Linux Weekly News

Version 15.1 of the GNU Compiler Collection has been released. Changes include implementing the C23 dialect by default, a number of new C++26 features, experimental support for unsigned integers in Fortran, a new COBOL front end, and more. See the GCC 15 changes page for details.

The 6.14.4, 6.12.25, 6.6.88, and 6.1.135 stable kernel updates have been released; each contains another set of important fixes.

Security updates have been issued by AlmaLinux (thunderbird), Debian (libbpf), Fedora (golang-github-openprinting-ipp-usb, ImageMagick, mingw-libsoup, mingw-poppler, and pgbouncer), SUSE (glib2, govulncheck-vulndb, libsoup-2_4-1, libxml2-2, mozjs60, ruby2.5, and thunderbird), and Ubuntu (linux, linux-azure, linux-azure-5.4, linux-bluefield, linux-gcp, linux-hwe-5.4, linux-ibm, linux-kvm, linux-oracle, linux-oracle-5.4, linux-aws, linux-aws-5.4, linux-gcp-5.4, linux-iot, linux-aws-fips, linux-azure-fips, linux-fips, linux-gcp-fips, linux-hwe-6.8, linux-ibm-5.4, linux-oracle-5.15, openssh, and php-twig).

The Debian Project Leader election results have been announced. Andreas Tille has been re-elected and will serve another term through April 2026. LWN looked at the election and candidates in early April.

New compiler releases often bring with them new warnings; those warnings are usually welcome, since they help developers find problems before they turn into nasty bugs. Adapting to new warnings can also create disruption in the development process, though, especially when an important developer upgrades to a new compiler at an unfortunate time. This is just the scenario that played out with the 6.15-rc3 kernel release and the implementation of -Wunterminated-string-initialization in GCC 15.

Sometimes worms have a tendency to multiply once their can is opened. James Bottomley recently encountered that situation; he led a session in the filesystem track at the 2025 Linux Storage, Filesystem, Memory Management, and BPF Summit (LSFMM+BPF) to discuss filesystem behavior with respect to suspending and resuming the system. As he noted in his topic proposal, he came at the problem because he needed a way to resynchronize the contents of efivarfs after a system resume and thought there should be an API available to use. But, as the resulting thread shows, the filesystem freeze and thaw code had never been used by the system-wide suspend and resume code. Due to a scheduling mixup, though, several of us missed Bottomley's session, including Luis Chamberlain who has been working on hooking those two pieces up; what follows is largely from a second session that Chamberlain led, with some background information from the topic-proposal discussion and an email exchange with Bottomley.

Security updates have been issued by Debian (haproxy and openrazer), Fedora (c-ares and mingw-poppler), Red Hat (thunderbird), SUSE (epiphany, ffmpeg-6, gopass, and libsoup-3_0-0), and Ubuntu (erlang, haproxy, libapache2-mod-auth-openidc, libarchive, linux, linux-aws, linux-azure, linux-azure-5.15, linux-azure-fde, linux-azure-fde-5.15, linux-gcp, linux-gke, linux-gkeop, linux-hwe-5.15, linux-ibm, linux-intel-iotg, linux-kvm, linux-lowlatency, linux-lowlatency-hwe-5.15, linux-nvidia, linux-nvidia-tegra, linux-nvidia-tegra-igx, linux-oracle, linux-raspi, linux, linux-aws, linux-azure, linux-azure-6.8, linux-ibm, linux-lowlatency, linux-lowlatency-hwe-6.8, linux-nvidia, linux-nvidia-6.8, linux-nvidia-lowlatency, linux-oem-6.8, linux-oracle, linux-oracle-6.8, linux-aws-6.8, linux-aws-fips, linux-fips, linux-gcp-fips, linux-azure-fips, linux-gcp, linux-gke, linux-gkeop, linux-gcp-6.8, linux-ibm-5.15, linux-intel-iot-realtime, linux-realtime, linux-intel-iotg-5.15, linux-realtime, perl, and yelp, yelp-xsl).

