As a professor of biomedical engineering, Martin Uecker perhaps does not fit the profile of a typical presenter at Kernel Recipes. He is, however, a longtime Linux user, and works on free software for controlling magnetic resonance imaging (MRI) scanners. He was at the conference to talk about the C programming language, the specific problem of undefined behavior in C, and whether it can eventually be made into a memory-safe language.

The 7.3-rc5 kernel prepatch is out for testing. Linus said: "I don't think there's any real pattern to it other than 'big'. But nothing looks particularly alarming, I think that despite the diffstat it's just the same old, same old."

Version 18.1 of the GDB interactive debugger has been released. Changes include new commands to manipulate the environment of the subprocess, the ability to save the command history to a file, support for a couple of new targets, several Python API additions, and more. See the NEWS file for the complete list.

Johannes Schindelin has posted a detailed summary of the discussions held at the 2026 Git Contributors' Summit. Topics covered include Git 3.0, security process, documentation, the pluggable object database, use of LLMs, and more.

Inside this week's LWN.net Weekly Edition:

• Front: Git 2.56; gccrs; NetBSD and compat_linux; io_uring; Desktop UX.
• Briefs: WordPress vulnerability; Radicle vulnerability; Systemtap 5.6; GNOME 51; Systemd v262; Quotes; ...
• Announcements: Newsletters, conferences, security updates, patches, and more.

The Git source-code management system is at the core of development processes worldwide, so changes, especially incompatible changes, are of great interest to the developers involved. The Git 2.56 release, which can be expected around the end of September, is currently available in release-candidate form. It is not the most earth-shaking of releases, but the one that follows, which might be the long-awaited Git 3.0, may well be.

Version 5.6 of the Systemtap tracing tool has been released.

BPF LSM hooks and XDP packet-processing probes for the --bpf runtime, BTF-based kernel.tracepoint probes, statement execution tracing, a new @enumname() operator, richer runtime error context, dyninst hardware watchpoints, modern systemd service templates, and broad Linux 7.2 runtime/tapset compatibility work. Multithreaded speedups throughout.

Security updates have been issued by AlmaLinux (.NET 10.0, coreutils, kernel, libevent, libsoup3, microcode_ctl, perl-Net-DNS, postgresql18, postgresql:16, postgresql:18, tomcat, and unbound), Debian (bind9, chromium, libapache2-mod-auth-openidc, nginx, xz-utils, and zip), Fedora (chromium, freeipmi, GitPython, gnatcoll, nodejs-undici, parted, python-django5, and sblim-cmpi-base), Mageia (imagemagick and python-starlette), Oracle (.NET 10.0, .NET 8.0, .NET 9.0, coreutils, corosync, firewalld, kernel, libevent, libsoup, microcode_ctl, nginx:1.24, perl, perl:5.32, postgresql:16, postgresql:18, redis, rsync, rsyslog, tesseract, and unbound), Red Hat (vim), SUSE (alsa, chirp, chromium, cjose, cups, discount, firefox, gh, glibc, gvfs, jq, kernel, libcjose-devel, libmbedcrypto7, libpcap, mbedtls-2, netcdf, nodejs18, openai-codex, openvpn, pcre2, perl-net-dns, sngrep, tiff, and znc), and Ubuntu (bison, bubblewrap, and gst-plugins-good1.0).

The io_uring subsystem is all about asynchronous execution; applications count on it to not block — unless explicitly requested to. Within io_uring, maintaining the "never blocks" guarantee has sometimes been a challenge, given that many paths in the kernel were never designed for asynchronous execution. This problem has been worked around, but at a significant cost to performance. Now, io_uring maintainer Jens Axboe has posted an RFC patch set with a somewhat radical (and potentially scary) solution to the problem.

Version 51 of the GNOME desktop environment has been released. The list of changes includes a number of performance improvements, offline data and better transit information in the Maps application, a new interface for the file previewer, and more.

Security updates have been issued by AlmaLinux (.NET 10.0, .NET 8.0, .NET 9.0, corosync, firewalld, kernel, kernel-rt, libevent, libsoup, microcode_ctl, nginx:1.26, python-lxml, rsyslog, tesseract, and unbound), Debian (firefox-esr, mkvtoolnix, thunderbird, and tor), Fedora (open62541, php-pecl-mongodb2, python-django6, python-jwcrypto, and roundcubemail), Mageia (aom, cockpit, libgd, packagekit, and python-h2), Red Hat (corosync, delve, git-lfs, grafana-pcp, gstreamer1-plugins-base, libvirt, opentelemetry-collector, and rhc-worker-playbook), Slackware (mozilla-firefox and mozilla-thunderbird), SUSE (acl, attr, alloy, ansible-core, clamav, containerized-data-importer, corosync, cups, distribution, glibc, google-cloud-sap-agent, govulncheck-vulndb, gvfs, helm, jq, kbd, kubernetes1.34-apiserver, kubernetes1.35-apiserver, lcms2, libcupsfilters, liblzmasdk26, libzypp, zypper, mistral-vibe, opensc, openvpn, pcre2, python-jwcrypto, tomcat, tomcat10, and tomcat11), and Ubuntu (guix, libheif, perl, python-cryptography, sqlite3, and valkey).

