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Security updates have been issued by Debian (abseil, atop, jetty9, ruby-saml, tomcat10, trafficserver, xz-utils, and zfs-linux), Fedora (chromium, condor, containernetworking-plugins, cri-tools1.29, crosswords-puzzle-sets-xword-dl, exim, ghostscript, matrix-synapse, upx, varnish, and yarnpkg), Gentoo (XZ Utils), Mageia (augeas, corosync, nss & firefox, and thunderbird), Oracle (container-tools:ol8, firefox, freetype, and kernel), Red Hat (firefox), SUSE (chromium, gn, firefox-esr, go1.23-1.23.8, go1.24, go1.24-1.24.2, google-guest-agent, govulncheck-vulndb, gsl, python311-ecdsa, thunderbird, and webkit2gtk3), and Ubuntu (kamailio, libdbd-mysql-perl, linux-nvidia, linux-nvidia-6.8, and tomcat9).

Linus has released 6.15-rc1 and closed the merge window for this release. "As expected, this was one of the bigger merge windows, almost certainly just because we had some pent-up development due to the previous releases being impacted by the holiday season. That said, while it's bigger than normal, it's not some kind of record-breaking thing.". In the end, 12.633 non-merge changesets were pulled into the mainline during this merge window.

A typical cloud-computing host will share some of its memory with each guest that it runs. The host retains its access to that memory, though, meaning that it can readily dig through that memory in search of data that the guest would prefer to keep private. The guest_memfd subsystem removes (most of) the host's access to guest memory, making the guest's data more secure. In the memory-management track of the 2025 Linux Storage, Filesystem, Memory-Management, and BPF Summit, David Hildenbrand ran a discussion on the state and future of this feature.

Alistair Popple started his session at the 2025 Linux Storage, Filesystem, Memory-Management, and BPF Summit by proclaiming that ZONE_DEVICE is "the ugly stepchild" of the kernel's memory-management subsystem. Ugly or not, the ability to manage memory that is attached to a peripheral device rather than a CPU is increasingly important on current hardware. Popple hoped to cover some of the challenges with ZONE_DEVICE and find ways to make the stepchild a bit more attractive, if not bring it into the family entirely.

At last year's Linux Storage, Filesystem, Memory-Management, and BPF Summit (LSFMM+BPF), there was a discussion about atomic writes that was accompanied by patches to support the feature in the block layer, and for direct I/O on XFS. That work was merged, but another piece of that discussion concerned adding the feature for buffered I/O, in part because the PostgreSQL database currently has to jump through hoops to ensure that its writes are not "torn" (partially written) when there is an error or crash. Luis Chamberlain led a combined storage and filesystem track at this year's summit to revisit the idea of providing atomic (or untorn) writes for buffered I/O.

Yonghong Song brought a story about tracking down the cause of a strange verifier error message to the 2025 Linux Storage, Filesystem, Memory-Management, and BPF Summit. He then presented some possible ways to improve Clang's user experience for anyone running into the same class of error in the future. Toward the end of his allotted time, he also discussed the problems with optimizations that change the signature of functions — a problem that José Marchesi had also brought up in the previous session.

Security updates have been issued by AlmaLinux (firefox), Debian (atop and thunderbird), Fedora (webkitgtk), Mageia (microcode), Oracle (expat), SUSE (apparmor, assimp-devel, aws-efs-utils, expat, firefox, ghostscript, go1.23, gotosocial, govulncheck-vulndb, GraphicsMagick, headscale, libmozjs-128-0, libsaml-devel, openvpn, perl-Data-Entropy, and xz), and Ubuntu (gnupg2, kernel, linux-azure-fips, linux-iot, openvpn, ruby-saml, and xz-utils).

Address-space isolation may well be, as Brendan Jackman said at the beginning of his memory-management-track session at the 2025 Linux Storage, Filesystem, Memory-Management, and BPF Summit, "some security bullshit". But it also holds the potential to protect the kernel from a wide range of vulnerabilities, both known and unknown, while reducing the impact of existing mitigations. Implementing address-space isolation with reasonable performance, though, is going to require some significant changes. Jackman was there to get feedback from the memory-management community on how those changes should be implemented.

The kernel must often step through the page tables of one or more processes to carry out various operations. This "page-table walking" tends to be performed by ad-hoc (duplicated) code all over the kernel. Oscar Salvador used a memory-management-track session at the 2025 Linux Storage, Filesystem, Memory-Management, and BPF Summit to talk about strategies to unify the kernel's page-table walking code just a little bit by making hugetlb pages look more like ordinary pages.

Version 1.86.0 of the Rust language has been released. Changes include support for trait upcasting, the ability to index multiple elements of HashMaps and slices mutably, and a number of stabilized APIs.

Security updates have been issued by AlmaLinux (expat), Debian (chromium, commons-vfs, firefox-esr, php-horde-editor, php-horde-imp, and thunderbird), Fedora (corosync, firefox, nextcloud, and suricata), Mageia (curl and upx), Oracle (emacs, fence-agents, freetype, kernel, libreoffice, libxml2, nginx:1.24, podman, python-jinja2, and tigervnc), Red Hat (firefox and python-jinja2), SUSE (assimp, ffmpeg-4, firefox, ghostscript, GraphicsMagick, libxslt, and tomcat), and Ubuntu (linux, linux-aws, linux-aws-5.15, linux-gcp, linux-gke, linux-gkeop, linux-ibm, linux-intel-iotg, linux-kvm, linux-lowlatency, linux-lowlatency-hwe-5.15, linux-meta-raspi, linux-nvidia-tegra, linux-oracle, linux-oracle-5.15, linux-raspi, linux, linux-azure, linux-azure-5.4, linux-bluefield, linux-gcp, linux-ibm, linux-kvm, linux-oracle, linux-oracle-5.4, linux-xilinx-zynqmp, linux-fips, linux-fips, linux-aws-fips, linux-gcp-fips, linux-hwe-5.15, and linux-realtime, linux-intel-iot-realtime).

