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The cost of fsync() is well known to filesystem developers, which is why there are efforts to provide cheaper alternatives. Ric Wheeler wanted to discuss the longstanding idea of adding an asynchronous version of fsync() in a filesystem session at the 2019 Linux Storage, Filesystem, and Memory-Management Summit (LSFMM). It turns out that what he wants may already be available via the new io_uring interface.

The Mozilla blog takes a look at the Firefox 67 release. "Today’s new Firefox release continues to bring fast and private together right at the crossroads of performance and security. It includes improvements that continue to keep Firefox fast while giving you more control and assurance through new features that your personal information is safe while you’re online with us." See the release notes for more information.

The "guarantees" that existing filesystems make with regard to persistence in the face of a system crash was the subject of a session led by Amir Goldstein at the 2019 Linux Storage, Filesystem, and Memory-Management Summit (LSFMM). The problem is that filesystem developers are not willing to make much in the way of guarantees unless applications call fsync()—something that is not popular with application developers, who want a cheaper option.

The kernel mailing lists carry the sad news that longtime kernel contributor and subsystem maintainer Martin Schwidefsky has been killed in an accident. "Martin was the most significant contributor to the initial s390 port of the Linux Kernel and later the maintainer of the s390 architecture backend. His technical expertise as well as his mentoring skills were outstanding. Martin was well known for his positive mindset and his willingness to help. He will be greatly missed."

The relationship between SUSE and the openSUSE community is currently under discussion as the community considers different options for how it wants to be organized and governed in the future. Among the options under consideration is the possibility of openSUSE setting up an entirely independent foundation, as it seeks greater autonomy and control over its own future and operations.

Security updates have been issued by Debian (drupal7 and jackson-databind), Fedora (checkstyle and gradle), openSUSE (qemu and xen), SUSE (ffmpeg, kvm, and ucode-intel), and Ubuntu (libraw and python-urllib3).

Damien Le Moal and Naohiro Aota led a combined storage and filesystem session at the 2019 Linux Storage, Filesystem, and Memory-Management Summit (LSFMM) on filesystem work that has been done for zoned block devices. These devices have multiple zones with different characteristics; usually there are zones that can only be written in sequential order as well as conventional zones that can be written in random order. The genesis of zoned block devices is shingled magnetic recording (SMR) devices, which were created to increase the capacity of hard disks, but at the cost of some flexibility.

In a combined filesystem and storage session at the 2019 Linux Storage, Filesystem, and Memory-Management Summit, Avri Altman wanted to discuss the "turbo-write" mode that is coming for Universal Flash Storage (UFS) devices. He wanted to introduce this new feature to assembled developers and to get some opinions on how to support this mode in the kernel.

Version 3.4 of the Bison parser generator is out. "A particular focus was put on improving the diagnostics, which are now colored by default, and accurate with multibyte input. Their format was also changed, and is now similar to GCC 9's diagnostics."

By the time Linus Torvalds released the 5.2-rc1 kernel prepatch and closed the merge window for this development cycle, 12,064 non-merge changesets had been pulled into the mainline repository — about 3,700 since our summary of the first "half" was written. Thus, as predicted, the rate of change did slow during the latter part of the merge window. That does not mean that no significant changes have been merged, though; read on for a summary of what else has been merged for 5.2.

Security updates have been issued by Debian (cups-filters, dhcpcd5, faad2, ghostscript, graphicsmagick, jruby, lemonldap-ng, and libspring-security-2.0-java), Fedora (gnome-desktop3, java-1.8.0-openjdk-aarch32, libu2f-host, samba, sqlite, webkit2gtk3, xen, and ytnef), Mageia (docker, flash-player-plugin, freeradius, libsndfile, libxslt, mariadb, netpbm, python-jinja2, tomcat-native, and virtualbox), openSUSE (kernel and ucode-intel), and SUSE (kernel, kvm, libvirt, nmap, and transfig).

