All posts by jake

[$] Tracepoints for the VFS?

Post Syndicated from jake original https://lwn.net/Articles/1017573/

Adding tracepoints to some kernel subsystems has been controversial—or
disallowed—due to concerns about the user-space
ABI
that they might create. The virtual filesystem (VFS) layer has
long been one of the subsystems that has not allowed any tracepoints, but
that may be changing. At the 2025 Linux Storage, Filesystem, Memory
Management, and BPF Summit (LSFMM+BPF), Ted Ts’o led a discussion about
whether the ABI concerns are outweighed by the utility of tracepoints for
the VFS.

Security updates for Thursday

Post Syndicated from jake original https://lwn.net/Articles/1017919/

Security updates have been issued by Debian (chromium and libapache2-mod-auth-openidc), Oracle (expat, freetype, glibc, grub2, gvisor-tap-vsock, and kernel), Red Hat (grub2 and webkit2gtk3), and SUSE (apache2-mod_auth_openidc, cosign, gitoxide, govulncheck-vulndb, GraphicsMagick, haproxy, hauler, mozjs52, oci-cli, pam, perl-Data-Entropy, poppler, python-lxml-doc, python311-aiohttp, rekor, rubygem-rexml, and webkit2gtk3).

[$] Parallel directory operations

Post Syndicated from jake original https://lwn.net/Articles/1017477/

Allowing directories to be modified in parallel was the topic of Jeff
Layton’s filesystem-track session at the 2025 Linux Storage, Filesystem,
Memory Management, and BPF Summit (LSFMM+BPF). There are certain use
cases, including for the NFS and Lustre filesystems, as mentioned in a patch set
referenced in the topic
proposal
, where contention in creating multiple files in a directory is
causing noticeable performance problems. In some testing, Layton has found
that the inode read-write semaphore (i_rwsem) for the directory is
serializing operations; he wanted to discuss alternatives.

[$] Topics from the virtual filesystem layer

Post Syndicated from jake original https://lwn.net/Articles/1017128/

In the first filesystem-track session at the 2025 Linux Storage,
Filesystem, Memory Management, and BPF Summit (LSFMM+BPF), virtual
filesystem (VFS) layer co-maintainer Christian Brauner had a few different
topics he wanted to talk about. Issues on the agenda
included iterating through anonymous mount namespaces, a needed feature
for ID-mapped mounts, the perennial unprivileged mounts topic, potentially
using hazard pointers for file reference counting, and Rust bindings. He
did not expect to get through all of them in the 30 minutes allotted, but
the session did move along pretty quickly to at least
introduce them to the assembled filesystem developers.

Security updates for Monday

Post Syndicated from jake original https://lwn.net/Articles/1017396/

Security updates have been issued by Debian (glib2.0, jinja2, kernel, mediawiki, perl, subversion, twitter-bootstrap3, twitter-bootstrap4, and wpa), Fedora (c-ares, chromium, condor, corosync, cri-tools1.29, exim, firefox, matrix-synapse, nextcloud, openvpn, perl-Data-Entropy, suricata, upx, varnish, webkitgtk, yarnpkg, and zabbix), Mageia (giflib, gnupg2, graphicsmagick, and poppler), Oracle (delve and golang, go-toolset:ol8, grub2, and webkit2gtk3), Red Hat (kernel and kernel-rt), SUSE (chromium, fontforge-20230101, govulncheck-vulndb, kernel, liblzma5-32bit, pgadmin4, python311-Django, and python311-PyJWT), and Ubuntu (graphicsmagick).

[$] Atomic writes for ext4

Post Syndicated from jake original https://lwn.net/Articles/1016879/

Building on the discussion in the two previous sessions on untorn (or
atomic) writes, for buffered I/O and for XFS using direct I/O, Ojaswin Mujoo
remotely led a
session on support for the feature on ext4. That took place in the combined storage and
filesystem track at the
2025 Linux Storage, Filesystem, Memory Management, and BPF Summit. Part of
the support for the feature is already in the upstream kernel, with more
coming. But
there are still some challenges that Mujoo wanted to discuss.

Malcolm: 6 usability improvements in GCC 15

Post Syndicated from jake original https://lwn.net/Articles/1017132/

Over on the Red Hat Developer site, David Malcolm has an article
about improvements in GCC 15
, specifically focusing on the diagnostic
information that the compiler emits. This includes ASCII art with a “⚠️”
warning emoji to display the execution path when it detects a problem (like
an infinite loop in one of his examples), better C++ template errors,
machine-readable diagnostics using Static
Analysis Results Interchange Format
(SARIF), better messages regarding
C23 compatibility since that is the default C version for GCC 15, and more.
Since the changes are focused on messages, there is the inevitable color
scheme update as well:

GCC will use color when emitting its text messages on stderr at a suitably modern terminal, using a few colors that seem to work well in a number of different terminal themes—but the exact rules for choosing which color to use for each aspect of the output have been rather arbitrary.