The Register looks forward to the upcoming Fedora 45 release.

The biggest surprise is that Linux's legacy in-kernel console – the text-mode interface normally hidden beneath the GUI – has been replaced with a software-controlled alternative. The replacement is kmscon, a userspace terminal emulator that has been in development for more than a decade.

Security updates have been issued by AlmaLinux (kernel, kernel-rt, libkcapi, nginx, nginx:1.24, openssl, osbuild-composer, perl, perl:5.32, python-tornado, rsync, and rust), Debian (cjose and nginx), Fedora (environment-modules, erlang, GitPython, knot, perl-Authen-SASL, python-configargparse, ruby, rubygems, and sblim-sfcb), Oracle (firefox, git-lfs, gstreamer1-plugins-base, kernel, libkcapi, nginx, nginx:1.26, openssl, osbuild-composer, perl, perl-YAML-Syck, postgresql18, python-tornado, and rust), Red Hat (fence-agents, git-lfs, microcode_ctl, osbuild-composer, podman, python-pyasn1, and resource-agents), SUSE (389-ds, ant, bson-devel, chirp-20260911, docker, gimp, google-cloud-sap-agent, hauler, kernel, kimi-code, libpcap, python-GitPython, python310, syncthing, yast2-samba-client, and zstd-jni), and Ubuntu (aom, imagemagick, kitty, openssh, phpseclib, policykit-1, python-sql, python-webob, shibboleth-sp, simplesamlphp, snapcast, srt, and suricata-update).

The scheduling of block I/O requests has long been a challenge for operating-system kernels. For many years, the performance characteristics of rotating drives meant that putting considerable resources into request ordering was worthwhile. In a world with fast, solid-state drives, scheduling is more concerned with enforcing fairness between competing users while being fast enough to keep up with drives that can perform millions of I/O operations per second. The blk-iocost I/O controller was designed for the solid-state world and generally performs well, but there is always a desire to do better. This patch series from Tao Cui aims to make blk-iocost more flexible by enabling the loading of a BPF program to make cost decisions.

Just a reminder that prices for LWN subscriptions will increase after September 15. Until then, the older rate still applies. See this article for details on this change. Thanks, yet again, to all of our subscribers for your support — that is what keeps LWN going.

The 7.3-rc3 kernel prepatch is out for testing. Linus said: "Another fairly large rc release, and again one with a bigger filesystem footprint that we usually see."

Kernel developers do a lot of kernel builds. Since the kernel is not a small program, those builds can take a fair amount of time, even on a fast machine. The kernel also has a complex build system; it is probably fair to say that few developers truly understand it, and fewer still are willing to try to improve it. Lorenzo Stoakes, armed with LLM-based assistance, decided to give it a try, though, and has managed to reduce the time it takes to build a kernel — and not by a small amount.

The restartable sequences feature is one of the stranger corners of the kernel's user-space interface; it provides a way for user space to carry out simple lockless operations and be informed if it is preempted over the course of an operation (and must, thus, restart). Work merged in the 6.19 release to improve the performance of restartable sequences broke the TCMalloc allocator, which was relying on an undocumented (and unintended) kernel behavior. Now, Olivier Dion is proposing an addition to the restartable-sequences API that will bring TCMalloc back into the fold; it does not make the restartable-sequences API any less strange, though.

The 7.3-rc2 kernel prepatch is out for testing. Linus said:

This didn't *feel* like a particularly busy rc2, but it clearly was. rc2 is usually the quietest time when people take a breather after the merge window and it takes a while to start finding bugs. But not this time - this is a "full fat" rc release. [...]

Nothing looks particularly odd, even if the rc2 timing is a bit unusual. It might be just random, but we'll obviously all blame it on AI, because whether that's really the cause or not, it's an easy thing to blame ;)

Tiered-memory systems are built with multiple types of memory, each of which has different performance characteristics. In addition to the usual DRAM, a tiered system might also provide faster high-bandwidth memory or slower CXL memory. On these systems, the placement of memory allocations has a significant effect on the performance that a workload will obtain. While work on tiered-memory improvements has been ongoing for years, it feels like the pace has slowed a bit recently. Even so, there are a few efforts underway, but they are facing questions about whether the tiering design makes sense.