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Non-uniform memory access (NUMA) systems are organized with their CPUs grouped into nodes, each of which has memory attached to it. All memory in the system is accessible from all CPUs, but memory attached to the local node is faster. The kernel's memory-policy ("mempolicy") interface allows threads to inform the kernel about how they would like their memory placed to get the best performance. In recent years, the NUMA concept has been extended to support the management of different types of memory in a system, pushing the limits of the mempolicy subsystem. In a remotely presented session at the 2024 Linux Storage, Filesystem, Memory Management, and BPF Summit, Gregory Price discussed the ways in which the kernel's memory-policy support should evolve to handle today's more-complex systems.

Working on the Linux kernel has always been unlike working on many other software projects. One particularly noticeable difference is the decentralized nature of the kernel's testing infrastructure. Projects such as syzkaller, KernelCI, or the kernel self tests test the kernel in different ways. On February 28, Helen Koike posted a patch set that would add continuous integration (CI) scripts for the whole kernel. The response was generally positive, but several people suggested changes.

The 6.9.1, 6.8.10, 6.6.31, 6.1.91, 5.15.159, 5.10.217, 5.4.276, and 4.19.314 stable kernels have been released. These versions include several important fixes; as usual, Greg Kroah-Hartman advises users to update right away.

The DAMON subsystem was the subject of the first session in the memory-management track at the Linux Storage, Filesystem, Memory Management, and BPF Summit. DAMON maintainer SeongJae Park introduced the data-access monitoring framework, which can generate snapshots of how memory is accessed, enabling the detection of hot and cold regions of memory in both the virtual and physical address spaces. The session covered recent changes and future plans for this tool.

Security updates have been issued by Fedora (chromium, firefox, and podman), Mageia (chromium-browser-stable, ghostscript, and java-1.8.0, java-11, java-17, java-latest), Red Hat (bind, Firefox, firefox, gnutls, httpd:2.4, and thunderbird), SUSE (glibc, opera, and python-Pillow), and Ubuntu (dotnet7, dotnet8, linux, linux-aws, linux-aws-5.4, linux-azure, linux-azure-5.4, linux-bluefield, linux-gcp, linux-gcp-5.4, linux-gkeop, linux-hwe-5.4, linux-ibm, linux-ibm-5.4, linux-iot, linux-kvm, linux-oracle, linux-oracle-5.4, linux-raspi, linux-raspi-5.4, linux-xilinx-zynqmp, linux, linux-aws, linux-aws-6.5, linux-azure, linux-azure-6.5, linux-gcp, linux-gcp-6.5, linux-hwe-6.5, linux-laptop, linux-lowlatency, linux-lowlatency-hwe-6.5, linux-nvidia-6.5, linux-oem-6.5, linux-oracle, linux-oracle-6.5, linux-raspi, linux-signed, linux-signed-aws, linux-signed-aws-6.5, linux-starfive, linux-starfive-6.5, linux, linux-aws, linux-azure-4.15, linux-gcp-4.15, linux-hwe, linux-kvm, linux-oracle, linux, linux-aws, linux-kvm, linux-lts-xenial, and linux, linux-azure, linux-azure-5.15, linux-azure-fde, linux-azure-fde-5.15, linux-gcp, linux-gcp-5.15, linux-gkeop, linux-gkeop-5.15, linux-hwe-5.15, linux-ibm, linux-ibm-5.15, linux-intel-iotg, linux-kvm, linux-lowlatency, linux-lowlatency-hwe-5.15, linux-nvidia, linux-oracle, linux-raspi).

Ronnie Sahlberg, Jonathan Maple, and Jeremy Allison of CiQ have published a white paper looking at the security-relevant bug fixes applied (or not applied) to the RHEL 8.x kernel over time.

This means that over time, the security of the RHEL kernels get worse and worse as more issues are discovered in the upstream code and are potentially exploitable but fewer and fewer of the fixes for these known bugs are back-ported into RHEL kernels.

After reaching RHEL 8.7, the theory is that the kernel has been stabilized, with a corresponding improvement in security. However we still have an influx of newly discovered bugs in the upstream kernel affecting RHEL 8.7 that are not addressed. Each minor version of upstream is released on an approximately quarterly basis and we can see that the influx of new bugs that are unaddressed in RHEL is growing. The number of known issues in these kernels increases by approximately 250 new bugs per quarter or more.

The merge window for the 6.10 kernel release opened on May 12; between then and the time of this writing, 6,819 non-merge commits were pulled into the mainline kernel for that release. Your editor has taken some time out from LSFMM+BPF in an attempt to keep up with the commit flood. Read on for an overview of the most significant changes that were pulled in the early part of the 6.10 merge window.

Version 0.10 of the Vim-based text editor Neovim is now available. This release includes a new default color scheme, enhanced support for rendering multibyte characters, support for hyperlinks, system clipboard synchronization, and more. Many features have been deprecated in 0.10 and will be removed in future release. Neovim core contributor Gregory Anders has written a summary of some of the highlights and thoughts on upcoming releases:

We follow a "fun driven development" paradigm: for the most part, contributors and maintainers work on things that are personally interesting to them. Because of this, it can be difficult to predict what will happen in future releases. If there is a feature you want to see implemented, the best way to do it is to take a crack at it yourself: many of the features mentioned in this very blog post were contributed by users that are not part of the "core" maintenance team!

