The BPF virtual machine within the kernel has seen a great deal of work over the last few years; as that has happened, its use has expanded to many different kernel subsystems. One of the objectives of that work in the past has been to make it safe to allow unprivileged users to load at least some types of BPF programs into the kernel. A recent discussion has made it clear, though, that the goal of opening up BPF to unprivileged users has been abandoned as unachievable, and that further work in that direction will not be accepted by the BPF maintainer.
Luis Chamberlain has announced the “kdevops” kernel-development framework. “I’m announcing the release of kdevops which aims at making setting up and testing the Linux kernel for any project as easy as possible. Note that setting up testing for a subsystem and testing a subsystem are two separate operations, however we strive for both. This is not a new test framework, it allows you to use existing frameworks, and set those frameworks up as easily can humanly be possible. It relies on a series of modern hip devops frameworks, it relies on ansible, vagrant and terraform, ansible roles through the Ansible Galaxy, and terraform modules.”
PHP is the Fortran of the world-wide web: it demonstrated the power of code embedded in web pages, but has since been superseded in many developers’ minds by more contemporary technologies. Even so, as with Fortran, there is far more PHP code out there than one might think, and PHP is still chosen for new projects. There is a certain amount of tension in the PHP development community between the need to maintain compatibility for large amounts of ancient code and the need to evolve the language to keep it relevant for current developers. That tension has now come into the open with a proposal to split PHP into two languages.
EPEL 8.0 is out. “EPEL stands for Extra Packages for Enterprise Linux and is a subcommunity of the Fedora and CentOS projects aimed at bringing a subset of packages out of Fedora releases ready to be used and installed on various Red Hat Enterprise Linux (RHEL).” Beyond the update to RHEL (and CentOS) 8, this release features a new faster-moving “playground” package stream and support for the s390 architecture.
For those interested in the details of how one kernel developer works: Greg Kroah-Hartman has documented his email workflow in great detail. “The ability to edit a single message directly within my email client is essential. I end up having to fix up changelog text, editing the subject line to be correct, fixing the mail headers to not do foolish things with text formats, and in some cases, editing the patch itself for when it is corrupted or needs to be fixed (I want a Linkedin skill badge for ‘can edit diff files by hand and have them still work’)”
Technologies like RDMA benefit from the ability to map file-backed pages into memory. This benefit extends to persistent-memory devices, where the backing store for the file can be mapped directly without the need to go through the kernel’s page cache. There is a fundamental conflict, though, between mapping a file’s backing store directly and letting the filesystem code modify that file’s on-disk layout, especially when the mapping is held in place for a long time (as RDMA is wont to do). The problem seems intractable, but there may yet be a solution in the form of this patch set (marked “V1,000,002”) from Ira Weiny.
GNU Radio is an extensive framework for software-defined radio development. The 3.8.0.0 release is finally available. “It’s the first minor release version since more than six years, not without pride this community stands to face the brightest future SDR on general purpose hardware ever had.”
One of these years, LWN will have a new accounting system based on free software. That transition has not yet happened, though, despite the expending of a fair amount of energy into researching alternatives. Your editor recently became aware of a system called Akaunting, so a look seemed worthwhile. This tool may have the features that some users want, but it seems clear that your editor’s quest is not done yet.
The Kubernetes community has posted the extensive results [PDF] of a security assessment performed earlier this year. “Overall, Kubernetes is a large system with significant operational complexity. The assessment team found configuration and deployment of Kubernetes to be non-trivial, with certain components having confusing default settings, missing operational controls, and implicitly defined security controls. Also, the state of the Kubernetes codebase has significant room for improvement. The codebase is large and complex, with large sections of code containing minimal documentation and numerous dependencies, including systems external to Kubernetes. There are many cases of logic re-implementation within the codebase which could be centralized into supporting libraries to reduce complexity, facilitate easier patching, and reduce the burden of documentation across disparate areas of the codebase.”
The Spectre v1 hardware vulnerability is often characterized as allowing array bounds checks to be bypassed via speculative execution. While that is true, it is not the full extent of the shenanigans allowed by this particular class of vulnerabilities. For a demonstration of that fact, one need look no further than the “SWAPGS vulnerability” known as CVE-2019-1125 to the wider world or as “Grand Schemozzle” to the select group of developers who addressed it in the Linux kernel.
Lars Knoll describes the goals for the next major version of the Qt graphics toolkit. “Qt has been growing a lot over the last years, to the point where delivering a new version of it is a major undertaking. With Qt 6 there is an opportunity to restructure our product offering and have a smaller core product that contains the essential frameworks and tooling. We will use the market place to deliver our add-on frameworks and tools, not as a tightly coupled bundle with the core Qt product.”
The Compact C Type Format (CTF) is a way of representing information about a binary program; it can be seen as a simpler alternative to the widely used DWARF format. While CTF has been around for some years, it has not seen much use in the Linux world. According to Elena Zannoni, who talked about CTF at the 2019 Open Source Summit Japan, that situation may be about to change; work is underway to bring CTF support to the GNU tools shipped universally with Linux systems.
Freedombone 4.0 is available. Freedombone is a distribution (based on Debian 10) focused on the hosting network services under one’s own control on home servers. “There is no freedom without freedom of association. That is, having the ability to define who you are and what kind of community you want to live in. This release includes Community Networks as an initial step towards networks run by and for the people who use them.” Support for the Wireguard VPN has been added, but the “Fediverse” applications (GNU Social, PostActiv, and Pleroma) have been removed as being too hard to manage.
Freedombone 4.0 is available. Freedombone is a distribution (based on Debian 10) focused on the hosting network services under one’s own control on home servers. “There is no freedom without freedom of association. That is, having the ability to define who you are and what kind of community you want to live in. This release includes Community Networks as an initial step towards networks run by and for the people who use them.” Support for the Wireguard VPN has been added, but the “Fediverse” applications (GNU Social, PostActiv, and Pleroma) have been removed as being too hard to manage.
The 5.3-rc3 kernel prepatch is out. “Interesting. Last Sunday, rc2 was fairly large to match the biggish merge window, but this last week has actually been quite calm, and rc3 is actually smaller than usual, and smaller than rc2 was”
The seccomp() mechanism is notoriously difficult to use. It also turns out to be easy to break unintentionally, as the development community discovered when a timekeeping change meant to address the year-2038 problem created a regression for seccomp() users in the 5.3 kernel. Work is underway to mitigate the problem for now, but seccomp() users on 32-bit systems are likely to have to change their configurations at some point.
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