Linux Weekly News

At the end of January we ran this article on the discussions around a set of Rust bindings for the kernel's DMA-mapping layer. Many pixels have been expended on the topic since across the net, most recently in this sprawling email thread. Linus Torvalds has now made his feelings known on the topic:

You are not forced to take any Rust code, or care about any Rust code in the DMA code. You can ignore it.

But "ignore the Rust side" automatically also means that you don't have any *say* on the Rust side.

You can't have it both ways. You can't say "I want to have nothing to do with Rust", and then in the very next sentence say "And that means that the Rust code that I will ignore cannot use the C interfaces I maintain".

The code in question seems highly likely to be merged for the 6.15 release.

Version 1.85.0 of the Rust language has been released. Changes in the release include support for async closures, some convenience iterators for tuples, and a number of stabilized APIs. The headline feature, though, is that this release stabilizes the Rust 2024 edition, described as "the largest edition we have released". The 2024 edition guide has a detailed listing of all the changes that were incorporated this time around.

The maximum filesystem block size that the kernel can support has always been limited by the host page size for Linux, even if the filesystems could handle larger block sizes. The large-block-size (LBS) patches that were merged for the 6.12 kernel removed this limitation in XFS, thereby decoupling the page size from the filesystem block size. XFS is the first filesystem to gain this support, with other filesystems likely to add LBS support in the future. In addition, the LBS patches have been used to get the initial atomic-write support into XFS.

Atomic block writes, which have been discussed here a few times in the past, are block operations that either complete fully or do not occur at all, ensuring data consistency and preventing partial (or "torn") writes. This means the disk will, at all times, contain either the complete new data from the atomic write operation or the complete old data from a previous write. It will never have a mix of both the old and the new data, even if a power failure occurs during an ongoing atomic write operation. Atomic writes have been of interest to many Linux users, particularly database developers, as this feature can provide significant performance improvements.

Security updates have been issued by Debian (mosquitto), Fedora (gnutls, kernel, libtasn1, microcode_ctl, openssh, python3.10, python3.11, and python3.9), Red Hat (bind, bind9.16, buildah, container-tools:rhel8, podman, and redis:6), Slackware (libxml2), SUSE (dcmtk, google-osconfig-agent, java-17-openj9, kubernetes1.30-apiserver, kubernetes1.31-apiserver, openssh, and ruby3.4-rubygem-grpc), and Ubuntu (linux, linux-lowlatency and linux-aws, linux-azure, linux-gcp, linux-oracle, linux-raspi, linux-realtime).

Inside this week's LWN.net Weekly Edition:

• Front: Systemd; AI scraperbots; Time-slice extension; FUSE regression; Multi-size THPs; Memcached; Meshtastic.
• Briefs: Asahi leadership; Debian images; RISC-V Fedora; OpenSUSE; Mesa 25.0.0; Pi-hole v6; Quotes; ...
• Announcements: Newsletters, conferences, security updates, patches, and more.

Mark Surman, president of the Mozilla Corporation, has announced leadership updates for Mozilla. This includes a Mozilla Leadership Council made up of executives from each Mozilla organization, and new board chairs for the not-for-profit Mozilla Foundation, the Mozilla Corporation, and Mozilla.ai. The announcement also indicates a desire to further "diversify" Mozilla's focus:

We've recognized that Mozilla faces major headwinds in terms of both financial growth and mission impact. While Firefox remains the core of what we do, we also need to take steps to diversify: investing in privacy-respecting advertising to grow new revenue in the near term; developing trustworthy, open source AI to ensure technical and product relevance in the mid term; and creating online fundraising campaigns that will draw a bigger circle of supporters over the long run. Mozilla's impact and survival depend on us simultaneously strengthening Firefox AND finding new sources of revenue AND manifesting our mission in fresh ways. That is why we're working hard on all of these fronts.

Steven Rostedt recently posted a patch set that could help improve the performance of certain user-space applications by giving the scheduler more context about when they are safe to interrupt. The patch set lets programs request a small grace window before they can be interrupted so that they can relinquish any locks, decreasing the amount of time that other threads have to spend waiting. Rostedt shared performance numbers suggesting that the patch might cut the amount of time spent acquiring locks in half for some programs — although, since his test was specifically tuned for this case, real-world projects should expect a somewhat less dramatic improvement. The change received some pushback from scheduler maintainer Peter Zijlstra, who objected to the patch set's approach.

