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[$] Limiting negative dentries
A number of problems related to negative directory entries (dentries) were the topic of a filesystem-track session at the 2026 Linux Storage, Filesystem, Memory Management, and BPF Summit. Negative dentries are used to indicate that a file of a given name does not exist in a directory; it is an optimization that short-circuits the lookup of the file name when the answer is already known. Miklos Szeredi led a session that discussed some problems that come from having too many negative dentries for a directory.
[$] Two LLM-assisted memory-management patch sets
The kernel community (like many other free-software projects) has recently seen a large influx of patches developed with the assistance of large language models (LLMs). Those patches tend to come from developers who were previously unknown to the community. At the moment, though, the memory-management developers are evaluating two large patch sets, developed with LLM assistance, that were submitted by established and well-respected developers. The rather different reception accorded to that work may give insights into how LLM-generated contributions will be handled going forward.
[$] LWN.net Weekly Edition for July 2, 2026
Posted Jul 2, 2026 0:18 UTC (Thu)The LWN.net Weekly Edition for July 2, 2026 is available.
Inside this week's LWN.net Weekly Edition
- Front: Xsnow protestware; Git 2.55; Rhombus; kernel hardening; More LSFMM+BPF coverage; 7.2 merge window; Secure Boot certificate expiration; Ceph and Garage; OSPM 2026.
- Briefs: Akrites; Mageia 10; Git 2.55.0; Podman 6.0; systemd v261; Creative Commons chat; Quotes; ...
- Announcements: Newsletters, conferences, security updates, patches, and more.
[$] Efficient access to local storage for BPF programs
When a BPF program is used to filter or redirect packets in the networking subsystem, the program will often want to associate data with each packet as it moves through the kernel. The kernel's local BPF storage API, which associates extra data with some kernel objects, provides a way to do that. (See also the BPF map types that end in STORAGE.) Amery Hung and Jakub Sitnicki led two sessions at the 2026 Linux Storage, Filesystem, Memory-Management, and BPF Summit about how to make accesses to local storage data more efficient. Hung spoke about general performance problems related to locking, while Sitnicki examined the use of local storage in the networking subsystem in particular.
[$] Secure Boot certificate expiration is here
Linux users who have Secure Boot enabled on their systems rely on certificates issued by Microsoft to verify the software used to boot a system is trusted by the user. One of those certificates expired recently, but that will not cause systems that are able to boot to stop doing so. There are situations where the expiration may cause problems, however, and the window for relying on existing signed binaries is shorter than it might appear. Users and administrators will want to stay on top of these changes. Over the last year, part of my job at Microsoft has been to work on this problem. LWN wrote about the certificate expiration in July 2025, and this article follows up with where we are now.
[$] Flexible metaprogramming with Rhombus
Lisp-like languages have historically led the world in metaprogramming and flexibility. While many modern languages have adopted the idea of macros, Lisp-like languages such as Racket have continued pushing the envelope, attempting to make macros as easy as possible to incorporate into everyday programs. On the other hand, Lisp's minimal, parenthesis-based syntax can be hard to adapt to — to the point that Lisp is sometimes said to stand for "Lots of Irritating Silly Parentheses". Rhombus is a new programming language that aims to have the best of both worlds, marrying Racket's metaprogramming capabilities to a simple Python-like syntax and reasonable standard-library defaults.
[$] The rest of the 7.2 merge window
Linus Torvalds released 7.2-rc1 and closed the 7.2 merge window on June 28; by that time, 13,412 non-merge commits had found their way into the mainline. That makes this the busiest merge window since the 6.7 development cycle in 2024 (15,418 commits, including 2,800 for the entire bcachefs development history). Just under half of those commits arrived after LWN's summary of the first half of the merge window was written. As usual, the commits in the latter part of the merge window were more heavily focused on fixes, but there were still a lot of new features and significant changes merged as well.
[$] Xsnow "protestware" in Debian
The xsnow application, which generates an animated snowfall effect (and other pleasant diversions) for X11 desktops, does not seem like an obvious channel for political statements. Nevertheless, xsnow's maintainer seems to have included a political protest in the program: an Easter egg that is triggered when the program's language is set to Russia ("ru"). One user has complained that this functionality should be removed from the Debian xsnow package, but Debian does not seem to have any rules that forbid such a feature outright.
