Post Syndicated from daroc original https://lwn.net/Articles/1082948/

Tracepoints in the kernel are useful for a variety of purposes: debugging,
active monitoring, and performance measurements, among other things. Previously,
any given BPF program could only be attached to a single tracepoint.
Jiri Olsa has been working to change that, and led a discussion about
his progress at the 2026

Linux Storage, Filesystem, Memory-Management, and BPF
Summit. That work has since been

merged, and can be expected as part of the 7.2
kernel.

Post Syndicated from daroc original https://lwn.net/Articles/1082111/

Since 2020, BPF programs have been able to

act as Linux security modules
(LSMs). Several projects, including systemd, have been working to use
that capability to provide more security to users. Christian Brauner
spoke at the 2026

Linux Storage, Filesystem, Memory-Management, and BPF Summit
about some of the limitations of using BPF in this way, and the changes he
would like to see for systemd’s use. In particular, he would like a way to make
sure that BPF programs cannot be removed or have their private data tampered with.

Post Syndicated from daroc original https://lwn.net/Articles/1081696/

Tetragon, the BPF-based security monitoring tool,
uses BPF to monitor different aspects of a running kernel and
enforce user-specified policies. It sends its data to a user-space process,
which forwards the data to a central monitoring service elsewhere in the
network, however. This
presents a point of vulnerability: if an attacker can kill Tetragon’s user-space
agent, it won’t be able to properly report on the situation. Song Liu, Mahé
Tardy, and Liam Wiseheart spoke about their work removing the need for the
user-space agent at the 2026

Linux Storage, Filesystem, Memory-Management, and
BPF Summit.

Post Syndicated from daroc original https://lwn.net/Articles/1082832/

Security updates have been issued by AlmaLinux (389-ds:1.4, buildah, freeipmi, freerdp, gegl, gimp, golang, kernel, libreoffice, maven:3.9, openexr, perl-DBI, plexus-utils, podman, tomcat, tomcat9, xorg-x11-server, and xorg-x11-server-Xwayland), Debian (imagemagick, p7zip, and redis), Fedora (breezy, calibre, and golang-github-openprinting-ipp-usb), Mageia (ffmpeg, gzip, haproxy, libheif, libtiff, libxml2, packages, perl-List-SomeUtils-XS, and perl-Socket), SUSE (alsa, chromedriver, curl, dhcpcd, docker-compose, glibc, haproxy, ImageMagick, jq, kernel, kubernetes, libpng15, libredwg-devel, libslirp, nghttp2, php8, python-Pillow, python313-Django, python313-weasyprint, qemu, rust-keylime, sccache, and systemd), and Ubuntu (cifs-utils, libexif, libreoffice, libssh2, openssh, and pipewire).

Post Syndicated from daroc original https://lwn.net/Articles/1081546/

Cisco has some unusual challenges when it comes to deploying security patches
across the company’s many devices running custom kernels. John Fastabend spoke
about his work preventing exploits with BPF at the 2026

Linux Storage,
Filesystem, Memory-Management, and BPF Summit.
The technique could substantially reduce the time necessary to respond to kernel
vulnerabilities, but it will not be fully effective unless more hooks are added
to the kernel.

Post Syndicated from daroc original https://lwn.net/Articles/1082647/

Debian has
announced the final normal update for Debian 12 (“bookworm”). Long-term-support updates will continue until 2028. As may be expected from a stable version, the update is mostly limited to security fixes. Still, it may be time for Debian users to look into upgrading to a more recent version. Conveniently, Debian 13 (“trixie”) also
received an update this weekend, with many of the same security fixes.

