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Linus Torvalds 03741bcea0 More x86 fixes:
- Fix a WARN if the SS bit is set in #NPF exit codes; the AMD manual
   is unclear about whether it can be set when the guest uses CET but the
   SupervisorShadowStackEn feature (which KVM does not use) is disabled.
   However, Hyper-V has started using CET now that KVM supports GMET
   (it wants the two feature in pairs), and that dissolves all the doubts:
   the SS bit *is* reported and not clearing it causes a WARN and/or a
   UBSAN splat.
 
 - If creating a vCPU ultimately fails, clear its entry in the AVIC Physical ID
   table used by hardware to perform IPI Virtualization and delivered posted
   IRQs.  I.e. plug the same use-after-free hole related to IPI virtualization
   and posted IRQs that was fixed for APICv by commit b41f2ca6c0 ("KVM: VMX:
   Fix stale PID-pointer table entry left after vCPU free").
 
 - Use set_page_dirty_lock() instead of set_page_dirty() when marking a page
   dirty after writing back SNP firmware's desired CPUID state to userspace.
   Using set_page_dirty() is unsafe if the page/folio isn't locked (as pointed
   out by its function comment's big DANGER warning, which no one reads given
   the number of bugs of this exact nature).
 
 - When checking for an MMIO generation match, use the memslots for the current
   vCPU context (non-SMM vs. SMM), as a misbehaving guest can coerce KVM into
   incorrectly identifying a write as MMIO in order to bypass KVM's
   write-tracking.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull kvm fixes from Paolo Bonzini:
 "More x86 fixes:

   - Fix a WARN if the SS bit is set in #NPF exit codes.

     The AMD manual is unclear about whether it can be set when the
     guest uses CET but the SupervisorShadowStackEn feature (which KVM
     does not use) is disabled. However, Hyper-V has started using CET
     now that KVM supports GMET (it wants the two feature in pairs), and
     that dissolves all the doubts: the SS bit *is* reported and not
     clearing it causes a WARN and/or a UBSAN splat.

   - If creating a vCPU ultimately fails, clear its entry in the AVIC
     Physical ID table used by hardware to perform IPI Virtualization
     and delivered posted IRQs.

     I.e. plug the same use-after-free hole related to IPI
     virtualization and posted IRQs that was fixed for APICv by commit
     b41f2ca6c0 ("KVM: VMX: Fix stale PID-pointer table entry left
     after vCPU free").

   - Use set_page_dirty_lock() instead of set_page_dirty() when marking
     a page dirty after writing back SNP firmware's desired CPUID state
     to userspace.

     Using set_page_dirty() is unsafe if the page/folio isn't locked (as
     pointed out by its function comment's big DANGER warning, which no
     one reads given the number of bugs of this exact nature).

   - When checking for an MMIO generation match, use the memslots for
     the current vCPU context (non-SMM vs. SMM), as a misbehaving guest
     can coerce KVM into incorrectly identifying a write as MMIO in
     order to bypass KVM's write-tracking"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: x86/mmu: Cope with the SS bit being set in #NPF exit codes
  KVM: x86: Use active memslots for the per-vCPU MMIO cache
  KVM: SEV: Fix page dirtying in sev_gmem_post_populate()
  KVM: SVM: Clear AVIC Physical ID table entry if vCPU creation fails
  KVM: SVM: Use "is AVIC-addressable" helper to sanity check load()/put()
  KVM: SVM: Add paranoid helper for checking if vCPU is AVIC-addressable
History 2026-10-13 16:41:23 -07:00
arch More x86 fixes: 2026-10-13 16:41:23 -07:00
block block-7.3-20261002 2026-10-02 12:25:40 -07:00
certs treewide: fix indentation and whitespace in Kconfig files 2026-05-28 21:24:42 -07:00
crypto crypto: aes - Fix undesired override of some optimized AES modes 2026-09-30 08:38:06 -07:00
Documentation spi: Fixes for v7.3 2026-10-11 11:33:26 -07:00
drivers spi: Fixes for v7.3 2026-10-11 11:33:26 -07:00
fs xfs: fix exchange-range-to-eof file size exchange 2026-10-11 08:23:43 +02:00
include block-7.3-20261010 2026-10-11 09:00:33 -07:00
init Random number generator fixes for Linux 7.3-rc6. 2026-10-02 11:28:45 -07:00
io_uring io_uring-7.3-20261010 2026-10-11 08:53:11 -07:00
ipc mm.git review status for master..mm-nonmm-stable 2026-08-23 08:07:11 -07:00
kernel dma-mapping fixes for Linux 7.3 2026-10-10 00:49:55 +02:00
lib lib/dim: add KUnit test for dim_calc_stats() 2026-10-02 07:52:31 +01:00
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 mm: don't schedule deferred kernel page table freeing while booting 2026-10-06 16:44:18 -07:00
net vsock: Fix memory leak in vmci_transport_recv_dgram_cb() 2026-10-08 11:46:13 -07:00
rust rust: net: netlink: validate attribute length before casting to c_int 2026-09-29 12:28:03 +02:00
samples rust: samples: add missing newlines in rust_print_main 2026-09-01 02:20:22 +02:00
scripts hid-for-linus-2026092202 2026-09-22 10:30:17 -07:00
security Landlock fix for v7.3-rc7 2026-10-11 11:49:08 -07:00
sound ASoC: Fixes for v7.3 2026-10-08 10:49:55 +02:00
tools vfs-7.3-rc7.fixes 2026-10-09 23:37:44 +02:00
usr usr: Correct a spelling by changing a letter 2026-08-05 14:51:58 +02:00
virt KVM: WARN if vCPU creation is in-progress when locking all vCPUs 2026-09-26 00:49:49 -04:00
.clang-format drm/bridge: rename drm_for_each_bridge_in_chain_scoped() to drm_for_each_bridge_in_chain() 2026-07-14 17:55:51 +02:00
.clippy.toml rust: bump Clippy's MSRV and clean incompatible_msrv allows 2026-04-07 09:51:39 +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 2026-09-07 10:01:33 +02:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore SPDX patches for 7.2-rc1 2026-06-22 12:06:22 -07:00
.mailmap 7 hotfixes. 4 are cc:stable. 2026-10-08 12:35:20 +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 Driver core fixes for 7.3-rc2 2026-09-05 11:59:05 -07:00
Kbuild checksyscalls: move instance functionality into generic code 2026-04-05 09:21:32 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS Mark the ext4 data=journal feature as being deprecated and will be 2026-10-08 17:37:49 +02:00
Makefile Linux 7.3-rc7 2026-10-11 20:04:55 -07:00
README README: remove out of place emdashes 2026-07-15 10:51:29 -06:00

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