Greg Kroah-Hartman has released seven new stable kernels: 6.9.10, 6.6.41, 6.1.100, 5.15.163, 5.10.222, 5.4.280, and 4.19.318. As usual, each contains important fixes throughout the kernel tree.

Leah Rumancik led a filesystem-track session at the 2024 Linux Storage, Filesystem, Memory Management, and BPF Summit on the testing needed to qualify XFS patches for the stable kernels. At last year's summit, Rumancik, Amir Goldstein, and Chandan Babu Rajendra presented on their efforts to test and backport fixes for the XFS filesystem to three separate stable kernels. There has been some longstanding unhappiness in the XFS-development community with the stable-kernel process, which led to backports ceasing for that filesystem until Goldstein started working on XFS testing for the stable trees a few years ago. In this year's session, Rumancik updated attendees on how things had gone over the last year and wanted to discuss some remaining pain points for the process.

Security updates have been issued by Debian (chromium), Fedora (freeradius), Red Hat (firefox, java-1.8.0-openjdk, and java-17-openjdk), Slackware (openssl), SUSE (ghostscript, gnutls, podman, and python-Django), and Ubuntu (linux-hwe-6.5, linux-ibm-5.15, linux-lowlatency, linux-lowlatency-hwe-5.15, linux-oracle-5.15, linux-oracle, linux-xilinx-zynqmp, and stunnel).

Maintenance of the kernel is a difficult, often thankless, task; how it is being handled, the role of maintainers, burnout, and so on are recurring topics at kernel-related conferences. At the 2024 Linux Storage, Filesystem, Memory Management, and BPF Summit, Josef Bacik and Christian Brauner led a session to discuss possible changes to the way filesystems are maintained, though Bacik took the lead role (and the podium). There are a number of interrelated topics, including merging new filesystems, removing old ones, making and testing changes throughout the filesystem tree, and more.

Amir Goldstein led a filesystem-track session at the 2024 Linux Storage, Filesystem, Memory Management, and BPF Summit on his project to build a hierarchical storage management (HSM) system using fanotify. The idea is to monitor file access in order to determine when to retrieve content from non-local storage (e.g. the cloud). The session was a follow-up to last year's introduction to the project, which covered some of the problems he had encountered; this year, he was updating attendees on its status and progress, along with some other problem areas that he wanted to discuss.

Greg Kroah-Hartman has released the 6.6.40 and 6.1.99 stable kernels. Both contain a fix for the USB subsystem; anyone who uses those kernel series and "the XHCI USB host controller driver (i.e. USB 3) must upgrade".

Security updates have been issued by Fedora (cups, krb5, pgadmin4, python3.6, and yarnpkg), Mageia (freeradius, kernel, kmod-xtables-addons, kmod-virtualbox, and dwarves, kernel-linus, and squid), Red Hat (ghostscript, kernel, and less), SUSE (avahi, c-ares, cairo, cups, fdo-client, gdk-pixbuf, git, libarchive, openvswitch3, podman, polkit, python-black, python-Jinja2, python-urllib3, skopeo, squashfs, tiff, traceroute, and wget), and Ubuntu (linux, linux-azure, linux-azure-5.4, linux-bluefield, linux-gcp, linux-gcp-5.4, linux-gkeop, linux-ibm, linux-ibm-5.4, linux-kvm).

The 6.9.9, 6.6.39, and 6.1.98 stable kernels have been released. As usual, they contain lots of important fixes throughout the tree.

Security updates have been issued by AlmaLinux (dotnet6.0, dotnet8.0, fence-agents, and virt:rhel and virt-devel:rhel), Debian (exim4 and firefox-esr), Fedora (dotnet8.0, firefox, onnx, qt6-qtbase, squid, and wordpress), Mageia (golang, netatalk, php, and poppler), Red Hat (ghostscript, httpd, openssh, python3, and ruby), Slackware (mozilla), SUSE (kernel and openssh), and Ubuntu (linux-aws-5.4, linux-azure, linux-ibm-5.15, and python3.5, python3.6, python3.7, python3.8, python3.9, python3.10, python3.11, python3.12).

The eventfs filesystem provides an interface to the tracepoints that are available to be used by various Linux tracing tools (e.g. ftrace, perf, uprobes, etc.); it is meant to be a version of the tracefs filesystem that dynamically allocates its entries as needed. The goal is to reduce the memory required for multiple instances of tracefs, as Steven Rostedt described in a session at the 2022 Linux Storage, Filesystem, Memory Management, and BPF Summit. He returned to the 2024 edition of the summit to talk further about how to make pseudo (or virtual) filesystems, such as tracefs/eventfs, more like regular Linux filesystems, where the directory entries (dentries) and inodes are only created (and cached) as needed.

Sxmo, short for "Simple X Mobile", is described on its web site as "a minimalist environment for Linux mobile devices"; it offers a menu-driven interface that is controlled with the phone's hardware buttons. Sxmo enables the user to send SMS messages from a text editor and is entirely customizable with shell scripts. This peculiar mobile user interface significantly differs from the prevailing approach—but it works.

There are a number of kernel filesystems that store their directory entries directly in the directory-entry cache (dcache) without having any permanent storage for those objects. It started out as a "neat hack" for ramfs, Al Viro said, at the start of his filesystem-track session at the 2024 Linux Storage, Filesystem, Memory Management, and BPF Summit. Unfortunately, as the use of this technique has grown into other filesystems, there has been a lot of scope creep that has gotten out of control. He wanted to discuss some new infrastructure that he is working on to try to clean some of that up.

