Linux Weekly News

Inside this week's LWN.net Weekly Edition:

• Front: FUSE performance; Magic kfuncs; Tails Linux; Direct I/O and modifying buffers; Working with bootable containers.
• Briefs: Kernel LLM policy; Firefox 145; FHS; Homebrew 5.0.0; Mastodon 4.5; Public-inbox 2.0.0; Pytest 9.0.0; Quote; ...
• Announcements: Newsletters, conferences, security updates, patches, and more.

Version 5.0.0 of the Homebrew package manager for Linux and macOS has been released. Notable changes in this release include download concurrency by default, official support for 64-bit Arm on Linux, and more.

Longtime LWN readers will have encountered the concept of "stable pages" before; it was first covered here nearly 15 years ago. For the most part, the problem that stable pages were meant to solve — preventing errors when user space modifies a buffer that is under I/O — has been dealt with. But recent discussions show that there is one area where problems remain: direct I/O. There is some disagreement, though, over whether those problems are the result of user-space bugs and how much of a performance price should be paid to address them.

Security updates have been issued by AlmaLinux (kernel, kernel-rt, and libtiff), Debian (kernel, libarchive, rust-sudo-rs, and squid), Fedora (chromium, dotnet8.0, forgejo, ruby, and webkitgtk), Oracle (bind, bind9.18, kernel, kernel-uek*, libtiff, and runc), Red Hat (firefox, kernel, and kernel-rt), Slackware (mozilla), SUSE (buildah, colord, containerd, kernel, lasso, libsoup, micropython, ongres-scram, openssh, proxy-helm, uyuni-tools, python-pdfminer.six, qatengine, qatlib, regclient, and runc), and Ubuntu (raptor and raptor2).

Firefox 145 has been released. Notable changes in this release include note-taking features for PDFs viewed in Firefox, enhanced privacy protections, and the ability to access and manage passwords in the sidebar. This release also drops support for 32-bit Linux systems.

Tails is an unusual Linux distribution developed by the Tor Project; it is designed to help users work around internet censorship and avoid surveillance. It is a "portable" operating system that is meant to be run from a USB stick or ISO image and to leave no trace on the computer it was run on. Tails routes connections to the internet over the Tor network and includes a selection of applications and tools suited to working with sensitive documents, communicating securely, and preserving users' anonymity. The tradeoff, of course, is that Tails is less convenient and requires users to learn a new set of tools to avoid compromising their own security and anonymity. Tails 7.1 was released in October, and it seemed like as good a time as any to take it for a spin.

Security updates have been issued by AlmaLinux (bind, expat, kernel, osbuild-composer, qt6-qtsvg, runc, valkey, and xorg-x11-server-Xwayland), Debian (incus), Fedora (cef and dotnet8.0), Mageia (strongswan), Red Hat (fence-agents and python-requests), SUSE (chromium, colord, erlang26, java-1_8_0-openjdk, libsoup, python-django, thunderbird, tiff, and warewulf4), and Ubuntu (intel-microcode and rust-sudo-rs).

Version 2.0.0 of public-inbox, the mail archiving system behind lore.kernel.org and LWN's email archive, has been released. "This release includes several new features and fixes; mostly around improved integration between inboxes and coderepos for solver. Portability and reliability is also improved, especially in the internal process management of lei."

When programs written in BPF (the kernel's hot-loadable virtual-machine bytecode) call kernel functions (kfuncs), it may be useful for those functions to have additional information about the context in which those BPF programs are executing. Rather than requiring it to supply that information, it would be convenient to let the BPF verifier pass that information to the called function automatically. That is already possible, but a recent patch set from Ihor Solodrai would make it more ergonomic. It allows kernel developers to specify that a kfunc should be passed additional parameters inferred by the verifier, invisibly to the BPF program. The discussion included concerns that Solodrai's implementation was unnecessarily complex, however.

Version 9.0.0 of pytest has been released. Notable changes in this release include the addition of subtests, native support for TOML configuration files, and a new strict mode. See the changelog for a complete list of new features, enhancements, and bug fixes.