Inside this week's LWN.net Weekly Edition:

• Front: Owen Le Blanc and MCC; UID/GID drift; DMA for UIO; More LSFMM+BPF 2025 coverage.
• Briefs: EU OS; RISC-V Fedora; Ubuntu 25.04; NLnet funding; Template strings; Tor Browser 14.5; Quotes; ...
• Announcements: Newsletters, conferences, security updates, patches, and more.

The Fedora Project is looking for solutions to an interesting problem with its image-based editions and spins, such as the Atomic Desktops or CoreOS, that are created with rpm-ostree or bootc. If a package that is part of a image-based version has a user or group created dynamically on installation, and it owns files installed on the system, the system may be subject to user ID (UID) and group ID (GID) "drift" on updates. This "UID/GID drift" may come about when a new image with updates is generated, and therefore files may have the wrong ownership. This can have side-effects ranging from mildly inconvenient to serious. No solutions have been adopted just yet, but there are a few ideas on how to deal with the problem.

The NLnet Foundation has announced the projects that have received funding from its October call for grant proposals from the Next Generation Internet (NGI) Zero Commons Fund.

The selected projects all contribute, one way or another, to the mission of the Commons Fund: reclaiming the public nature of the internet. For example, there are people working on interesting open hardware projects such as the tablet MNT Reform Touch and the Solar FemtoTX motherboard — a collaborative effort to create an ultra-low power motherboard that can run on solar power. LLM2FPGA aims to enable running open source LLMs locally on programmable chips ("FPGAs") using a fully open-source toolchain. bcachefs readies itself as the next generation filesystem for Linux, improving performance, scalability and reliability when compared to legacy filesystems.

In all, 42 projects have been selected for the NGI grants which are between €5,000 and €50,000. See the announcement for the full list of selected projects, and the current projects page for other recent projects funded by NLnet.

In the filesystem track at the 2025 Linux Storage, Filesystem, Memory Management, and BPF Summit (LSFMM+BPF), Amir Goldstein wanted to resume discussing a feature that he had briefly introduced at the end of a 2023 summit session: filesystem "write barriers". The idea is to have an operation that would wait for any in-flight write() system calls, but not block any new write() calls as bigger hammers, such as freezing the filesystem, would do. His prototype implementation is used by a hierarchical storage management (HSM) system to create a crash-consistent change log, but there may be other use cases to consider. He wanted to discuss implementation options and the possibility of providing an API for user-space applications.

Security updates have been issued by AlmaLinux (bluez, expat, and postgresql:12), Fedora (chromium, golang, LibRaw, moodle, openiked, ruby, and trafficserver), Red Hat (bluez, expat, gnutls, libtasn1, libxslt, mod_auth_openidc, mod_auth_openidc:2.3, ruby:3.1, thunderbird, and xmlrpc-c), and Ubuntu (linux, linux-aws, linux-gcp, linux-hwe-6.11, linux-lowlatency, linux-lowlatency-hwe-6.11, linux-oem-6.11, linux-oracle, linux-raspi, linux-realtime, linux-azure, linux-azure-6.11, linux-gcp-6.8, and matrix-synapse).

The Linux kernel can be configured so that kernel modules must be signed or otherwise authenticated to be loaded into the kernel. Some BPF developers want that to be an option for BPF programs as well — after all, if those are going to run as part of the kernel, they should be subject to the same code-signing requirements. Blaise Boscaccy and Cong Wang presented two different visions for how BPF code signing could work at the 2025 Linux Storage, Filesystem, Memory-Management, and BPF Summit.

The Userspace I/O (UIO) subsystem was first added to the kernel by Hans J. Koch for the 2.6.32 release in 2007. Its purpose is to facilitate the writing of drivers (mostly) in user space; to that end, it provides access to a number of resources that user-space code normally cannot touch. One piece that is missing, though, is DMA addresses. A proposal to fill that gap from Bastien Curutchet is running into some opposition, though.