For GCC 15, I’ve gone through C and C++’s errors, looking for places where two different things in the source are being contrasted, such as type mismatches. These diagnostics now use color to visually highlight and distinguish the differences.

Security updates for Thursday

Post Syndicated from jake original https://lwn.net/Articles/1017043/

Security updates have been issued by AlmaLinux (tomcat and webkit2gtk3), Debian (chromium), Fedora (ghostscript), Mageia (atop, docker-containerd, and xz), Red Hat (go-toolset:rhel8), SUSE (apache2-mod_auth_openidc, apparmor, etcd, expat, firefox, kernel, libmozjs-128-0, and libpoppler-cpp2), and Ubuntu (dino-im, linux, linux-aws, linux-aws-hwe, linux-azure, linux-azure-4.15, linux-gcp,
linux-gcp-4.15, linux-hwe, linux-kvm, linux-oracle, linux, linux-aws, linux-kvm, linux-lts-xenial, linux-fips, linux-fips, linux-aws-fips, linux-azure-fips, linux-gcp-fips, opensc, and poppler).

[$] An update on torn-write protection

Post Syndicated from jake original https://lwn.net/Articles/1016406/

In a combined storage and filesystem track session at the
2025 Linux Storage, Filesystem, Memory Management, and BPF Summit, John
Garry continued the theme of “untorn” (or atomic) writes that started in the previous session. It was also
an update on where things have gone for untorn writes since his session at last year’s summit. Beyond that,
he looked at some of the plans and challenges for the feature in the future.

Security updates for Monday

Post Syndicated from jake original https://lwn.net/Articles/1016663/

Security updates have been issued by Debian (abseil, atop, jetty9, ruby-saml, tomcat10, trafficserver, xz-utils, and zfs-linux), Fedora (chromium, condor, containernetworking-plugins, cri-tools1.29, crosswords-puzzle-sets-xword-dl, exim, ghostscript, matrix-synapse, upx, varnish, and yarnpkg), Gentoo (XZ Utils), Mageia (augeas, corosync, nss & firefox, and thunderbird), Oracle (container-tools:ol8, firefox, freetype, and kernel), Red Hat (firefox), SUSE (chromium, gn, firefox-esr, go1.23-1.23.8, go1.24, go1.24-1.24.2, google-guest-agent, govulncheck-vulndb, gsl, python311-ecdsa, thunderbird, and webkit2gtk3), and Ubuntu (kamailio, libdbd-mysql-perl, linux-nvidia, linux-nvidia-6.8, and tomcat9).

[$] Supporting untorn buffered writes

Post Syndicated from jake original https://lwn.net/Articles/1016015/

At last year’s
Linux Storage, Filesystem,
Memory-Management, and BPF Summit (LSFMM+BPF), there was a discussion about atomic writes that was
accompanied by patches to support the feature in the block layer, and for
direct I/O on XFS. That
work was merged, but another piece of that discussion concerned adding the
feature for buffered I/O, in part because the PostgreSQL database currently
has to jump through hoops to ensure that its writes are not “torn”
(partially written) when there is an error or crash. Luis Chamberlain led
a combined storage and filesystem track at this year’s summit to revisit
the idea of providing atomic (or untorn) writes for buffered I/O.

Security updates for Thursday

Post Syndicated from jake original https://lwn.net/Articles/1016361/

Security updates have been issued by AlmaLinux (expat), Debian (chromium, commons-vfs, firefox-esr, php-horde-editor, php-horde-imp, and thunderbird), Fedora (corosync, firefox, nextcloud, and suricata), Mageia (curl and upx), Oracle (emacs, fence-agents, freetype, kernel, libreoffice, libxml2, nginx:1.24, podman, python-jinja2, and tigervnc), Red Hat (firefox and python-jinja2), SUSE (assimp, ffmpeg-4, firefox, ghostscript, GraphicsMagick, libxslt, and tomcat), and Ubuntu (linux, linux-aws, linux-aws-5.15, linux-gcp, linux-gke, linux-gkeop,
linux-ibm, linux-intel-iotg, linux-kvm, linux-lowlatency,
linux-lowlatency-hwe-5.15, linux-meta-raspi, linux-nvidia-tegra,
linux-oracle, linux-oracle-5.15, linux-raspi, linux, linux-azure, linux-azure-5.4, linux-bluefield, linux-gcp,
linux-ibm, linux-kvm, linux-oracle, linux-oracle-5.4, linux-xilinx-zynqmp, linux-fips, linux-fips, linux-aws-fips, linux-gcp-fips, linux-hwe-5.15, and linux-realtime, linux-intel-iot-realtime).

