lwn.net

Linus has released 6.16-rc3 for testing. "So rc2 was smaller than usual, but rc3 seems to be right in the usual ballpark for this time, so everything looks entirely normal."

The Linux kernel is seeing a steady accumulation of Rust code. As it becomes more prevalent, maintainers may want to know how to read, review, and test the Rust code that relates to their areas of expertise. Just as kernel C code is different from user-space C code, so too is kernel Rust code somewhat different from user-space Rust code. That fact makes Rust's extensive documentation of less use than it otherwise would be, and means that potential contributors with user-space experience will need some additional instruction. This article is the first in a multi-part series aimed at helping existing kernel contributors become familiar with Rust, and helping existing Rust programmers become familiar with what the kernel does differently from the typical Rust project.

A new filesystem was the topic of a session led by Zach Brown at the 2025 Linux Storage, Filesystem, Memory Management, and BPF Summit (LSFMM+BPF). The ngnfs filesystem is not a "next generation" NFS, as might be guessed from the name; Brown said that he did not think about that linkage ("I hate naming so much") until it was pointed out to him by Chuck Lever in an email. It is, instead, a filesystem for enormous data sets that are mostly stored offline.

Debian's long-awaited tag2upload service is now ready for Debian maintainers to use in some circumstances. Tag2upload makes it easier for maintainers to upload packages, by allowing them to push a signed Git commit that will automatically be picked up and built, instead of pushing a build from their local machine. LWN covered the discussion around the service in July of last year. With the timing of its readiness, it's likely to become more useful once Debian 13 ("trixie") is released.

Be very aware of the freeze! Do not just upload to unstable as your first test! Uploads to unstable, targeting trixie, can be done with tag2upload - but in most cases you will probably want to upload the same package to experimental first.

Security updates have been issued by SUSE (apache2-mod_security2, augeas, ghc-pandoc, gstreamer, ignition, kernel, libblockdev, libxml2, nodejs20, openssl-3, pam_pkcs11, perl, python3, systemd, ucode-intel, webkit2gtk3, and xen) and Ubuntu (linux, linux-aws, linux-aws-5.4, linux-azure, linux-gcp, linux-gcp-5.4, linux-ibm, linux-ibm-5.4, linux-kvm, linux-oracle, linux-oracle-5.4, linux-xilinx-zynqmp, linux-aws-fips, linux-gcp-fips, python3.13, python3.12, and roundcube).

Born from research at the Southern University of Science and Technology (SUSTech) in Shenzen, China, Asterinas is a new Linux-ABI-compatible kernel project written in Rust, based on what the authors call a "framekernel architecture". The project overlaps somewhat with the goals of the Rust for Linux project, but approaches the problem space from a different direction by trying to get the best from both monolithic and microkernel designs.

Greg Kroah-Hartman has announced the release of the 6.15.3, 6.12.34, and 6.6.94 stable kernels. Each contains a relatively large number of important fixes throughout the kernel tree.

Security updates have been issued by AlmaLinux (gvisor-tap-vsock), Debian (activemq and chromium), Fedora (kea, python-django4.2, python-django5, python-setuptools, and rust-git-interactive-rebase-tool), Oracle (ipa and kernel), Red Hat (buildah, container-tools:rhel8, containernetworking-plugins, git-lfs, go-toolset:rhel8, golang, golang-github-openprinting-ipp-usb, grafana, grafana-pcp, gvisor-tap-vsock, podman, and skopeo), Slackware (libblockdev and xorg), SUSE (gdm, gstreamer-plugins-base, ignition, kernel, pam, redis, s390-tools, screen, systemd, and xorg-x11-server), and Ubuntu (godot, golang-1.22, libblockdev, node-express, pam, samba, and udisks2).

Inside this week's LWN.net Weekly Edition:

• Front: GNOME a11y; hierarchical scheduler; CoMaps; GPU restore; FAIR.pm; buffered I/O writeback; NFS; Lustre
• Briefs: Rocky Linux 10.0; Git 2.50; KDE Plasma 6.4; Kubernetes Slack; Radicle Desktop; Quote; ...
• Announcements: Newsletters, conferences, security updates, patches, and more.

The POSIX realtime model, which is implemented in the Linux kernel, can ensure that a realtime process obtains the CPU time it needs to get its job done. It can be less effective, though, when there are multiple realtime processes competing for the available CPU resources. The hierarchical constant bandwidth server patch series, posted by Yuri Andriaccio with work by Luca Abeni, Alessio Balsini, and Andrea Parri, is a modification to the Linux scheduler intended to make it possible to configure systems with multiple realtime tasks in a deterministic and correct manner.

The Lustre filesystem has a long history, some of which intersects with Linux. It was added to the staging tree in 2013, but was bounced out of staging in 2018, due to a lack of progress and a development model that was incompatible with the kernel's. Lustre may be working its way back into the kernel, though. In a filesystem-track session at the 2025 Linux Storage, Filesystem, Memory Management, and BPF Summit (LSFMM+BPF), Timothy Day and James Simmons led a discussion on how to get Lustre into the mainline.