[$] Reports from OSPM 2026, day three
The Power Management and Scheduling in the Linux Kernel Summit, which still goes by the historical acronym OSPM, was held in Cambridge, UK, in mid-April. As has become traditional, the presenters at that event have since written summaries of their sessions, and this work has kindly been made available to LWN for publication. The third day's sessions covered a wide range of topics, including GPU affinity, profile-guided scheduling, paravirtualization scheduling, quality of service, and more.
[$] Initiating writeback earlier
Writeback is the process of ensuring that dirty pages or folios in the page cache are flushed to the disk, so that changes to those files are made persistent. In a filesystem-track session at the 2026 Linux Storage, Filesystem, Memory Management, and BPF Summit, Jeff Layton wanted to discuss whether the writeback operation should be initiated earlier than it is today. The consensus seemed to be that it should be done earlier, but the path toward making that happen was less clear.
Seven stable kernels for Saturday including two security fixes
Greg Kroah-Hartman has announced the release of the 7.1.3, 6.18.38, 6.12.95, 6.6.144, 6.1.177, 5.15.211, and 5.10.260 stable kernels. Several kernels in this batch include a fix for a vulnerability introduced in the 6.0 kernel in IPv6 (CVE-2026-53362), which could allow an attacker to escape a container and gain root access.
There is also a fix for a use-after-free bug in KVM (CVE-2026-53359) that was introduced in the 2.6.36 kernel. As usual, each stable kernel includes a number of fixes throughout the tree. Users are advised to upgrade.
Four vulnerabilities in Guix
The GNU Guix project has announced three vulnerabilities in the guix substitute utility as well as a fourth that affects the guix pull and guix time-machine commands. The impact of the vulnerabilities ranges from remote privilege escalation to local disclosure of sensitive files.
The remote exploitation of guix substitute only requires that the vulnerable system attempt to download a binary substitute. Any configured substitute server, including ones discovered using guix-daemon's --discover option, can exploit this, and so can a man-in-the-middle (MITM), regardless of whether https is used in the substitute server urls.
The local exploitation of guix substitute only requires the ability to connect to guix-daemon's socket, which by default any user can do.
Separately, another security issue (CVE ID pending) was identified in guix pull and guix time-machine, which enables anyone who can control the channels file used by these commands to cause a file to be created or overwritten wherever the user running the command in question has permission to create them.
The project is recommending that all users upgrade guix and guix-daemon immediately. See the announcement for instructions, how to test for the vulnerabilities, the disclosure timeline, and more.
Security updates for Friday
Security updates have been issued by AlmaLinux (389-ds-base, bind9.18, evince, fence-agents, freerdp, frr, frr10, gimp, gnutls, hplip, jmc, mariadb:11.8, mysql:8.4, php:7.4, postgresql-jdbc, postgresql:15, postgresql:16, valkey, xorg-x11-server, and xorg-x11-server-Xwayland), Debian (fastnetmon), Fedora (7zip, apptainer, cpp-httplib, mysql8.4, and nmap), Oracle (freerdp, giflib, glib2, glibc, kernel, libreoffice, libvirt, mariadb:10.11, postgresql, python3.11, python3.12, rrdtool, and thunderbird), Red Hat (buildah, podman, and skopeo), SUSE (alloy, apache2, buildah, c3p0, containerd, crun, cups, dhcpcd, dnsmasq, docker-stable, dracut, editorconfig-core-c, ffmpeg-7, fontforge, google-guest-agent, google-osconfig-agent, graphicsmagick, gstreamer-plugins-bad, gstreamer-plugins-good, helm, jackson-annotations, jackson-core, jackson-databind, jline3, kernel, kubectl-cnpg, lcms2, libslirp, libssh2_org, libxreaderdocument3, openbabel, openssl-3, pacemaker, perl-CGI-Session, perl-list-someutils-xs, python-lxml, python-tornado, python-tornado6, python3-onionshare, python311-python-engineio, sg3_utils, thunderbird, transmission, and trivy), and Ubuntu (cifs-utils, kernel, libvncserver, linux-aws-6.8, linux-gcp-6.8, linux-gke, linux-gkeop, linux-ibm-6.8, linux-nvidia-lowlatency, linux-oracle-6.8, linux-lowlatency, linux-lowlatency-hwe-6.8, linux-nvidia-tegra, linux-oracle-5.15, linux-raspi, linux-xilinx, nghttp2, nginx, perl, and vim).
