The LWN.net Weekly Edition for February 21, 2019 is available.

On his blog, Karim Yaghmour writes about an experimental social network that he and a colleague cobbled together using Git. While it is simply a proof of concept at this point, he is looking for feedback and, perhaps, collaborators to take it further. "It turns out that git has practically everything that's needed to act both as storage and protocol for a social network. Not only that, but it's very well-known within and used, deployed and maintained in the circles I navigate, it scales very well (see github), it's used for critical infrastructure (see kernel.org), it provides history, it's distributed by nature, etc. It's got *almost* everything, but not quite everything needed. So what's missing from git? A few basic things that it turns out aren't very hard to take care of: ability to 'follow', getting followee notifications, 'commenting' and an interface for viewing feeds. And instead of writing a whole online treatise of how this could be done, I asked my colleague Francois-Denis Gonthier to implement a proof and concept of this that we called 'gitgeist' and just published on github [https://github.com/opersys/gitgeist-poc]."

These days applications are generally moving away from the desktop and toward the mobile space. But taking a multi-platform desktop application and adding two mobile platforms into the mix is difficult to do, as Dirk Hohndel described in his linux.conf.au 2019 talk. Hohndel maintains the Subsurface dive log application, which has added mobile support over the past few years; he wanted to explain the process that the project went through to support all of those platforms. As the subtitle of the talk, "Developing for multiple platforms without losing your mind", indicates, it is a hard problem to solve sanely.

Stable kernels 4.20.11, 4.19.24, 4.14.102, 4.9.159, 4.4.175, and 3.18.135 have been released. They all contain important fixes and users should upgrade.

Security updates have been issued by Debian (ansible, drupal7, and systemd), Fedora (botan2, ceph, and firefox), Oracle (firefox, flatpak, and systemd), Red Hat (firefox), SUSE (gvfs, kernel, libqt5-qtbase, python-numpy, and qemu), and Ubuntu (gdm3).

The digiKam team has announced the release of digiKam 6.0.0. New features include full support of video files management working as photos; an integration of all import/export web-service tools in LightTable, Image editor, and Showfoto; raw file decoding engine supporting new cameras; similarity data is now stored in a separate file; simplified web-service authentication using OAuth protocol; and more.

When patents and free software crop up together, the usual question is about patent licensing. Patent exhaustion — the principle that patent rights don't reach past the first sale of a product — is much less frequently discussed. At FOSDEM 2019, US lawyer Van Lindberg argued that several US court decisions related to exhaustion, most of them recent but some less so, could come together to have surprising beneficial effects for free software. He was clear that the argument applied only in the US but, since court systems tend to look to each other for consistency's sake, and because Lindberg is an engaging speaker, the talk was of great interest even in Brussels.

Security updates have been issued by Debian (chromium, rdesktop, rssh, systemd, and uriparser), Fedora (bouncycastle, eclipse-jgit, eclipse-linuxtools, jackson-annotations, jackson-bom, jackson-core, jackson-databind, jackson-dataformat-xml, jackson-dataformats-binary, jackson-dataformats-text, jackson-datatype-jdk8, jackson-datatype-joda, jackson-datatypes-collections, jackson-jaxrs-providers, jackson-module-jsonSchema, jackson-modules-base, jackson-parent, moby-engine, and subversion), openSUSE (chromium, docker-runc, firefox, GraphicsMagick, kernel, LibVNCServer, php7, pspp, spread-sheet-widget, and runc), SUSE (kernel-firmware, qemu, and systemd), and Ubuntu (nss and systemd).

The Debian project has announced the eighth update of Debian 9 "stretch". As a stable point release, this version mainly adds bugfixes for security issues and other serious problems. Click below for a list of changes.

Regressions are an unavoidable side effect of software development; the kernel is no different in that regard. The 5.0 kernel introduced a change in the handling of the "#!" (or "shebang") lines used to indicate which interpreter should handle an executable text file. The problem has been duly fixed, but the incident shows how easy it can be to introduce unexpected problems and highlights some areas where the kernel's development process does not work as well as we might like.