[$] LWN.net Weekly Edition for April 3, 2025

Post Syndicated from jake original https://lwn.net/Articles/1015512/

Inside this week’s LWN.net Weekly Edition:

  • Front: Calibre 8.0; Fedora reproducibility; OpenWrt One; 6.15 Merge Window; LSFMM+BPF coverage including BPF in GCC, Rust merging process, and more.
  • Briefs: Ubuntu namespaces; New FPL; PorteuX 2.0; Firefox 137.0; GCC Rust; Rockbox 4.0; Rust specification; Thundermail; Dave Täht RIP; Quotes; …
  • Announcements: Newsletters, conferences, security updates, patches, and more.

[$] Updates on storage standards

Post Syndicated from jake original https://lwn.net/Articles/1015724/

As he has in some previous editions of the Linux Storage, Filesystem,
Memory-Management, and BPF Summit (LSFMM+BPF), Fred Knight gave an update
on the status of various storage standards this year. In it, he looked at
changes to the NVM Express (NVMe)
standards in some detail. He also updated attendees on the fairly small
changes that have come to the SCSI (T10)
and ATA (T13) standards over the last few
years.

Security updates for Monday

Post Syndicated from jake original https://lwn.net/Articles/1015968/

Security updates have been issued by Debian (amd64-microcode, flatpak, intel-microcode, libdata-entropy-perl, librabbitmq, and vim), Fedora (augeas, containerd, crosswords-puzzle-sets-xword-dl, libssh2, libxml2, nodejs-nodemon, and webkitgtk), Red Hat (libreoffice and python-jinja2), SUSE (389-ds, apparmor, corosync, docker, docker-stable, erlang26, exim, ffmpeg-4, govulncheck-vulndb, istioctl, matrix-synapse, mercurial, openvpn, python3, rke2, and skopeo), and Ubuntu (ansible, linux, linux-hwe-5.4, linux-azure, linux-azure-5.4, linux-bluefield, linux-gcp, linux-gcp-5.4,
linux-ibm, linux-kvm, linux-oracle, linux-oracle-5.4, linux-xilinx-zynqmp, linux-azure-fips, linux-gcp-fips, linux-fips, linux-fips, linux-aws-fips, linux-azure-fips, linux-gcp-fips, linux-nvidia-tegra, linux-nvidia-tegra-igx, linux-realtime, linux-intel-iot-realtime, linux-xilinx-zynqmp, opensc, and ruby-doorkeeper).

[$] Making the OpenWrt One

Post Syndicated from jake original https://lwn.net/Articles/1014998/

In a keynote on the final day of SCALE 22x, Denver
Gingerich said that he wanted to talk “a little bit about a router and
also the big picture around that router
“. Gingerich is the director of
compliance at the Software Freedom
Conservancy
(SFC), which is the organization behind the OpenWrt One router that
LWN looked at back in November. The
router is, of course, based on firmware from the
OpenWrt project, which got its
start because of GPL-enforcement activities and is a member project at the SFC.

[$] Lessons from open source in the Mexican government

Post Syndicated from jake original https://lwn.net/Articles/1013776/

The adoption of open-source software in governments has had its ups and
downs. While open source seems like a “no-brainer”, it turns out that
governments can be surprisingly resistant to using FOSS for a variety of
reasons. Federico González Waite spoke in the Open Government track at SCALE 22x in Pasadena,
California to recount his experiences
working with and for the Mexican government
. He led multiple projects
to switch away from proprietary, often predatory, software companies with
some success—and failure.

Security updates for Monday

Post Syndicated from jake original https://lwn.net/Articles/1015286/

Security updates have been issued by Debian (libxslt, mercurial, and webkit2gtk), Fedora (chromium, dotnet8.0, ffmpeg, jupyterlab, and kitty), Mageia (expat and libxslt), Red Hat (pcs), SUSE (apptainer, chromium, kernel, libarchive, mercurial, python311, radare2, xorg-x11-server, and zvbi), and Ubuntu (golang-github-cli-go-gh-v2 and nltk).