CalyxOS is back
In August 2025, the CalyxOS privacy-focused
Android distribution announced
that it was pausing all releases while it reworked its
release process, security protocols, and changed its signing keys
following the departure of one of its founders. The project has now announced
that it is "officially back from the hiatus
" with the
7.2.2.0 release.
CalyxOS 7.2.2.0 is signed by us using a new HSM-based, open-source signing solution we designed to enhance the security of the entire signing process, ensure redundancy, and remove single points of failure. You can verify CalyxOS 7.2.2.0 and future builds following these instructions. For anyone who is interested, the security audit report of the HSM provisioning ceremony script can be found here.
In addition, we also went through significant infrastructure improvements. In particular, we have set up a cleaner server structure to streamline each release. In response to Google's less frequent AOSP source code releases, our team developed scripts to reduce the overhead in applying monthly patches and updates. Please keep in mind, additional manual steps are still needed to compensate for AOSP changes, such as requesting and storing kernel sources with each update. Currently, our lead engineer is continuing the maintenance of the base device trees for both LineageOS and CalyxOS to bridge the gap created by the absence of Google Pixel device trees.
Kernel archive /pub tree restoring
A few astute observers have noticed that some content on kernel.org had disappeared and were understandably concerned. Konstantin Ryabitsev has provided an update via social.kernel.org:
There was an unfortunate error while changing the kernel.org primary/secondary mirroring infrastructure, which resulted in the /pub tree suddenly becoming empty. No data was lost, just public mirror copies. Everything is now being restored, but deletes are fast and restores are slow, so thank you for your patience!
The incident is being tracked on the Linux Foundation's IT status page.
Spoofed email from LWN
We were made aware today of an email sent to a reader that was spoofed to appear to be from LWN. The message claimed, among other things, that we were providing personal information about the reader to another site user. As is explained in our privacy policy we do not, and would not, provide such information.
If any other readers have received an odd message from LWN, it is an attempt at a hoax; if in doubt, please check the DKIM header of the email. Any email that does come from LWN will have a proper DKIM signature in its headers.
If you receive such a message, please feel free to send it to us, with its headers intact. But to reiterate, we are not providing any user information upon request, nor banning any accounts. We hope this will not be a recurring problem.
Fedora Council proposes pausing Community Initiatives
Aoife Moloney has, on behalf of the Fedora Council, posted an
announcement that the Fedora Council is "proposing we pause the
Community Initiatives process as an official project process
"
because it has decided the current process is ineffective. It is also
closing discussion regarding the AI developer desktop
initiative covered by LWN in May.
The Fedora Objectives/Initiatives framework was never intended as a mandatory prerequisite to do the work in Fedora. It supposed to help by focusing the community on a certain work when needed, not to decide what is allowed. The AI developer desktop initiative proposal highlighted that the Community Initiatives process has failed to serve as a good framework in Fedora where new ideas can surface, receive respectful feedback, and gain Council support for work that fits the project's present and/or future. This is something that the Council must address.
As a first step, we would like to halt the community initiative process immediately. Existing initiatives in flight (Fedora Forge, Atomic, and Fedora Docs 2026) will continue with full Council backing. Their underlying work will be completed as planned in their current timeboxed state, though the administrative framework around them may evolve. As a second step, we would like to work out a new mechanism to allow Council to set strategic direction in an open, transparent way that more intentionally includes the community voice. We recognise that we have to be better at being more open in our discussions and decision making.
The council is considering the "sandbox" proposal as an alternative or supplement to a process that replaces the Community Initiatives.
