Linux kernel source tree
Go to file
Linus Torvalds 6439079365 Probes updates for v7.3:
- probes: Advanced BTF typecasting and variable fetch enhancements
   . Typecast support across probe events: Extended BTF typecasting syntax
     (e.g., (STRUCT)PARAM->MEMBER) to kprobes, uprobes, and fprobes on
     function entry and return.
   . Nested typecasts: Added support for chaining and nesting typecasts up
     to 3 levels, including casting registers and stack variables.
   . Field specifier option: Added (STRUCT,FIELD) syntax to emulate
     container_of(), allowing retrieval of parent structures from member
     pointers.
   . $current variable support: Introduced $current special variable to
     access the running task_struct via BTF dereferencing.
   . Per-CPU variable access: Added this_cpu_read() and this_cpu_ptr()
     fetcharg methods to trace CPU-local data safely.
   . Fetcharg bytecode dumper: Added CONFIG_PROBE_EVENTS_DUMP_FETCHARG to
     dump the compiled fetcharg bytecode instructions as comments in
     dynamic_events.
   . Extended symbol name handling: Removed the MAX_COMMON_HEAD_LEN limit
     and extended MAX_ARGSTR_LEN to 256 bytes, enabling probing of long
     symbols, mangled Rust symbols and complex BTF expressions.
   . eprobe variable syntax: Allowed eprobes to reference event fields
     directly without requiring a '$' prefix.
   . Cleanup unused parameters, redundant codes, duplicate macros and
     pointer arithmetic.
   . Use a ternary operator for simplifying fetch_type_from_btf_type().
 
 - bootconfig / boottime-trace: Expanded dynamic probe support
   . Added boot-time tracing configuration support for event probes
     (eprobes), function probes (fprobes), and tracepoint probes
     (tprobes).
   . ftrace2bootconfig: Allowed comment lines ('#') in dynamic_events file.
 
 - fprobe / kprobe: Optimization, robustness, and cleanups
   . fprobe: Simplified fprobe_remove_ips() by reusing graph and ftrace
     helpers.
   . fprobe: Removed __packed attribute from struct __fprobe_header to avoid
     unaligned memory access penalties on RISC architectures.
   . kprobe & fprobe: Removed redundant memset() calls in perf event probe
     handlers.
   . kprobes: Replaced legacy __ASSEMBLY__ with __ASSEMBLER__ in header
     files.
 
 - selftests & refactoring:
   . Refactored parse_probe_arg() and parse_probe_vars(), and eliminated
     recursion in probe argument parsing to protect kernel stack depth.
   . Added selftests for BTF typecasts and module probing without module
     prefixes.
   . Forced LC_ALL=C in ftracetest to prevent test failures on localized
     systems.
   . Refactored btf_type_skip_modifiers() to remove ignored id parameter.
   . Sorted ERRORS list in trace_probe.h alphabetically.
   . Fixed typo in fprobe docs, and trace_fprobe function name.
   . Renamed FETCH_OP_DATA to FETCH_OP_IMMSTR.
   . Made file offset error message probe-agnostic.
 -----BEGIN PGP SIGNATURE-----
 
 iQFPBAABCgA5FiEEh7BulGwFlgAOi5DV2/sHvwUrPxsFAmqEbbEbHG1hc2FtaS5o
 aXJhbWF0c3VAZ21haWwuY29tAAoJENv7B78FKz8bpXsH/i61CqF8bt3/BNUG5qTV
 JP/j/Znl9utOq4+g01AeSt6tJREEp262w/b4ZwdXiu+Q41VYwyGazY93FxtX3rQC
 gcYnJcAGghzNUjf7ujI2VXDYa11t+GiYSR3Jv8hc/Xu7rq/ilExLObFwJfdhNZAb
 go7mC0x9TgRAyw/k/9ezwukBcXQUsuoBU3+IFvict9BrSVmvMPNFhCyvIi6Ps5Fj
 NldKTDAaWiKUOuIBDF1vXXSbHMoec31qNll/Ps4HG8RLpdrSWbW4nTOaazir2bbS
 RA6hUlVNwsYn7UN6x/taV2szojyAODDv1r6ULplCVjbsn5M0TcdmLFW8JUimaAIr
 wm0=
 =6KXI
 -----END PGP SIGNATURE-----

Merge tag 'probes-v7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull probes updates from Masami Hiramatsu:
 "BTF typecasting and variable fetch enhancements:

   - Typecast support across probe events: Extended BTF typecasting
     syntax (e.g., (STRUCT)PARAM->MEMBER) to kprobes, uprobes, and
     fprobes on function entry and return

   - Nested typecasts: Added support for chaining and nesting typecasts
     up to 3 levels, including casting registers and stack variables

   - Field specifier option: Added (STRUCT,FIELD) syntax to emulate
     container_of(), allowing retrieval of parent structures from member
     pointers

   - $current variable support: Introduced $current special variable to
     access the running task_struct via BTF dereferencing

   - Per-CPU variable access: Added this_cpu_read() and this_cpu_ptr()
     fetcharg methods to trace CPU-local data safely

   - Fetcharg bytecode dumper: Added CONFIG_PROBE_EVENTS_DUMP_FETCHARG
     to dump the compiled fetcharg bytecode instructions as comments in
     dynamic_events

   - Extended symbol name handling: Removed the MAX_COMMON_HEAD_LEN
     limit and extended MAX_ARGSTR_LEN to 256 bytes, enabling probing of
     long symbols, mangled Rust symbols and complex BTF expressions

   - eprobe variable syntax: Allowed eprobes to reference event fields
     directly without requiring a '$' prefix