Security updates have been issued by AlmaLinux (.NET 7.0, .NET 8.0, and nodejs:20), Debian (chromium, firefox-esr, ghostscript, and libreoffice), Fedora (djvulibre, mingw-glib2, mingw-python-jinja2, and mingw-python-werkzeug), Oracle (.NET 7.0, .NET 8.0, kernel, and nodejs:18), Red Hat (nodejs:20), Slackware (gdk and git), SUSE (python), and Ubuntu (linux-hwe-5.15, linux-raspi).

The LWN.net Weekly Edition for May 16, 2024 is available.

The Mozilla Foundation has announced that its new executive director will be Nabiha Syed.

Syed is known for her mission-driven leadership, focused on increasing transparency into the most powerful institutions in society. She comes to Mozilla after leading The Markup, an award-winning publication that challenges technology to serve the public good, from its launch through its successful acquisition in 2024.

Ars technica looks at a a recent report on the Ebury root kit, with a focus on the 2011 compromise of kernel.org, which may have been more extensive than believed at the time.

In 2014, ESET researchers said the 2011 attack likely infected kernel.org servers with a second piece of malware they called Ebury. The malware, the firm said, came in the form of a malicious code library that, when installed, created a backdoor in OpenSSH that provided the attackers with a remote root shell on infected hosts with no valid password required. In a little less than 22 months, starting in August 2011, Ebury spread to 25,000 servers. Besides the four belonging to the Linux Kernel Organization, the infection also touched one or more servers inside hosting facilities and an unnamed domain registrar and web hosting provider.

Version 126.0 of the Firefox browser is out. Changes include improvements to the "copy link without site tracking" feature, support for zstd compression, and a new tracking "feature": "Telemetry was added to create an aggregate count of searches by category to broadly inform search feature development."

The advent of the folio structure to describe groups of pages has been one of the most fundamental transformations within the kernel in recent years. Since the folio transition affects many subsystems, it is fitting that the subject was covered at the beginning of the 2024 Linux Storage, Filesystem, Memory Management, and BPF Summit in a joint session of the storage, filesystem, and memory-management tracks. Matthew Wilcox used the session to review the work that has been done in this area and to discuss what comes next.

Security updates have been issued by Mageia (sssd and tcpdump), Red Hat (.NET 7.0, .NET 8.0, expat, kernel, and kernel-rt), Slackware (mozilla), SUSE (kernel, postgresql15, postgresql16, python-arcomplete, python-Fabric, python-PyGithub, python- antlr4-python3-runtime, python-avro, python-chardet, python-distro, python- docker, python-fakeredis, python-fixedint, pyth, and python3), and Ubuntu (linux-bluefield).

Version 24.0 of the Arch-based Manjaro distribution is now available with the 6.9 kernel, GNOME 46, Xfce 4.18, and an update to the Pamac package installer. This is also the project's first release with KDE Plasma 6:

The Plasma edition comes with the latest Plasma 6.0 series and KDE Gear 24.02. It brings exciting new improvements to your desktop.

With Plasma 6, KDE's technology stack has undergone major upgrades: a transition to the latest version of application framework, Qt, and an improved graphics platform when Wayland is used. These changes are as smooth and unnoticeable to the users as possible. You will see the same familiar desktop environment that you know and love. But these under-the-hood upgrades benefit Plasma's security, efficiency, and performance, and improve support for modern hardware. Thus Plasma delivers an overall more reliable user experience, while paving the way for many more improvements in the future.

The project also offers minimal install images with the 6.6 LTS and 6.1 LTS kernels to support older hardware.

Large language models (LLMs) have been the subject of much discussion and scrutiny recently. Of particular interest to open-source enthusiasts are the problems with running LLMs on one's own hardware — especially when doing so requires NVIDIA's proprietary CUDA toolkit, which remains unavailable in many environments. Mozilla has developed llamafile as a potential solution to these problems. Llamafile can compile LLM weights into portable, native executables for easy integration, archival, or distribution. These executables can take advantage of supported GPUs when present, but do not require them.

Security updates have been issued by Debian (glib2.0 and shim), Fedora (glib2, gnome-shell, tcpdump, tpm2-tools, tpm2-tss, and uriparser), Mageia (mutt), Oracle (git-lfs, glibc, kernel, kernel-container, nodejs:18, nodejs:20, and pcp), SUSE (apache2, opensc, openssl-1_1, openssl-3, perl, python-Pillow, python-pyOpenSSL, python-Werkzeug, SUSE Manager Client Tools Beta, tpm2-0-tss, and tpm2.0-tools), and Ubuntu (sqlparse and strongswan).

The 6.9 kernel was released on May 12 after a typical nine-week development cycle. Once again, this is a major release containing a lot of changes and new features. Our merge-window summaries (part 1, part 2) covered those changes; now that the development cycle is complete, the time has come to look at where all that work came from — and to introduce a new and experimental LWN feature for readers interested in this kind of information.

Maintainers of open-source projects sometimes have disagreements with contributors over how contributions are reviewed, modified, merged, and credited. A written policy describing how contributions are handled can help maintainers set reasonable expectations for potential contributors. In turn, that can make the maintainer's job easier because it can help reduce a source of friction in the project. A guide to help create this kind of policy for a project has recently been developed.