PVlZr+ds8cfiMV7Z+
 Hdd7k/uR4eC+KcL0XoGcmukBlHYi/8lZeijUcID+Iueo7MMlyX5G/VQ1RzBZwP++
 VFObgtzoAmlKrR5AaFeRMBnY+fiH6wMjPSwY7fI5pr4qNHrxB06wgtX5+C1Y3Poa
 7ETMrfX2XtyfG53N+1YJMGoaXqBkFaGCateMJQNOu/QQzOZhUuBCkC8muzbCTckO
 Y405j7GfpyUmhf/mdLI8BlMYrn5Mwdnvo9iJ3U5fGUN/Eh4XmPIYKy7sMg==
 =Fa0R
 -----END PGP SIGNATURE-----

Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull x86 kvm fixes from Paolo Bonzini:
 "x86 fixes.  Everyone else is already in holiday mood apparently.

   - Add a missing 'break' to fix param parsing in the rseq selftest

   - Apply runtime updates to the _current_ CPUID when userspace is
     setting CPUID, e.g. as part of vCPU hotplug, to fix a false
     positive and to avoid dropping the pending update

   - Disallow toggling KVM_MEM_GUEST_MEMFD on an existing memslot, as
     it's not supported by KVM and leads to a use-after-free due to KVM
     failing to unbind the memslot from the previously-associated
     guest_memfd instance

   - Harden against similar KVM_MEM_GUEST_MEMFD goofs, and prepare for
     supporting flags-only changes on KVM_MEM_GUEST_MEMFD memlslots,
     e.g. for dirty logging

   - Set exit_code[63:32] to -1 (all 0xffs) when synthesizing a nested
     SVM_EXIT_ERR (a.k.a. VMEXIT_INVALID) #VMEXIT, as VMEXIT_INVALID is
     defined as -1ull (a 64-bit value)

   - Update SVI when activating APICv to fix a bug where a
     post-activation EOI for an in-service IRQ would effective be lost
     due to SVI being stale

   - Immediately refresh APICv controls (if necessary) on a nested
     VM-Exit instead of deferring the update via KVM_REQ_APICV_UPDATE,
     as the request is effectively ignored because KVM thinks the vCPU
     already has the correct APICv settings"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: nVMX: Immediately refresh APICv controls as needed on nested VM-Exit
  KVM: VMX: Update SVI during runtime APICv activation
  KVM: nSVM: Set exit_code_hi to -1 when synthesizing SVM_EXIT_ERR (failed VMRUN)
  KVM: nSVM: Clear exit_code_hi in VMCB when synthesizing nested VM-Exits
  KVM: Harden and prepare for modifying existing guest_memfd memslots
  KVM: Disallow toggling KVM_MEM_GUEST_MEMFD on an existing memslot
  KVM: selftests: Add a CPUID testcase for KVM_SET_CPUID2 with runtime updates
  KVM: x86: Apply runtime updates to current CPUID during KVM_SET_CPUID{,2}
  KVM: selftests: Add missing "break" in rseq_test's param parsing
2025-12-20 11:31:37 -08:00
arch x86 fixes. Everyone else is already in holiday mood apparently. 2025-12-20 11:31:37 -08:00
block block-6.19-20251218 2025-12-20 09:48:56 -08:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto Networking changes for 6.19. 2025-12-03 17:24:33 -08:00
Documentation block-6.19-20251218 2025-12-20 09:48:56 -08:00
drivers IOMMU Fixes for Linux v6.19-rc1 2025-12-20 11:18:32 -08:00
fs 3 smb3 client fixes 2025-12-19 07:50:20 +12:00
include block-6.19-20251218 2025-12-20 09:48:56 -08:00
init Significant patch series in this pull request: 2025-12-06 14:01:20 -08:00
io_uring io_uring-6.19-20251218 2025-12-20 09:38:56 -08:00
ipc Significant patch series in this pull request: 2025-12-06 14:01:20 -08:00
kernel tracing fixes for v6.19: 2025-12-19 09:30:55 +12:00
lib lib/crypto: riscv: Add poly1305-core.S to .gitignore 2025-12-14 10:18:22 -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
mm slab fix for 6.19-rc2 2025-12-20 11:24:42 -08:00
net Including fixes from netfilter and CAN. 2025-12-19 07:55:35 +12:00
rust USB/Thunderbolt changes for 6.19-rc1 2025-12-06 18:42:12 -08:00
samples USB/Thunderbolt changes for 6.19-rc1 2025-12-06 18:42:12 -08:00
scripts There are no significant series in this small merge. Please see the 2025-12-13 20:55:12 +12:00
security Trivial optimization. 2025-12-14 15:21:02 +12:00
sound soundwire updates for 6.19 2025-12-13 16:26:55 +12:00
tools x86 fixes. Everyone else is already in holiday mood apparently. 2025-12-20 11:31:37 -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 Significant patch series in this pull request: 2025-12-06 14:01:20 -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 Including fixes from netfilter and CAN. 2025-12-19 07:55:35 +12:00
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 tracing fixes for v6.19: 2025-12-19 09:30:55 +12:00
Makefile Linux 6.19-rc1 2025-12-14 16:05:07 +12:00
README README: restructure with role-based documentation and guidelines 2025-11-29 08:40:33 -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


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