Post Syndicated from daroc original https://lwn.net/Articles/1082642/

Security updates have been issued by Debian (chromium, libxfont, mesa, opam, and wireless-regdb), Fedora (acl, attr, chromium, cjson, composer, docker-compose, jfrog-cli, librabbitmq, libssh2, libXfont2, log4cxx, OpenImageIO, openssh, p11-kit, perl-Crypt-DSA, perl-HTML-Gumbo, prometheus, python-dulwich, python-idna, python-pillow, python-tornado, sssd, tmux, upower, webkitgtk, xorg-x11-server, and xorg-x11-server-Xwayland), Mageia (libarchive and vim), Oracle (389-ds:1.4, buildah, cups, edk2, freerdp, golang, grafana, gstreamer1-plugins-bad-free, gstreamer1-plugins-good, gstreamer1-plugins-ugly-free, kernel, libexif, libsolv, libtasn1, libxml2, nginx:1.24, nginx:1.26, nodejs:22, nodejs:24, oci-seccomp-bpf-hook, podman, postgresql:18, python-urllib3, tigervnc, tomcat, unbound, and xorg-x11-server), Slackware (p11-kit), and SUSE (agama, dash, dracut, flannel, go1.26, gsasl, gstreamer-plugins-good, ImageMagick, imagemagick, kernel, krb5, krb5, krb5-mini, libIex-3_4-33, libmbedtls23, libxfont2, nasm, nghttp2, perl-CGI-Session, perl-dbi, perl-List-SomeUtils-XS, python-pillow, python-social-auth-app-django, python-urllib3, python313-Django4, python313-Django6, python313-pytest-html, python313-sqlparse, python313-websockets, rclone, rust-keylime, rustup, sccache, spectre-meltdown-checker, sssd, terraform-provider-aws, terraform-provider-azurerm, terraform-provider-external, terraform-provider-google, terraform-provider-helm, terraform-provider-kubernetes, terraform-provid, thunderbird, tiff, traefik2, xorg-x11-server, and xwayland).

Post Syndicated from daroc original https://lwn.net/Articles/1080519/

QBE, a compact compiler backend developed by Quentin Carbonneaux, is a
lightweight alternative to larger compiler backends such as LLVM and GCC.
Designed to be small enough for a single developer to understand, QBE uses a

static single-assignment (SSA) intermediate representation (IR), supports the C ABI,
and serves as the backend for projects such as Hare and
the cproc C11 compiler. Frontends
emit the textual form of QBE’s IR directly; QBE then takes care of register allocation,
optimization, and native-code generation, producing assembly for the target
architecture.

Post Syndicated from daroc original https://lwn.net/Articles/1081009/

Puranjay Mohan shared some of the

work he’s been doing recently on improving the
performance of read-copy-update (RCU) at the 2026

Linux
Storage, Filesystem, Memory-Management, and BPF Summit; his talk would have
been nice context to have earlier in the day when Harry Yoo and Alexei
Starovoitov led a session about the

new kmalloc_nolock() function that
allows for lockless allocation from any kernel context, and which interacts with
the RCU subsystem to allow that. This article therefore covers the two sessions
together and in the reverse order, to provide that missing context.

Post Syndicated from daroc original https://lwn.net/Articles/1078968/

When a BPF program is used to filter or redirect packets in the networking
subsystem, the program will often want to associate data with each packet as it
moves through the kernel. The kernel’s

local BPF storage API, which
associates extra data with some kernel objects, provides a way to do that. (See also
the BPF map types that end
in STORAGE.)
Amery Hung and Jakub Sitnicki led two sessions
at the 2026

Linux Storage, Filesystem, Memory-Management, and BPF Summit
about how to make accesses to local storage data more efficient. Hung spoke
about general performance problems related to locking, while Sitnicki examined
the use of local storage in the networking subsystem in particular.

Post Syndicated from daroc original https://lwn.net/Articles/1079001/

Lisp-like languages have historically led the world in metaprogramming and
flexibility. While many modern languages have adopted the idea of macros,
Lisp-like languages such as

Racket have continued pushing the envelope,
attempting to make macros as easy as possible to incorporate into everyday
programs. On the other hand, Lisp’s minimal, parenthesis-based syntax can be hard
to adapt to — to the point that Lisp is sometimes said to stand
for “Lots of Irritating Silly Parentheses”.

Rhombus is a new programming
language that aims to have the best of both worlds, marrying Racket’s
metaprogramming capabilities to a simple Python-like syntax and reasonable
standard-library defaults.

Post Syndicated from daroc original https://lwn.net/Articles/1078526/

BPF arenas are areas of memory (potentially shared with user space)
where programs have free reign to build their
own data structures, unburdened by the verifier’s bounds checks. Many of those
data structures are potentially usable in multiple programs. Emil Tsalapatis
brought his work on libarena, a library containing generic utilities for use in
BPF arenas, to the 2026

Linux Storage, Filesystem, Memory-Management, and BPF
Summit. Although the library is already available as part of the kernel, it
is still in its early stages and he has more work planned.