Security updates have been issued by AlmaLinux (java-1.8.0-openjdk, kernel, libxslt, mod_auth_openidc:2.3, and webkit2gtk3), Fedora (c-ares, giflib, jupyterlab, perl, perl-Devel-Cover, perl-PAR-Packer, prometheus-podman-exporter, python-notebook, python-pydantic-core, rpki-client, ruby, rust-adblock, rust-cookie_store, rust-gitui, rust-gstreamer, rust-icu_collections, rust-icu_locid, rust-icu_locid_transform, rust-icu_locid_transform_data, rust-icu_normalizer, rust-icu_normalizer_data, rust-icu_properties, rust-icu_properties_data, rust-icu_provider, rust-icu_provider_macros, rust-idna, rust-idna_adapter, rust-litemap, rust-ron, rust-sequoia-openpgp, rust-sequoia-openpgp1, rust-tinystr, rust-url, rust-utf16_iter, rust-version-ranges, rust-write16, rust-writeable, rust-zerovec, rust-zip, thunderbird, and uv), SUSE (erlang, erlang26, and govulncheck-vulndb), and Ubuntu (mosquitto).

Anton Protopopov kicked off the BPF track on the second day of the 2025 Linux Storage, Filesystem, Memory-Management, and BPF Summit with a discussion about permitting indirect calls in BPF. He also spoke about his continuing work on static keys, a topic which is related because the implementation of indirect jumps and static keys in the verifier use some of the same mechanisms for tracking indirect control-flow. Although some design work remains to be done, it may soon be possible to make indirect calls in BPF without any extra work compared to normal C.

The Fedora Project's RISC-V special-interest group (SIG) has announced the availability of Fedora Linux 42 images for supported RISC-V boards, as well as QEMU and container images. The SIG is working toward making RISC-V a primary architecture for Fedora, and has made significant progress in the past year.

Our upstreaming work continues apace, and we want to acknowledge that none of this progress would be possible without the incredible collaboration from maintainers across the Fedora Project and beyond. Thank you to everyone who reviewed, accepted, merged, and built our patches. Your support makes this architecture possible.

We're also excited about just how many packages build cleanly without special treatment or overlay repositories that need to be cared for. RISC-V is becoming just another architecture, and that's exactly how it should be.

The Python Steering Council accepted PEP 750 ("Template Strings") on April 10. LWN covered the discussion around the proposal, including the substantial revisions to the idea that were needed for it to be accepted. Template strings (t-strings) are a new kind of string that produces structured data instead of a raw string, allowing library authors to build their own custom template-handling logic. Since the approval happened before the cutoff for new features (May 6), support for template strings will be included in Python 3.14, scheduled for October 2025.

Ask a Linux enthusiast who created the Linux kernel, and odds are they will have no trouble naming Linus Torvalds—but many would be stumped if asked what the first Linux distribution was, and who created it. Some might guess Slackware, or its predecessor, Softlanding Linux System (SLS); both were arguably more influential but arrived just a bit later. The first honest-to-goodness distribution with a proper installer was MCC Interim Linux, created by Owen Le Blanc, released publicly in early 1992. I recently reached out to Le Blanc to learn more about his work on the distribution, what he has been doing since, and his thoughts on Linux in 2025.

Security updates have been issued by Debian (erlang, fig2dev, shadow, wget, and zabbix), Fedora (chromium, jupyterlab, llama-cpp, prometheus-podman-exporter, python-notebook, python-pydantic-core, rpki-client, rust-adblock, rust-cookie_store, rust-gitui, rust-gstreamer, rust-icu_collections, rust-icu_locid, rust-icu_locid_transform, rust-icu_locid_transform_data, rust-icu_normalizer, rust-icu_normalizer_data, rust-icu_properties, rust-icu_properties_data, rust-icu_provider, rust-icu_provider_macros, rust-idna, rust-idna_adapter, rust-litemap, rust-ron, rust-sequoia-openpgp, rust-sequoia-openpgp1, rust-tinystr, rust-url, rust-utf16_iter, rust-version-ranges, rust-write16, rust-writeable, rust-zerovec, rust-zip, uv, and webkitgtk), Slackware (libxml2 and zsh), SUSE (argocd-cli, chromium, coredns, ffmpeg-6, and firefox), and Ubuntu (imagemagick).