Security updates for Thursday
Security updates have been issued by AlmaLinux (giflib, kernel, mariadb:10.11, mod_http2, php, rrdtool, ruby, ruby:3.3, and ruby:4.0), Debian (jq and node-lodash), Fedora (caddy, hut, ipp-usb, kernel, opkssh, rclone, thunderbird, and transmission), SUSE (389-ds, 7zip, alsa, amazon-ecs-init, avahi, cadvisor, cosign, cups, dnsdist, docker, dracut, firefox, firewalld, giflib, glib-networking, glycin-loaders, google-cloud-sap-agent, google-guest-agent, gsasl, hauler, helm, ImageMagick, kernel, keylime, krb5, libaom, libexif, libgcrypt, libnfs, libssh2_org, loupe, lrzip, mutt, ncurses, nodejs22, openCryptoki, openssh, openssl-3, pacemaker, perl-Config-IniFiles, perl-CSS-Minifier-XS, perl-DBI, perl-JavaScript-Minifier-XS, perl-libwww-perl, postfix, python-click, python-idna, python-Markdown, python-joblib, python-handy-archives, python-apache-libcloud, python-WebOb, python-PyGithub, python-soupsieve, python-pip, python-pytest-html, python-python-dotenv, python-python-multipart, python-starlette, python-tornado6, python-zeroconf, python311, python311-jupyter-server, rpcbind, sed, sg3_utils, tar, tiff, and util-linux), and Ubuntu (kernel, linux, linux-aws, linux-aws-5.15, linux-aws-fips, linux-azure, linux-azure-5.15, linux-azure-fde-5.15, linux-fips, linux-gcp, linux-gcp-fips, linux-gke, linux-gkeop, linux-hwe-5.15, linux-ibm, linux-ibm-5.15, linux-intel-iot-realtime, linux-intel-iotg, linux-kvm, linux-lowlatency, linux-lowlatency-hwe-5.15, linux-nvidia, linux-nvidia-tegra, linux-nvidia-tegra-5.15, linux-nvidia-tegra-igx, linux-oracle, linux-realtime, linux, linux-aws, linux-aws-fips, linux-gcp, linux-gcp-fips, linux-ibm, linux-nvidia, linux-nvidia-6.8, linux-oracle, linux-realtime, linux-realtime-6.8, linux-oem-6.17, and linux-oem-7.0).
Security updates for Wednesday
Security updates have been issued by AlmaLinux (coreutils, galera and mariadb11.8, giflib, git-lfs, glibc, httpd, kernel, mariadb10.11, mod_md, perl-Archive-Tar, perl-IO-Compress, perl:5.32, rrdtool, ruby, ruby4.0, and thunderbird), Debian (debian-security-support, librabbitmq, and nginx), Fedora (chromium, collectd, maradns, python-django-haystack, python-jupytext, varnish, varnish-modules, and vmod-querystring), Oracle (firefox, git-lfs, kernel, nginx:1.24, openssl, perl-Archive-Tar, perl-IO-Compress, and uek-kernel), Red Hat (container-tools:rhel8), SUSE (7zip, apache2, buildah, cifs-utils, curl, docker, exiv2-0_26, libonnxruntime1, libsoup, nodejs22, opensc, pacemaker, perl-Config-IniFiles, podman, sg3_utils, socat, tar, tracker, and xdg-desktop-portal), and Ubuntu (curl, hplip, libgd-perl, libssh2, libyang, ruby2.7, ruby3.0, ruby3.2, ruby3.3, and tar).
Creative Commons founders' fireside chat (Creative Commons blog)
Dee Harris has published a summary of the recent "fireside chat" featuring Creative Commons founders Hal Abelson, Lawrence (Larry) Lessig, Molly Van Houweling, and Glenn Otis Brown. The chat was to mark the 25th anniversary of Creative Commons and included a look back at its history as well as a look at the landscape today:
Twenty-five years ago, a small group of people made a bet. They believed that if you gave creators a simple set of tools and licenses in language that a lawyer, a machine, and a human could all read, millions of people might choose to share their work with the world instead of locking it down.
The video of the chat is available on YouTube.
