Security updates have been issued by AlmaLinux (mod_proxy_cluster), Debian (catdoc, chromium, nagvis, and sudo), Fedora (chromium, gum, kubernetes1.32, moodle, podman, python3-docs, python3.13, salt, and tigervnc), Mageia (x11-server, x11-server-xwayland & tigervnc), Oracle (apache-commons-beanutils, exiv2, expat, firefox, git, git-lfs, gstreamer1-plugins-bad-free, ipa, java-21-openjdk, kea, kernel, libarchive, libblockdev, libsoup3, libvpx, libxslt, mod_auth_openidc, nodejs22, osbuild-composer, perl, perl-File-Find-Rule, php, python-jinja2, python-tornado, sqlite, thunderbird, valkey, varnish, weldr-client, xorg-x11-server-Xwayland, xz, and yggdrasil), Red Hat (apache-commons-beanutils, javapackages-tools:201801, kernel, and python3.11), SUSE (apache-commons-fileupload, gimp, glib2, himmelblau, nvidia-open-driver-G06-signed, sqlite3, thunderbird, yelp, and yelp-xsl), and Ubuntu (samba).

The history of the bcachefs filesystem in the kernel has been turbulent, most recently with Linus Torvalds refusing a pull request for the 6.16-rc3 release. Torvalds has now pulled the code in question, but also said:

I think we'll be parting ways in the 6.17 merge window.

You made it very clear that I can't even question any bug-fixes and I should just pull anything and everything.

Honestly, at that point, I don't really feel comfortable being involved at all, and the only thing we both seemed to really fundamentally agree on in that discussion was "we're done".

Bcachefs developer Kent Overstreet has his own view of the situation. Both Torvalds and Overstreet refer to a seemingly private conversation where the pull request (and other topics) were discussed.

Over on the Collabora blog, Tathagata Roy has an update on the progress of targeting the Coccinelle tool for matching and transforming source code to Rust. The Coccinelle for Rust project, which we covered in a 2024 talk by Roy at Kangrejos, is adding the ability to transform Rust programs and the goal is "to bring Coccinelle For Rust at par with Coccinelle For C in terms of basic functionalities". There is still work to be done to get there, but progress is being made in various areas.

Computational Tree Logic (CTL) is the heart of Coccinelle, which takes semantic patches and generalizes them over Rust files. Prior to using this engine, CfR used an ad-hoc method for matching patterns of code. This engine is the same as the one used for Coccinelle for C, with a few minor changes. Most of the changes were idiomatic but to the same effect. More information on the engine and its language (CTL-VW) can be found in the POPL Paper. With a standard engine, each step of the matching process can be logged, allowing us to learn and reuse the same design patterns from Coccinelle for C, including critical test cases.

Security updates have been issued by Debian (firefox-esr and libxml2), Fedora (firefox, libtpms, and tigervnc), Mageia (chromium-browser-stable and nss & firefox), Oracle (emacs, iputils, kernel, krb5, libarchive, mod_proxy_cluster, pam, perl-File-Find-Rule, perl-YAML-LibYAML, and qt5-qtbase), Red Hat (opentelemetry-collector, osbuild-composer, and weldr-client), SUSE (clamav, firefox, go1.24-openssl, and helm), and Ubuntu (libarchive, linux-azure, linux-azure-5.4, linux-azure-fips, linux-fips, linux-azure-nvidia, linux-oracle, linux-oracle-6.8, linux-raspi, linux-raspi-realtime, linux-xilinx-zynqmp, and python-urllib3).

One of the biggest changes to come to the Python world is the addition of the free-threading interpreter, which eliminates the global interpreter lock (GIL) that kept the interpreter thread-safe, but also serialized multi-threaded Python code. Over the years, the GIL has been a source of complaints about the scalability of Python code using threads, so many developers have been looking forward to the change, which has been an experimental feature since Python 3.13 was released in October 2024. Making the free-threaded version work with the rest of the Python ecosystem, especially native extensions, is an ongoing effort, however; Nathan Goldbaum and Lysandros Nikolaou spoke at PyCon US 2025 about those efforts.

The Collabora blog has a summary, written by Nicolas Dufresne, about the Linux Media Summit held on May 13 in Nice, France. It was co-located with the Embedded Recipes conference and had sessions on stateless video encoders, camera support, staging drivers, memory accounting, and a multi-committer model for the media subsystem. "Our largest Media Summit to date brought together around 20 engaged participants. Engagement was strong, marked by thoughtful questions and lively discussions."

