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Linus Torvalds 375d5d5754 s390 updates for 7.4 merge window
- Add support for sclp-vt220 terminal resize events e.g. for QEMU
 
 - Warn if kernel command line contains non-printable EBCDIC
   characters
 
 - Improve show_code() disassembly output by using reliable markers for
   the instruction address and faulting instruction
 
 - Rework exception handling to require only a single exception table
   entry per faulting instruction: convert all inline assemblies from
   EX_TABLE to the new EX_TABLE_INSN macros. The previous exception
   handling was error prone since it usually required two EX_TABLE
   entries: one pointing at the instruction, and one pointing behind it
 
 - Disallow kprobes on instructions with exception table entries to avoid
   exception handlers decoding a breakpoint instead of the original
   instruction
 
 - Preemptible percpu ops changes:
 
   - Simplify percpu_entry() and percpu_exit() by encoding the percpu
     base, offset, and pointer registers into the lowcore marker, allowing
     percpu_exit() to update the percpu pointer on CPU migration without
     comparing the interrupted instruction
 
   - Convert this_cpu_cmpxchg(), this_cpu_xchg(), and
     this_cpu_cmpxchg128() to preemptible percpu ops; provide
     this_cpu_try_cmpxchg()
 
 - Emulate virtual timer in appldata via delayed work and remove the
   s390 specific vtimer infrastructure
 
 - Add lock contention tracepoints to rwlock slowpath
 
 - Fix incorrect return address in signal frame setup
 
 - Fix cpum_cf CPU hotplug handling
 
 - Convert various __get_free_pages() / get_zeroed_page() users to
   kmalloc() / kzalloc()
 
 - PCI:
 
   - Improve RPCIT instruction tracing
 
   - Fix double-free, use-after-free, and resource leaks in zPCI MSI
     and IRQ setup / cleanup paths
 
 - Crypto and zcrypt:
 
   - Improve reply message and length verification checks for CCA,
     EP11, and ICA messages to prevent out-of-bounds reads
 
   - Add missing array_index_nospec() for domain index uses in zcrypt to
     prevent speculative execution bypass
 
   - Fix out-of-bounds read in cca_query_crypto_facility()
 
 - Various other small fixes and improvements
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Merge tag 's390-7.4-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

Pull s390 updates from Heiko Carstens:

 - Add support for sclp-vt220 terminal resize events e.g. for QEMU

 - Warn if kernel command line contains non-printable EBCDIC characters

 - Improve show_code() disassembly output by using reliable markers for
   the instruction address and faulting instruction

 - Rework exception handling to require only a single exception table
   entry per faulting instruction: convert all inline assemblies from
   EX_TABLE to the new EX_TABLE_INSN macros. The previous exception
   handling was error prone since it usually required two EX_TABLE
   entries: one pointing at the instruction, and one pointing behind it

 - Disallow kprobes on instructions with exception table entries to
   avoid exception handlers decoding a breakpoint instead of the
   original instruction

 - Preemptible percpu ops changes:

    - Simplify percpu_entry() and percpu_exit() by encoding the percpu
      base, offset, and pointer registers into the lowcore marker,
      allowing percpu_exit() to update the percpu pointer on CPU
      migration without comparing the interrupted instruction

    - Convert this_cpu_cmpxchg(), this_cpu_xchg(), and
      this_cpu_cmpxchg128() to preemptible percpu ops; provide
      this_cpu_try_cmpxchg()

 - Emulate virtual timer in appldata via delayed work and remove the
   s390 specific vtimer infrastructure

 - Add lock contention tracepoints to rwlock slowpath

 - Fix incorrect return address in signal frame setup

 - Fix cpum_cf CPU hotplug handling

 - Convert various __get_free_pages() / get_zeroed_page() users to
   kmalloc() / kzalloc()

 - PCI:

    - Improve RPCIT instruction tracing

    - Fix double-free, use-after-free, and resource leaks in zPCI MSI
      and IRQ setup / cleanup paths