Security updates have been issued by AlmaLinux (galera and mariadb, kernel, kernel-rt, mingw-libtiff, redis:7, tigervnc, and xorg-x11-server-Xwayland), Fedora (bind, bind-dyndb-ldap, bpfman, chromium, dolphin-emu, dotnet9.0, golang-github-openprinting-ipp-usb, kea, libnbd, luksmeta, python-cloudpickle, python-pydantic, python-pydantic-core, python-uv-build, ruby, ruff, rust-get-size-derive2, rust-get-size2, rust-regex, rust-regex-automata, rust-reqsign, rust-reqsign-aws-v4, rust-reqsign-command-execute-tokio, rust-reqsign-core, rust-reqsign-file-read-tokio, rust-reqsign-http-send-reqwest, singularity-ce, uv, xen, and xorg-x11-server-Xwayland), Mageia (libxml2, libxslt, opencontainers-runc, and xen), Oracle (bind, galera and mariadb, libsoup, linux-firmware, mariadb:10.5, mingw-libtiff, osbuild-composer, qt5-qt3d, tigervnc, and xorg-x11-server-Xwayland), SUSE (chromium, erlang, google-osconfig-agent, govulncheck-vulndb, java-11-openjdk, java-17-openjdk, java-1_8_0-openj9, opentofu, python-djangorestframework-simplejwt, python311-Django, python315, squid, thunderbird, tiff, tomcat, tomcat11, and xen), and Ubuntu (linux-fips, linux-hwe-6.14, and linux-nvidia-tegra, linux-nvidia-tegra-5.15, linux-nvidia-tegra-igx, linux-raspi).

The 6.18-rc5 kernel prepatch is out for testing. "In other words: it all looks just the way I like it at this point: small and boring."

The KeePassXC project has recently updated its contribution policy and README to note its policy around contributions created with generative AI tools. The project's use of those tools, such as GitHub Copilot, have raised a number of questions and concerns, which the project has responded to:

There are no AI features inside KeePassXC and there never will be!

The use of Copilot for drafting pull requests is reserved for very simple and focused tasks with a small handful of changes, such as simple bugfixes or UI changes. We use it sparingly (mostly because it's not very good at complex tasks) and only where we think it offers a benefit. Copilot is good at helping developers plan complex changes by reviewing the code base and writing suggestions in markdown, as well as boilerplate tasks such as test development. Copilot can mess up, and we catch that in our standard review process (e.g., by committing a full directory of rubbish, which we identified and fixed). You can review our copilot instructions. Would we ever let AI rewrite our crypto stack? No. Would we let it refactor and rewrite large parts of the application? No. Would we ask it to fix a regression or add more test cases? Yes, sometimes.

Emphasis in the original. See the full post to learn more about the project's processes and pull requests that have been created with AI assistance.

The kernel community is currently reviewing a proposed policy for contributors who are using large language models to assist in the creation of their patches; the primary focus is on disclosure of the use of those tools. "The goal here is to clarify community expectations around tools. This lets everyone become more productive while also maintaining high degrees of trust between submitters and reviewers."

The bootc project allows users to create a bootable Linux system image using the container tooling that many developers are already familiar with. It is an evolution of OSTree (now called libostree), which is used to create Fedora Silverblue and other image-based distributions. While creating custom images is still a job for experts, the container technology simplifies delivering heavily customized images to non-technical users.

Security updates have been issued by AlmaLinux (bind, bind9.16, libsoup, mariadb:10.5, and sssd), Debian (chromium, keystone, and swift), Fedora (apptainer, buildah, chromium, fcitx5, fcitx5-anthy, fcitx5-chewing, fcitx5-chinese-addons, fcitx5-configtool, fcitx5-hangul, fcitx5-kkc, fcitx5-libthai, fcitx5-m17n, fcitx5-qt, fcitx5-rime, fcitx5-sayura, fcitx5-skk, fcitx5-table-extra, fcitx5-unikey, fcitx5-zhuyin, GeographicLib, libime, mbedtls, mingw-poppler, mupen64plus, python-starlette, webkitgtk, and xen), Mageia (dcmtk, java-1.8.0-openjdk, java-11-openjdk, java-17-openjdk, java-latest-openjdk, libvpx, and sqlite3), Oracle (bind, bind9.16, kernel, libsoup, libsoup3, osbuild-composer, qt6-qtsvg, sssd, and valkey), Red Hat (kernel and kernel-rt), SUSE (bind, gpg2, ImageMagick, python-Django, and runc), and Ubuntu (linux-azure, linux-azure-4.15, linux-fips, linux-aws-fips, inux-gcp-fips, linux-gcp, linux-gcp-6.8, linux-gke, linux-intel-iot-realtime, linux-realtime, linux-raspi-5.4, and linux-realtime, linux-realtime-6.8).