   - Cleanup unused parameters, redundant codes, duplicate macros and
     pointer arithmetic

   - Use a ternary operator for simplifying fetch_type_from_btf_type()

  Expanded boot time dynamic probe support:

   - Add boot-time tracing configuration support for event probes
     (eprobes), function probes (fprobes), and tracepoint probes
     (tprobes)

   - Allow comment lines ('#') in dynamic_events file

  Optimization, robustness, and cleanups:

   - Simplify fprobe_remove_ips() by reusing graph and ftrace helpers

   - Remove __packed attribute from struct __fprobe_header to avoid
     unaligned memory access penalties on RISC architectures

   - Remove redundant memset() calls in perf event probe handlers

   - Replace legacy __ASSEMBLY__ with __ASSEMBLER__ in header files

  Selftests & refactoring:

   - Refactor parse_probe_arg() and parse_probe_vars(), and eliminate
     recursion in probe argument parsing to protect kernel stack depth

   - Add selftests for BTF typecasts and module probing without module
     prefixes

   - Force LC_ALL=C in ftracetest to prevent test failures on localized
     systems

   - Refactor btf_type_skip_modifiers() to remove ignored id parameter

   - Sort ERRORS list in trace_probe.h alphabetically

   - Fix typo in fprobe docs, and trace_fprobe function name

   - Rename FETCH_OP_DATA to FETCH_OP_IMMSTR

   - Make file offset error message probe-agnostic"

* tag 'probes-v7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (37 commits)
  fprobe: Simplify fprobe_remove_ips() by reusing existing helpers
  tracing/boot: Add support for eprobe, fprobe, and tprobe events
  selftests/ftrace: Force C locale in ftracetest
  tracing/probes: Treating longer symbol name on event comparation
  docs: trace: fprobe: fix 'thos' spelling
  tracing/probes: Fix extra whitespace in trace_probe_kernel.h
  tracing/kprobe: Remove redundant memset in kprobe_perf_func()
  tracing/fprobe: Remove redundant memset in fentry_perf_func()
  tracing/fprobe: Remove redundant snprintf in trace_fprobe_match_command_head()
  tracing/probes: Simplify BTF_KIND_PTR case in fetch_type_from_btf_type()
  tracing/probes: Cleanup pointer arithmetic in store_trace_entry_data()
  tracing/probes: Remove unused parameter from parse_probe_var_retval()
  tracing/probes: Remove redundant bounds check in trace_probe_compare_arg_type()
  tracing/probes: Remove redundant boolean conversion in trace_probe_has_single_file()
  tracing/probes: Remove duplicate MAX_ARRAY_LEN macro definition
  selftests/ftrace: Add test case for a symbol in a module without module name
  tracing/probes: Eliminate recursion in parse_probe_arg()
  tracing/probes: Extend max length of argument string
  tracing/probes: Sort ERRORS list in trace_probe.h alphabetically
  tracing/probes: Refactor parse_probe_arg()
  ...
2026-08-20 15:11:52 -07:00
arch RISC-V updates for v7.3 2026-08-20 14:53:54 -07:00
block for-7.3/block-20260819 2026-08-20 13:55:16 -07:00
certs treewide: fix indentation and whitespace in Kconfig files 2026-05-28 21:24:42 -07:00
crypto This update includes the following changes: 2026-08-19 17:25:42 -07:00
Documentation Probes updates for v7.3: 2026-08-20 15:11:52 -07:00
drivers CXL for v7.3 2026-08-20 15:02:09 -07:00
fs for-7.3/block-20260819 2026-08-20 13:55:16 -07:00
include Probes updates for v7.3: 2026-08-20 15:11:52 -07:00
init sched_ext: Changes for v7.3 2026-08-20 11:01:37 -07:00
io_uring for-7.3/block-20260819 2026-08-20 13:55:16 -07:00
ipc vfs-7.3-rc1.lookup 2026-08-17 12:03:34 -07:00
kernel Probes updates for v7.3: 2026-08-20 15:11:52 -07:00
lib for-7.3/block-20260819 2026-08-20 13:55:16 -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 for-7.3/block-20260819 2026-08-20 13:55:16 -07:00
net for-7.3/block-20260819 2026-08-20 13:55:16 -07:00
rust lsm/stable-7.3 PR 20260814 2026-08-19 16:28:23 -07:00
samples Probes updates for v7.3: 2026-08-20 15:11:52 -07:00
scripts It has been a not-too-busy cycle for docs; here's the highlights: 2026-08-20 10:31:50 -07:00
security integrity-v7.3 2026-08-19 17:17:17 -07:00
sound sound updates for 7.3-rc1 2026-08-19 10:04:59 -07:00
tools Probes updates for v7.3: 2026-08-20 15:11:52 -07:00
usr usr: Correct a spelling by changing a letter 2026-08-05 14:51:58 +02:00
virt KVM/arm64 fixes for 7.2, take #2 2026-07-15 12:13:30 +02:00
.clang-format clang-format: fix formatting of guard() and scoped_guard() statements 2026-05-28 21:24:41 -07:00
.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 2026-04-02 16:48:25 +02:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore SPDX patches for 7.2-rc1 2026-06-22 12:06:22 -07:00
.mailmap There is a known WiFi/mt76 regression, waiting for a complete fix that 2026-08-13 08:37:26 -07:00
.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 It has been a not-too-busy cycle for docs; here's the highlights: 2026-08-20 10:31:50 -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 RISC-V updates for v7.3 2026-08-20 14:53:54 -07:00
Makefile Kbuild/Kconfig updates for 7.3 2026-08-18 09:26:31 -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