Wired looks at the security issues stemming from the complexity of the Bluetooth standard. "Bluetooth has certainly been investigated to a degree, but researchers say that the lack of intense scrutiny historically stems again from just how involved it is to even read the standard, much less understand how it works and all the possible implementations. On the plus side, this has created a sort of security through obscurity, in which attackers have also found it easier to develop attacks against other protocols and systems rather than taking the time to work out how to mess with Bluetooth."

Linus has released the 5.2-rc2 kernel prepatch and closed the merge window for this development cycle. "Nothing particularly odd going on this merge window. I had some travel in the middle of it, but to offset that I had a new faster test-build setup, and most of the pull requests came in early (thank you) so my travels didn't actually end up affecting the merge window all that much."

The ever-increasing complexity of the software stacks we work with has given testing an important role. There was a recent intersection between the automated testing being done by the Yocto Project (YP) and a bug introduced into the Linux kernel that gives some insight into what the future holds and the potential available with this kind of testing.

Six new stable kernels have been released: 5.1.3, 5.0.17, 4.19.44, 4.14.120, 4.9.177, and 4.4.180. As usual, they contain important fixes throughout the kernel tree; users should upgrade.

Security updates have been issued by Debian (jquery), Fedora (kernel-headers, php-typo3-phar-stream-wrapper, and python3), openSUSE (qemu, ucode-intel, and xen), Red Hat (chromium-browser, java-1.8.0-ibm, and rh-python35-python-jinja2), SUSE (containerd, docker, docker-runc, go, go1.11, go1.12, golang-github-docker-libnetwork, evolution, graphviz, kernel, qemu, and systemd), and Ubuntu (libmediainfo, libvirt, and Wireshark).

Over the past four years, LWN has covered the Python Language Summit, but this year the Python Software Foundation (PSF) elected to go in a different direction, with coverage by A. Jesse Jiryu Davis on the PSF blog. Those reports are being gathered on a summit page; as of this writing there are two reports up with plenty more to come. "The Python Language Summit is a small gathering of Python language implementers, both the core developers of CPython and alternative Pythons, held on the first day of PyCon. The summit features short presentations from Python developers and community members, followed by longer discussions. The 2019 summit is the first held since Guido van Rossum stepped down as Benevolent Dictator for Life, replaced by a five-member Steering Council."

Even with radiators and fans, a system's CPUs can overheat. When that happens, the kernel's thermal governor will cap the maximum frequency of that CPU to allow it to cool. The scheduler, however, is not aware that the CPU's capacity has changed; it may schedule more work than optimal in the current conditions, leading to a performance degradation. Recently, Thara Gopinath did some research and posted a patch set to address this problem. The solution adds an interface to inform the scheduler about thermal events so that it can assign tasks better and thus improve the overall system performance.

Greg Kroah-Hartman has announced the release of the 3.18.140 stable kernel. "Note, this is the LAST 3.18.y release that I will be doing on kernel.org. I know it has been marked as End-of-Life for quite some time, but I have kept it alive due to a few million phones out there in the wild that depend on it, and can not move to a new kernel base due to them being stuck with a SoC vendor that does not work upstream. But, this does not mean the tree is dead, oh no, if only it were that easy..." He and others will be updating the kernel in the Android Open Source Project (AOSP) tree.

Security updates have been issued by CentOS (freeradius, kernel, libvirt, and qemu-kvm), Debian (intel-microcode, linux-4.9, and samba), Fedora (kernel, kernel-headers, memcached, microcode_ctl, php-pecl-imagick, and samba), Mageia (kernel, kernel-linus, kernel-tmb, and microcode), openSUSE (389-ds, bzip2, jakarta-commons-fileupload, kernel, and pacemaker), Red Hat (flash-plugin and ruby), Scientific Linux (kernel, libvirt, qemu-kvm, and ruby), Slackware (rdesktop), and Ubuntu (libvirt).