Security updates have been issued by AlmaLinux (libblockdev and open-vm-tools), Debian (debian-security-support, gdk-pixbuf, konsole, and node-send), Fedora (apache-commons-beanutils, chromium, clamav, dotnet9.0, libblockdev, mediawiki, mingw-python-setuptools, pam, perl-File-Find-Rule, python-pycares, python-setuptools, spdlog, udisks2, and xorg-x11-server-Xwayland), Mageia (chromium-browser-stable), Oracle (apache-commons-beanutils, container-tools:ol8, gimp:2.8, idm:DL1, perl-FCGI:0.78, and postgresql), Red Hat (container-tools:rhel8, delve, git-lfs, go-toolset:rhel8, grafana, kernel, mod_auth_openidc, and spice-client-win), SUSE (apache-commons-beanutils, apache2-mod_security2, distribution, gstreamer-plugins-good, icu, ignition, perl, python310, python311, python312, and python39), and Ubuntu (apache-log4j1.2 and botan).

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.

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).

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.

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).

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).

Linus Torvalds has released 6.16-rc2, which is "admittedly even smaller than usual", though rc2 is not uncommonly one of the smaller release candidates.

It may be that people are taking a breather after a fairly sizable merge window, but it might also be seasonal, with Europe starting to see summer vacations... We'll see how this goes.

The diffstat looks somewhat unusual, with a lot of one-liners with both ARC and pincontrol having (presumably independently) ended up doing some unrelated trivial cleanups.

But even that is probably noticeable only because everything else is pretty small. That "everything else" is mostly network drivers (and bluetooth) and bcachefs, with some rust infrastructure and core networking changes thrown in.

Writeback for filesystems is the process of flushing the "dirty" (written) data in the page cache to storage. At the 2025 Linux Storage, Filesystem, Memory Management, and BPF Summit (LSFMM+BPF), Anuj Gupta led a combined storage and filesystem session on some work that has been done to parallelize the writeback process. Some of the performance problems that have been seen with the existing single-threaded writeback came up in a session at last year's summit, where the idea of doing writeback in parallel was discussed.

Security updates have been issued by AlmaLinux (kernel), Debian (chromium, gst-plugins-bad1.0, node-tar-fs, and ublock-origin), Gentoo (Emacs, File-Find-Rule, GStreamer, GStreamer Plugins, GTK+ 3, LibreOffice, Node.js, OpenImageIO, Python, PyPy, Qt, X.Org X server, XWayland, and YAML-LibYAML), Mageia (mariadb and roundcubemail), Red Hat (go-toolset:rhel8, golang, grafana, grafana-pcp, gstreamer1-plugins-bad-free, libxml2, libxslt, mod_security, nodejs:20, and perl-FCGI:0.78), Slackware (mozilla), SUSE (docker, docker-compose, iputils, kernel, libsoup, open-vm-tools, rabbitmq-server, rabbitmq-server313, wget, and yelp), and Ubuntu (libsoup2.4 and webkit2gtk).

The iov_iter interface is used to describe and iterate through buffers in the kernel. David Howells led a combined storage and filesystem session at the 2025 Linux Storage, Filesystem, Memory Management, and BPF Summit (LSFMM+BPF) to discuss ways to improve iov_iter. His topic proposal listed a few different ideas including replacing some iov_iter types and possibly allowing mixed types in chains of iov_iter entries; he would like to make the interface itself and the uses of iov_iter in the kernel better.

Security updates have been issued by AlmaLinux (golang, nodejs22, thunderbird, and varnish), Debian (gimp, modsecurity-apache, python-tornado, and roundcube), Fedora (chromium, coreutils, fcgi, ghostscript, krb5, libvpx, mingw-gstreamer1-plugins-bad-free, mingw-libsoup, mod_security, and samba), Mageia (php-adodb, systemd, and tomcat), Red Hat (buildah, firefox, glibc, grafana, kernel, libsoup, libxslt, mod_security, perl-FCGI, podman, python-tornado, and skopeo), Slackware (libvpx), and SUSE (helm-mirror, iputils, and libraw).

In a combined storage and filesystem session at the 2025 Linux Storage, Filesystem, Memory Management, and BPF Summit (LSFMM+BPF), Keith Busch led a discussion about zero-copy operations for the Filesystem in Userspace (FUSE) subsystem. The session was proposed by his colleague, David Wei, who could not make it to the summit, so Busch filled in, though he noted that "I do not really know FUSE so well". The idea is to eliminate data copies in the data path to and from the FUSE server in user space.