Linus Torvalds 5a8cd539ac Merge tag 'bpf-next-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Pull bpf updates from Daniel Borkmann:
 "Major changes:

   - Redesign the verifier error reporting: failures now carry source
     and instruction annotations along with the causal event history
     that led to them, making program rejections far easier to debug and
     repair (Kumar Kartikeya Dwivedi)

   - Add arena argument support to kfuncs and struct_ops through the new
     __arena and __arena__nullable suffixes (Tejun Heo, Puranjay Mohan,
     Kumar Kartikeya Dwivedi, Ihor Solodrai)

   - Signed BPF program loader rework to accommodate both BPF and
     security community needs where the kernel runs the signature
     verification at BPF_PROG_LOAD time before the LSM admission hook
     (Daniel Borkmann)

   - Add a set of ksock kfuncs which let BPF LSM and syscall programs
     create, connect and send on UDP sockets in order to emit telemetry
     data (Mahe Tardy)

   - Unify helper and kfunc call argument verification and classify
     kfunc arguments purely from BTF into a generated bpf_func_proto
     which is computed once at add-call time (Amery Hung)

  Other features and fixes:

   - Enable EXECMEM_ROX_CACHE for BPF allocations on x86 (Mike Rapoport)

   - Add bidirectional VLAN support to bpf_fib_lookup() through the new
     BPF_FIB_LOOKUP_VLAN and BPF_FIB_LOOKUP_VLAN_INPUT flags (Avinash
     Duduskar)

   - Infer zext_dst from static register liveness analysis to fix 32-bit
     zero-extension semantics, and remove the artificial limitations on
     pointer types eligible for spilling (Eduard Zingerman)

   - Inline the numeric open-coded iterator kfuncs so that bpf_for()
     loops no longer pay a kfunc call on every iteration (Puranjay
     Mohan)

   - Add an arena-based bitmap data structure to libarena along with
     serial and parallel selftests (Emil Tsalapatis)

   - Teach resolve_btfids to discover kfuncs from the kernel's BTF ID
     sets and to emit kfunc BTF decl tags, reducing the kernel build's
     dependency on pahole features (Ihor Solodrai)

   - Add BPF_F_ADJ_ROOM_DECAP_* flags to bpf_skb_adjust_room() so that
     tunnel decapsulation can update the GSO and encapsulation state of
     the skb (Nick Hudson)

   - Fix the ring buffer pending_pos walk and the available-data
     accounting on 32-bit position wrap (Israel Téllez García)

   - Add memory usage accounting for arena maps and fix an mmap_lock
     deadlock on arena lock failure (Jiayuan Chen)

   - Add tracing_multi link info support to the kernel UAPI and bpftool,
     and refactor the stack map code to run with preemption disabled
     (Jiri Olsa)

   - Support BPF_F_EGRESS in bpf_redirect_peer() to emit the skb in the
     egress direction of the target's peer device (Jordan Rife)

   - Add a KF_SPINLOCK_SAFE kfunc flag so that providers, in particular
     modules, can declare kfuncs safe to call under bpf_spin_lock
     instead of relying on the verifier's hard-coded allowlist (Kaitao
     Cheng)

   - Introduce global percpu data for BPF programs with libbpf probing
     and bpftool skeleton support, and stop exposing uninitialized
     kernel heap memory when copying per-CPU map values (Leon Hwang)

   - Add s390 JIT support for load-acquire and store-release
     instructions (Maxim Khmelevskii)

   - Fix a CFI mismatch in the task work callback and an arm64 KASAN
     false positive after bpf_throw() (Mykyta Yatsenko)

   - Reject writes through untrusted BTF pointers and bound the
     rdonly/rdwr_buf_size kfunc arguments (Nicholas Dudar)

   - Invalidate RCU pointers only after the final spin unlock and
     account for preempt and IRQ disabled regions as overlapping RCU
     protection (Ning Ding)

   - Support mixing bpf2bpf calls and tail calls on RV64, add signed
     operations and 32-bit atomics to the RV32 JIT, and add timed
     may_goto support (Pu Lehui, Kuan-Wei Chiu, Feng Jiang)

   - Fix a use-after-free on mm_struct in bpf_find_vma() for foreign
     tasks and an mmap_lock leak in the irq_work path (Sanghyun Park)

   - Populate mmap-able BPF array map memory lazily which makes mmap()
     O(1) instead of proportional to the map size (Song Liu)

   - Introduce a jit_required flag and reject programs with inlined
     helpers when no JIT is available, where the interpreter would
     otherwise jump into an invalid address (Tiezhu Yang)

   - Fix the x86 JIT per-CPU address resolution into an extended
     register where the REX prefix dropped the high destination register
     bit (Vineet Gupta)

   - Reject MEM_ALLOC BTF accesses past object bounds, arena frees below
     the arena base, and mixed arena and ordinary atomic paths (Yiyang
     Chen)

   - Fix the trampoline handling of 128-bit arguments and of return
     values larger than 8 bytes (Yonghong Song)

   - Ensure that any fault prone load is rewritten with exception table
     handling, and fix the arena load-acquire and atomic fetch handling
     in the x86, arm64, riscv and s390 JITs (Daniel Borkmann)

   - Many more fixes and cleanups across the verifier, arena,
     trampolines, sockmap, cgroup, ring buffer, x86/arm64/riscv/s390
     JITs, libbpf, bpftool, resolve_btfids and selftests"

* tag 'bpf-next-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (373 commits)
  selftests/bpf: Add tests for a store on a fault prone qdisc pointer
  selftests/bpf: Add tests for fault prone loads out of RCU pointers
  selftests/bpf: Add tests for pointer type merge at a shared load
  selftests/bpf: Remove duplicate copies of the arena spinlock qnodes
  selftests/bpf: Retry stat generation in cgroup_iter_memcg
  selftests/bpf: Test pseudo-function policy diagnostics
  bpf: Distinguish function references in policy diagnostics
  bpf: Preserve source attribution without source text
  selftests/bpf: Test kfunc argument diagnostics
  bpf: Correct kfunc argument diagnostics
  bpf: Use canonical stack argument names in diagnostics
  bpf: Preserve R0 lineage across helper calls
  selftests/bpf: Exercise negative optlen in cgroup getsockopt hook
  bpf: Reject negative optlen in cgroup getsockopt hook
  selftests/bpf: tc_tunnel - validate decap GSO and encapsulation state
  bpf: Clear decap state on skb_adjust_room shrink path
  bpf: Allow new DECAP flags and add guard rails
  bpf: Add BPF_F_ADJ_ROOM_DECAP_* flags for tunnel decapsulation
  bpf: Refactor masks for ADJ_ROOM flags and encap validation
  bpf: Name the enum for BPF_FUNC_skb_adjust_room flags
  ...
2026-08-20 07:36:20 -07:00
2026-01-26 19:07:09 -08:00
2022-09-28 09:02:20 +02:00
2025-02-19 14:53:27 -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
* 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
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