Post Syndicated from daroc original https://lwn.net/Articles/1077740/

Alexis Lothoré has been working to add support for the kernel’s memory-access
checker,

KASAN, to just-in-time-compiled BPF code. He spoke about that work at
the 2026

Linux Storage, Filesystem, Memory-Management, and BPF Summit.
KASAN support is needed, he said, to help catch bugs in the BPF just-in-time (JIT)
compiler. KASAN is a great tool for catching memory-management problems in the
kernel, but only in code that can be monitored by it.

Post Syndicated from daroc original https://lwn.net/Articles/1076210/

BPF programs can be used to extend many aspects the Linux kernel, but
BPF programs must run to completion in the same context that they began.
Kumar Kartikeya Dwivedi is working on changing that by
allowing BPF programs to be expressed as coroutines. He spoke about his work at
the 2026

Linux Storage, Filesystem, Memory-Management and BPF Summit. While
still experimental, the change promises to make long-running BPF tasks
significantly easier to write.

Post Syndicated from daroc original https://lwn.net/Articles/1074291/

How can cloud providers efficiently supply durable virtual block devices? Remote
Direct Memory Access (RDMA) provides a way for servers in a cluster to share
chunks of memory, but there still needs to be a protocol that operates on top of
RDMA to provide the guarantees expected of a block device. The kernel’s RDMA transport
library (RTRS) provides a way to send messages via RDMA. I
presented about two
new components built on top of RTRS at the 2026
Linux
Storage, Filesystem, Memory Management and BPF Summit: Reliable Multicast
over RTRS (RMR) and Block device over RMR (BRMR). These modules, which I
am working on with Jia Li, could be a way for cloud providers to
expose durable block devices with as little overhead as possible. To accomplish
that, however, we need some discussion and feedback from the community before
sending the modules upstream.

Post Syndicated from daroc original https://lwn.net/Articles/1076121/

The BPF verifier has, in the course of wrestling with the difficult problem of
statically analyzing loops, grown special support for many kinds of loops over its
history, but its fundamental approach to simple for loops has not
changed.
When it encounters a loop, it evaluates it, iteration by iteration, until reaching
an exit condition — a process that can cause the verifier to mistakenly hit the
limit on the number of allowed instructions where a better implementation
would not.
Eduard Zingerman
spoke at the 2026

Linux Storage, Filesystem, Memory-Management, and BPF Summit
about his in-progress work on improving the verifier’s treatment of loops, especially nested
loops.

Post Syndicated from daroc original https://lwn.net/Articles/1075067/

Alexei Starovoitov gave “less of a presentation, more of a scream of
realization” at the BPF track of the 2026

Linux Storage, Filesystem,
Memory-Management, and BPF Summit. He shared a set of ideas for how BPF could
change to avoid being swept away by the sea-change in programming represented by modern
large language models (LLMs) and the coding agents based on them.
In a follow-up session, the discussion covered
more problems with how coding agents use tools like bpftrace, and the current deluge of
patches in need of review in the BPF subsystem.

Post Syndicated from daroc original https://lwn.net/Articles/1073762/

Optimizing compilers can, under some circumstances, infer when a parameter to a
function is not needed, and remove it. This is all well and good until the
kernel’s tracing or BPF subsystems need information on how to call the function
or where its arguments are stored.
Alan Maguire and Yonghong Song spoke at the 2026

Linux
Storage, Filesystem, Memory-Management, and BPF Summit about their work on
recording information regarding changed function signatures in the kernel’s BTF debugging
information, to better support tracing such functions.

Post Syndicated from daroc original https://lwn.net/Articles/1070218/

MeshCore is a relatively new project, started in January 2025, that aims
to build a scalable mesh network using low-power long-distance radios. While
many other projects of the same general nature have been tried before, MeshCore
grew quickly because of its more efficient message routing and enthusiastic
community. In early 2026, an early proponent of the project made a sudden shift
that left the rest of the community stunned and embroiled in a trademark dispute.

Post Syndicated from daroc original https://lwn.net/Articles/1071973/

José Marchesi and the GCC-BPF developers opened the BPF track at the 2026

Linux Storage,
Filesystem, Memory-management, and BPF Summit
with a 90-minute summary of what has changed for GCC’s BPF support in the past year.
This kind of session has become something of a tradition. There were similar
updates in

2025 and

2024. This time around, GCC seems to be closing in on
feature parity with the LLVM toolchain — as the slides detail.