Inside this week's LWN.net Weekly Edition:

• Front: Calibre 8.0; Fedora reproducibility; OpenWrt One; 6.15 Merge Window; LSFMM+BPF coverage including BPF in GCC, Rust merging process, and more.
• Briefs: Ubuntu namespaces; New FPL; PorteuX 2.0; Firefox 137.0; GCC Rust; Rockbox 4.0; Rust specification; Thundermail; Dave Täht RIP; Quotes; ...
• Announcements: Newsletters, conferences, security updates, patches, and more.

Saying that calibre is ebook-management software undersells the application by a fair margin. Calibre is an open-source Swiss Army knife for ebooks that can be used for everything from creating ebooks, converting ebooks from obscure formats to modern formats like EPUB, to serving up an ebook library over the web. The most recent major release, calibre 8.0, brings a better text-to-speech engine, a tool for creating audio overlays when authoring ebooks, support for profiles in the ebook viewer, and more.

José Marchesi and David Faust kicked off the BPF track at the 2025 Linux Storage, Filesystem, Memory-Management, and BPF Summit with an extra-long session on what they have been doing to support compiling to BPF in GCC. Overall, the project is slowly working toward full support for BPF, with most of the self-tests now passing using Faust's in-progress patches. However, the progress toward that goal has turned up a number of problems with how Clang supports BPF that needed to be discussed at length to find a path forward for both projects.

Ryan Sipes has announced efforts to expand Thunderbird's offerings with web services to "enhance the experience of using Thunderbird".

The Why for offering these services is simple. Thunderbird loses users each day to rich ecosystems that are both clients and services, such as Gmail and Office365. These ecosystems have both hard vendor lock-ins (through interoperability issues with 3rd-pary clients) and soft lock-ins (through convenience and integration between their clients and services). It is our goal to eventually have a similar offering so that a 100% open source, freedom-respecting alternative ecosystem is available for those who want it.

The planned services include hosted email, appointment scheduling, a revival of Firefox Send, and (of course) an AI assistant based on a partnership with Flower AI. The AI features will "always be optional for use by people who want them". Sipes is managing director of product for Thunderbird's parent organization, MZLA Technologies Corporation. LWN covered his GUADEC 2024 keynote last July.

Outgoing Fedora Project Leader (FPL) Matthew Miller has announced his successor, Jef Spaleta.

Some of you may remember Jef's passionate voice in the early Fedora community. He got involved all the way back in the days of fedora.us, before Red Hat got involved. Jef served on the Fedora Board from July 2007 through the end of 2008. This was the critical time after Fedora Extras and Fedora Core merged into one Fedora Linux where, with the launch of the "Features" process, Fedora became a truly community-led project.

Spaleta will be joining Red Hat full time in May and Miller will be formally handing off FPL duties at the Flock conference in June.

Version 2.0 of PorteuX, a distribution based on Slackware Linux, has been released. This release adds the ability to test experimental Wayland sessions for the Cinnamon, LXQt, and Xfce desktops. PorteuX 2.0 updates the Linux kernel to 6.14 and includes many package updates and bug fixes. Users have the choice of PorteuX stable or its rolling release called current. See the install.txt for instructions on installing PorteuX to disk.

The CPU's translation lookaside buffer (TLB) caches the results of virtual-address translations, significantly speeding memory accesses. TLB misses are expensive, so a lot of thought goes into using the TLB as efficiently as possible. Reducing pressure on the TLB was the topic of Rik van Riel's memory-management-track session at the 2025 Linux Storage, Filesystem, Memory-Management, and BPF Summit. Some approaches were considered, but the session was short on firm conclusions.

For those of you who still have dedicated audio players: version 4.0 of Rockbox, a replacement firmware for many players, has been released. This release brings support for a number of new devices, updated codecs, a number of user-interface improvements, some new games, and more. (LWN last reviewed Rockbox in 2010 — and looked at the ill-fated Android port that year as well).

Security updates have been issued by Debian (firefox-esr, jetty9, openjpeg2, and tomcat9), Fedora (dokuwiki, firefox, php-kissifrot-php-ixr, php-phpseclib3, and rust-zincati), Red Hat (kernel and pki-core), Slackware (mozilla), SUSE (apparmor, atop, docker, docker-stable, firefox, govulncheck-vulndb, libmodsecurity3, openvpn, upx, and warewulf4), and Ubuntu (inspircd, linux, linux-aws, linux-gcp, linux-gke, linux-gkeop, linux-ibm, linux-lowlatency, linux-lowlatency-hwe-6.8, linux-oem-6.8, linux-oracle, linux-oracle-6.8, linux-aws, linux-aws-5.4, linux-aws-fips, linux-azure-6.8, linux-hwe-6.8, linux-raspi, linux-realtime, nginx, phpseclib, and vim).