Version 4.5 of the Mastodon decentralized social-media platform has been released. Notable features in this release include quote posts, native emoji support, as well as enhanced moderation and blocking features for server administrators. The project also has a post detailing new features in 4.5 for developers of clients and other software that interacts with Mastodon.

The future of the Filesystem Hierarchy Standard (FHS) has been under discussion for some time; now, Neal Gompa has announced that the FHS is "hosted and stewarded" by Freedesktop.org.

For those who are unaware, the Filesystem Hierarchy Standard (FHS) is the definition for POSIX operating systems to organize system and user data. It is broadly adopted by Linux, BSD, and other operating systems that follow POSIX-like conventions.

See this page for the specification's new home.

Filesystems are complex and performance-sensitive beasts. They can also present security concerns. Microkernel-based systems have long pushed filesystems into separate processes in order to contain any vulnerabilities that may be found there. Linux can do the same with the Filesystem in Userspace (FUSE) subsystem, but using FUSE brings a significant performance penalty. Darrick Wong is working on ways to eliminate that penalty, and he has a massive patch set showing how ext4 filesystems can be safely implemented in user space by unprivileged processes with good performance. This work has the potential to radically change how filesystems are managed on Linux systems.

Security updates have been issued by Debian (unbound), Fedora (deepin-qt5integration, deepin-qt5platform-plugins, dtkcore, dtkgui, dtklog, dtkwidget, fcitx-qt5, fcitx5-qt, fontforge, gammaray, golang-github-openprinting-ipp-usb, kddockwidgets, keepassxc, kf5-akonadi-server, kf5-frameworkintegration, kf5-kwayland, plasma-integration, python-qt5, qadwaitadecorations, qt5, qt5-qt3d, qt5-qtbase, qt5-qtcharts, qt5-qtconnectivity, qt5-qtdatavis3d, qt5-qtdeclarative, qt5-qtdoc, qt5-qtgamepad, qt5-qtgraphicaleffects, qt5-qtimageformats, qt5-qtlocation, qt5-qtmultimedia, qt5-qtnetworkauth, qt5-qtquickcontrols, qt5-qtquickcontrols2, qt5-qtremoteobjects, qt5-qtscript, qt5-qtscxml, qt5-qtsensors, qt5-qtserialbus, qt5-qtserialport, qt5-qtspeech, qt5-qtsvg, qt5-qttools, qt5-qttranslations, qt5-qtvirtualkeyboard, qt5-qtwayland, qt5-qtwebchannel, qt5-qtwebengine, qt5-qtwebkit, qt5-qtwebsockets, qt5-qtwebview, qt5-qtx11extras, qt5-qtxmlpatterns, qt5ct, and xorg-x11-server), Mageia (binutils, gstreamer1.0-plugins-bad, libsoup, libsoup3, mediawiki, net-tools, and tigervnc, x11-server, and x11-server-xwayland), Red Hat (tigervnc), SUSE (aws-efs-utils, fetchmail, flake-pilot, ImageMagick, java-1_8_0-ibm, java-1_8_0-openjdk, kernel-devel, kubecolor, OpenSMTPD, sccache, tiff, and zellij), and Ubuntu (linux, linux-aws, linux-aws-6.14, linux-gcp, linux-gcp-6.14, linux-oem-6.14, linux-oracle, linux-oracle-6.14, linux-raspi, linux-realtime, linux, linux-aws, linux-gkeop, linux-hwe-6.8, linux-ibm, linux-ibm-6.8, linux-lowlatency, linux-lowlatency-hwe-6.8, linux-nvidia, linux-nvidia-lowlatency, linux, linux-aws, linux-kvm, linux-lts-xenial, linux-oracle-6.8, linux-realtime-6.14, poppler, python-django, and various linux-* packages).