Security updates have been issued by Arch Linux (cairo, firefox, flatpak, hiawatha, and webkit2gtk), Debian (gsoap, mosquitto, php5, thunderbird, and tiff), Fedora (elfutils, ghostscript, gsi-openssh, kernel, kernel-headers, kernel-tools, kf5-kauth, mingw-podofo, mingw-poppler, mosquitto, podofo, and python-markdown2), Mageia (firefox, flash-player-plugin, lxc, and thunderbird), openSUSE (avahi, docker, libu2f-host, LibVNCServer, nginx, phpMyAdmin, and pspp, spread-sheet-widget), Red Hat (rhvm-appliance), and SUSE (python-numpy).

The 5.0-rc7 kernel prepatch has been released. Linus says: "Nothing particularly odd stands out, and everything is pretty small. Just the way I like it."

Version 0.13.0 of the Geary graphical email client is out. "This is a major new release, featuring a number of new features — including a new user interface for creating and managing email accounts, integration with GNOME Online Accounts (which also provides OAuth login support for some services), improvements in displaying conversations, composing new messages, interacting with other email apps, reporting problems as they occur, and number of important bug fixes, server compatibility fixes, and security fixes."

The Ubuntu team has announced the release of Ubuntu 18.04.2 LTS for its Desktop, Server, and Cloud products, as well as other flavors of Ubuntu with long-term support. Support periods vary for different flavors. "Like previous LTS series, 18.04.2 includes hardware enablement stacks for use on newer hardware. This support is offered on all architectures and is installed by default when using one of the desktop images." Ubuntu Server installs the GA kernel, however the HWE kernel may be selected from the installer bootloader.

Software interrupts (or "softirqs") are one of the oldest deferred-execution mechanisms in the kernel, and that age shows at times. Some developers have occasionally been heard to mutter about removing them, but softirqs are too deeply embedded into how the kernel works to be easily ripped out; most developers just leave them alone. So the recent per-vector softirq masking patch set from Frederic Weisbecker is noteworthy as an exception to that rule. Weisbecker is not getting rid of softirqs, but he is trying to reduce their impact and improve their latency.

Greg Kroah-Hartman released a set of stable kernels that should *not* be used, including: 4.20.9, 4.19.22, 4.14.100, and 4.9.157. Those kernels caused a regression that was reverted in the following kernels: 4.20.10, 4.19.23, 4.14.101, and 4.9.158.

Security updates have been issued by Debian (firefox-esr and unbound), Fedora (docker, libexif, and runc), openSUSE (mozilla-nss, python, rmt-server, and thunderbird), Slackware (mozilla), and SUSE (couchdb, dovecot23, kvm, nodejs6, php53, podofo, python-PyKMIP, rubygem-loofah, util-linux, and velum).

The cynical among us might be tempted to think that an announcement from the GNOME project about the removal of a feature — a relatively unused feature at that — would be an unremarkable event. In practice, though, Debarshi Ray's announcement that the GNOME Online Accounts (GOA) subsystem would no longer support the "documents" access point touched off a lengthy discussion within the project itself. The resulting discussion revealed a few significant problems with GOA and, indeed, with the concept of online-account management in any sort of open-source umbrella project like GNOME.

Security updates have been issued by Debian (python-gnupg), Mageia (avahi, dom4j, gvfs, kauth, libwmf, logback, mad, python, python-django, and radvd), openSUSE (curl, haproxy, lua53, python-slixmpp, runc, spice, and uriparser), Red Hat (flash-plugin), Slackware (mozilla), and SUSE (build and docker-runc).

The PostgreSQL project has put out updated releases for all supported versions. "This release changes the behavior in how PostgreSQL interfaces with 'fsync()' and includes fixes for partitioning and over 70 other bugs that were reported over the past three months." The fsync() issue was covered here in April 2018.