Version 25.0.0 of the Mesa graphics library has been released. "The flashiest addition is probably the support for Vulkan 1.4 by Anv (Intel), Asahi (Apple), Lavapipe (software), NVK (NVIDIA), PanVK (Mali), RADV (AMD), and Turnip (Qualcomm). Users can expect the usual flurry of improvements across all drivers and components."

Many of us enjoy uninterrupted access to mobile networks. However, in remote areas or during emergencies, that connectivity may not always be available. For such scenarios, Meshtastic offers a decentralized wireless mesh network with open-source firmware that runs on affordable, low-power devices. At FOSDEM 2025, the Meshtastic project was represented by one of its core developers, Thomas Göttgens, who gave a talk, "Meshtastic - off-grid communication for everyone", in the Radio developer room (devroom).

The Fedora Project has announced two milestones in its journey to supporting the RISC-V architecture: a dedicated RISC-V Koji build system instance is live in the Fedora data center, and Fedora 41-based images are now available for RISC-V. It is also possible to run Fedora RISC-V images using QEMU for those without supported hardware.

Debian Developer Thomas Lange has written a blog post in the attempt to help users find the right Debian image for their systems.

It's difficult to find the right Debian image. We have thousands of ISO files and cloud images and we support multiple CPU architectures and several download methods. The directory structure of our main image server is like a maze, and our web pages for downloading are also confusing.

Security updates have been issued by AlmaLinux (gcc-toolset-14-gcc, nodejs:18, and nodejs:22), Fedora (bootc), Gentoo (OpenSSH), Oracle (doxygen, libxml2, mingw-glib2, and NetworkManager), Red Hat (bind, bind9.16, bind9.18, kernel, kernel-rt, mysql, and mysql:8.0), Slackware (openssh), SUSE (buildah, emacs, glibc, google-osconfig-agent, grub2, java-11-openj9, kernel, netty, netty-tcnative, openssh, openvswitch, podman, and ucode-intel), and Ubuntu (atril, libsndfile, libtasn1-6, openssh, python-virtualenv, and symfony).

Pi-hole v6 has been released. The latest version of the popular ad-blocking software sports a redesigned user interface, has support for subscribing to allowlists, and brings a new REST API and embedded web server. Its Docker/OCI image is now based on Alpine Linux rather than Debian to reduce image size. See the announcement for guidance on upgrading existing Pi-hole installations.

The Reproducible-openSUSE project has announced that it has created a usable version of openSUSE with 100% reproducible packages.

[Bernhard] Wiedemann took on this 4-month-long project to create a fork of openSUSE that has 100% bit-reproducible packages. So far ring0 (aka bootstrap) and ring1 with 3,300 software packages have all successfully been patched and tested.

This build is not yet recommended for production use, though.

Kernel developers have been working to convert various internal interfaces to use folios; while this process has been progressing, there is still the occasional regression introduced by the change. In December 2024, it was discovered that installing a Flatpak application could trigger a filesystem bug in the kernel that would cause the software to read incorrect data from the disk. The problem was quickly fixed — only for an another problem caused by the folio rewrite to pop up in the same kernel subsystem. This was discovered by an Arch Linux user, who noticed that selecting files in a Flatpak application was causing kernel crashes. Now both bugs are fixed, but there may be more bugs to find.

The 6.12.15 stable kernel update has been fast-tracked to release. It seems that its predecessor contains a regression in the XFS filesystem that can lead to kernel crashes.

Security updates have been issued by Debian (gnutls28, openssh, and pam-pkcs11), Mageia (microcode and python-cryptography), Oracle (nodejs:18, nodejs:20, and rsync), Red Hat (gcc, nodejs:20, and nodejs:22), SUSE (emacs, kernel, openvswitch, and ucode-intel), and Ubuntu (Docker).

It is a standard practice to use milestones to reflect on the achievements of a project, such as the anniversary of its first release or first commit. Usually, these are observed at five and ten‑year increments; the tenth anniversary of the 1.0 release, or 25 years since from the first public announcement, etc. Lennart Poettering, however, took a different approach at FOSDEM 2025 with a keynote commemorating 14 years of systemd, and a brief look ahead at his goals and systemd's challenges for the future.

Greg Kroah-Hartman has released three more stable kernels: 6.13.3, 6.12.14, and 6.6.78. There was a bit of confusion that resulted in the patch for CVE 2025-21687 getting applied twice — but that doesn't result in any problems for users of the kernel, just a bit of extra noise in the CVE database, so Kroah-Hartman has decided to leave the releases as-is instead of rushing another point release.