 - Crypto and zcrypt:

    - Improve reply message and length verification checks for CCA,
      EP11, and ICA messages to prevent out-of-bounds reads

    - Add missing array_index_nospec() for domain index uses in zcrypt
      to prevent speculative execution bypass

    - Fix out-of-bounds read in cca_query_crypto_facility()

 - Various other small fixes and improvements

* tag 's390-7.4-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (102 commits)
  s390/signal: Cleanup coding style
  s390/signal: Fix incorrect return address in signal frame
  s390/probes: Fix wrong mnemonic comment for clgib
  s390/probes: Add missing fixup for bctgr and bic
  s390/probes: Fix wrong opcode for cgrb fixup
  s390: Select ARCH_MEMORY_ORDER_TSO
  s390/mm: Cleanup pXXp_flush_lazy() routines
  s390/pci: Add function handle to RPCIT insn trace
  s390/pci: Use 32-bit fh outside of inline asm
  s390/pci: Adjust alignment in insn trace
  s390/sclp: Remove redundant memset after memblock_alloc_low()
  s390/entry: Save lowcore on invalid kernel stack
  s390/entry: Last breaking event vs invalid kernel stack
  s390/percpu: ImplemenHeiko Carstenst this_cpu_try_cmpxchg()
  s390/percpu: Drop unused output register from arch_this_cpu_to_op()
  s390/percpu: Drop unused output register from arch_this_cpu_add()
  s390/percpu: Use asm_inline for arch_this_cpu_add()
  s390/extable: Remove EX_TABLE macros and fallback extable search
  s390/bpf: Simplify exception table entry handling
  s390/sclp: Convert inline assembly to EX_TABLE_INSN
  ...
2026-10-20 14:28:32 -10:00
arch s390 updates for 7.4 merge window 2026-10-20 14:28:32 -10:00
block vfs-7.4-rc1.iomap 2026-10-19 18:33:02 -10:00
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 Scheduler updates: 2026-10-20 12:35:35 -10:00
drivers s390 updates for 7.4 merge window 2026-10-20 14:28:32 -10:00
fs Scheduler updates: 2026-10-20 12:35:35 -10:00
include Perf events updates: 2026-10-20 13:00:41 -10:00
init vfs-7.4-rc1.misc 2026-10-19 19:30:45 -10:00
io_uring vfs-7.4-rc1.file 2026-10-19 17:35:50 -10:00
ipc vfs-7.4-rc1.idmap 2026-10-19 17:57:49 -10:00
kernel Perf events updates: 2026-10-20 13:00:41 -10:00
lib Locking updates: 2026-10-20 12:43:05 -10:00
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 vfs-7.4-rc1.idmap 2026-10-19 17:57:49 -10:00
net vfs-7.4-rc1.shared.net-next.pidfd 2026-10-19 20:32:52 -10:00
rust rust: net: netlink: validate attribute length before casting to c_int 2026-09-29 12:28:03 +02:00
samples samples: pidfd: fix userprogs typo 2026-10-14 22:08:01 +02:00
scripts Core features: 2026-10-20 07:55:19 -10:00
security vfs-7.4-rc1.idmap 2026-10-19 17:57:49 -10:00
sound ASoC: amd: yc: disable MSI on resume 2026-10-13 14:32:22 +01:00
tools Objtool updates: 2026-10-20 12:55:04 -10:00
usr usr: Correct a spelling by changing a letter 2026-08-05 14:51:58 +02:00
virt vfs-7.4-rc1.idmap 2026-10-19 17:57:49 -10:00
.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
.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
COPYING
CREDITS vfs-7.4-rc1.bfs 2026-10-19 16:55:31 -10:00
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 Scheduler updates: 2026-10-20 12:35:35 -10:00
Makefile Linux 7.3 2026-10-18 13:14:58 -10:00
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