On his blog, Behdad Esfahbod has published a lengthy and detailed look at the state of open-source text rendering. It looks at the libraries available, application support, future directions, and gives a summary analysis of the ecosystem.

In broad strokes, OpenType added support for color fonts, variable fonts, and the Universal Shaping Engine. The Free & Open Source stack supports all of these advances at the lower level, but application UI support has been slower to arrive. The Open Source text stack also gained enormous market-share when Android and Google Chrome fully embraced it.

Looking forward, there is a Rust migration of the text stack underway, which will unify font compilation and consumption under a safe programming language. Incremental Font Transfer will enable streaming fonts to web browsers. And my proposed Wasm-fonts will enable more expressive fonts.

Security updates have been issued by AlmaLinux (openssh), Debian (krb5), Fedora (yt-dlp), Gentoo (firefox, KDE Plasma Workspaces, Stellarium, thunderbird, and X.Org X11 library), Mageia (python-js2py and znc), Oracle (389-ds, c-ares, container-tools, cups, go-toolset, httpd:2.4/httpd, iperf3, kernel, less, libreoffice, libuv, nghttp2, openldap, openssh, python-idna, python-jinja2, python-pillow, python3, python3.11-PyMySQL, and xmlrpc-c), Red Hat (kernel, kernel-rt, openssh, and virt:rhel and virt-devel:rhel modules), and SUSE (go1.21, go1.22, krb5, kubevirt, virt-api-container, virt-controller-container, virt-exportproxy-container, virt-exportserver-container, virt-handler-container, virt-launcher-container, virt-libguestfs-t, netty3, opera, and python-urllib3).

Security updates have been issued by AlmaLinux (389-ds, c-ares, container-tools, cups, fontforge, go-toolset, iperf3, less, libreoffice, libuv, nghttp2, openldap, python-idna, python-jinja2, python-pillow, python3, python3.11-PyMySQL, qemu-kvm, and xmlrpc-c), Debian (znc), Fedora (firmitas and libnbd), Mageia (dcmtk, krb5, libcdio, and openssh), Oracle (golang, openssh, pki-core, and qemu-kvm), Red Hat (openssh), SUSE (apache2-mod_auth_openidc, emacs, go1.21, go1.22, krb5, openCryptoki, and openssh), and Ubuntu (linux, linux-aws, linux-aws-hwe, linux-gcp, linux-gcp-4.15, linux-hwe, linux-kvm, linux-oracle, linux, linux-aws, linux-azure, linux-azure-5.4, linux-bluefield, linux-gcp, 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-kvm, linux-lts-xenial, linux, linux-gcp, linux-gcp-6.5, linux-laptop, linux-nvidia-6.5, linux-raspi, linux, linux-gcp, linux-lowlatency, linux-lowlatency-hwe-5.15, linux-nvidia, linux-xilinx-zynqmp, linux, linux-ibm, linux-lowlatency, linux-nvidia, linux-raspi, linux-aws, linux-aws-6.5, linux-oem-6.5, linux-oracle, linux-oracle-6.5, linux-starfive, linux-aws, linux-azure, linux-azure-5.15, linux-azure-fde, linux-azure-fde-5.15, linux-gke, linux-gkeop, linux-gkeop-5.15, linux-ibm, linux-intel-iotg, linux-intel-iotg-5.15, linux-kvm, linux-oracle, linux-oracle-5.15, linux-azure, linux-azure, linux-azure-6.5, linux-bluefield, linux-iot, linux-gcp, linux-intel, linux-hwe-5.15, and php7.0 and php7.2).

There are a handful of extensions to the "new" mount API that Christian Brauner wanted to discuss as part of a filesystem session at the 2024 Linux Storage, Filesystem, Memory Management, and BPF Summit. In the session, though, the only one that he got to was a followup to last year's discussion on mount-operation monitoring. There is a need for user-space programs to be able to follow mount operations (e.g. mount and unmount) that happen in the system, especially for tools like container managers or systemd.

In 2016, Oliver Smith reached a point of frustration with the short lifespan of updates for his Android phone. Taking matters into his own hands, he began developing postmarketOS, a Linux distribution for mobile phones. Eight years later, the core team and trusted contributors have grown to twenty individuals, while the latest release, v24.06, now shows support for over 250 devices. Although postmarketOS isn't usable as a day-to-day phone operating system on all of them, it can also enable repurposing devices into compact servers or kiosk machines.

Eric Sandeen led a filesystem-track session at the 2024 Linux Storage, Filesystem, Memory Management, and BPF Summit on completing the conversion of the existing kernel filesystems to use the mount API that was added for the 5.2 kernel in 2019. That API is invariably called the "new" API, which it is when compared to the venerable mount() system call, but it has been available for five years or so at this point without really pushing its predecessor aside. Sandeen wanted to discuss the status of the conversion process and some other questions surrounding the new API.

Security updates have been issued by AlmaLinux (ipa and libreswan), Debian (netty), Fedora (python-PyMySQL, tomcat, and webkitgtk), Gentoo (Flatpak, GLib, JHead, LZ4, and RDoc), Mageia (thunderbird), Oracle (nghttp2 and thunderbird), Red Hat (dnsmasq, libreswan, pki-core, and python3.11), Slackware (emacs), SUSE (gnome-settings-daemon, libarchive, qpdf, vte, and wget), and Ubuntu (libhibernate3-java).