The KDE Project has announced the Plasma 6.4 release. New features include more flexible tiling features, improvements to the Spectacle screen capture utility, a number of accessibility enhancements, and much more. See the changelog for a complete list of new features, enhancements, and bug fixes.

Security updates have been issued by Debian (gst-plugins-bad1.0, konsole, and libblockdev), Oracle (buildah, containernetworking-plugins, gimp, git-lfs, gvisor-tap-vsock, kernel, libvpx, podman, and skopeo), Red Hat (apache-commons-beanutils and thunderbird), Slackware (xorg), SUSE (gdm, golang-github-prometheus-alertmanager, golang-github-prometheus-node_exporter, golang-github-prometheus-prometheus, govulncheck-vulndb, grafana, kernel, Multi-Linux Manager, Multi-Linux Manager Client Tools, openssl-3, pam, python-cryptography, python-requests, python-setuptools, python3-requests, SUSE Manager Server, systemd, ucode-intel, xorg-x11-server, and xwayland), and Ubuntu (dwarfutils, mujs, node-katex, xorg-server, xorg-server-hwe-16.04, xorg-server-hwe-18.04, and xorg-server, xwayland).

The fundamental concept of checkpoint/restore is elegant: capture a process's state and resurrect it later, perhaps elsewhere. Checkpointing meticulously records a process's memory, open files, CPU state, and more into a snapshot. Restoration then reconstructs the process from this state. This established technique faces new challenges with GPU-accelerated applications, where low-latency restoration is crucial for fault tolerance, live migration, and fast startups. Recently, the restore process for AMD GPUs has been redesigned to eliminate substantial bottlenecks.

Accessibility features and the work that goes into developing those features often tend to be overlooked and are poorly understood by all but the people who actually depend on such features. At Fedora's annual developer conference, Flock, Lukáš Tyrychtr sought to improve understanding and raise awareness about accessibility with his session on accessibility barriers and screen-reader functionality in GNOME. His talk provided rare insight into the world of using and developing open-source software for visually-impaired users—including landing important accessibility improvements in the latest GNOME release.

Security updates have been issued by AlmaLinux (.NET 8.0, .NET 9.0, buildah, containernetworking-plugins, firefox, gstreamer1-plugins-bad-free, libsoup3, podman, skopeo, sqlite, thunderbird, unbound, valkey, varnish, and xz), Debian (webkit2gtk), Fedora (fido-device-onboard, python-django4.2, rust-git-interactive-rebase-tool, and thunderbird), Red Hat (libsoup), Slackware (libxml2), SUSE (java-11-openjdk, kernel, and wireshark), and Ubuntu (c3p0, dojo, python-django, python3.13, python3.12, python3.11, python3.10, python3.9, python3.8, python3.7, python3.6, and requests).

The Kubernetes project has announced that it will be losing its "special status" with the Slack communication platform and will be downgraded to the free tier in a matter of days:

On Friday, June 20, we will be subject to the feature limitations of free Slack. The primary ones which will affect us will be only retaining 90 days of history, and having to disable several apps and workflows which we are currently using. The Slack Admin team will do their best to manage these limitations.

The project has a FAQ covering the change, its impacts, and more. The CNCF projects staff has proposed a move to the Discord service as the best option to handle the more than 200,000 users and thousands of posts per day from the Kubernetes community. The Kubernetes Steering Committee will be making its decision "in the next few weeks".

Version 2.50.0 of the Git source-code management system has been released with a long list of new user features, performance improvements, and bug fixes. See the announcement and this GitHub blog post for details.

At the 2025 Linux Storage, Filesystem, Memory Management, and BPF Summit (LSFMM+BPF), Anna Schumaker led a discussion about implementing the NFS v4.2 WRITE_SAME command in both the NFS client and server. WRITE_SAME is meant to write large amounts of identical data (e.g. zeroes) to the server without actually needing to transfer all of it over the wire. In her topic proposal, Schumaker wondered whether other filesystems needed the functionality, so that it should be implemented at the virtual filesystem (VFS) layer, or whether it should simply be handled as an NFS-specific ioctl().

Security updates have been issued by AlmaLinux (.NET 8.0 and .NET 9.0), Arch Linux (curl, ghostscript, go, konsole, python-django, roundcubemail, and samba), Fedora (aerc, chromium, golang-x-perf, libkrun, python3.11, python3.12, rust-kbs-types, rust-sev, rust-sevctl, valkey, and wireshark), Gentoo (Konsole and sysstat), Oracle (.NET 9.0), Red Hat (bootc, grub2, keylime-agent-rust, python3.12-cryptography, rpm-ostree, rust-bootupd, xorg-x11-server, and xorg-x11-server-Xwayland), SUSE (apache2-mod_auth_openidc, docker, grub2, java-1_8_0-openj9, kernel, less, python-Django, screen, and sqlite3), and Ubuntu (cifs-utils and modsecurity-apache).