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The traditional structure of a compiler forms a pipeline — parsing, type-checking, optimization, and code-generation, usually in that order. But modern programming languages have requirements that are ill-suited to such a design. Increasingly, compilers are moving toward other designs in order to support incremental compilation and low-latency responses for uses like integration into IDEs. Rust ha

Alejandro Colomar, who has been maintaining the Linux man pages for the last four years, has announced that he will have to stop that work. I've been doing it in my free time, and no company has sponsored that work at all. At the moment, I cannot sustain this work economically any more, and will temporarily and indefinitely stop working on this project. If any company has interests in the future o

LWN has covered BPF since its initial introduction to Linux, usually through the lens of the newest developments; this can make it hard to view the whole picture. BPF provides a way to extend a running kernel, without having to recompile and reboot. It does this in a safe way, so that malicious BPF programs cannot crash a running kernel, thanks to the BPF verifier. So how does the verifier actuall

The mseal() system call allows a process to prevent any future changes to portions of its address space (thus "sealing" them); it was patterned after the mimmutable() system call in OpenBSD. mseal() generated a lot of discussion, but it was finally merged for the upcoming 6.10 kernel release. While mseal() was initially aimed at securing the Chrome browser, the hope was that it would be useful els

For several years, contributors to the Rust project have been working to improve support for asynchronous code. The benefits of these efforts are not confined to asynchronous code, however. Members of the Rust community have been working toward adding explicit existential types to Rust since 2017. Existential types are not a common feature of programming languages (something the RFC acknowledges),

The Rust programming language differs from C in many ways; those differences tend to be what users admire in the language. But those differences can also lead to an impedance mismatch when Rust code is integrated into a C-dominated system, and it can be even worse in the kernel, which is not a typical C program. Memory models are a case in point. A programming language's view of memory is sufficie

Versions 5.6.0 and 5.6.1 of the XZ compression utility and library were shipped with a backdoor that targeted OpenSSH. Andres Freund discovered the backdoor by noticing that failed SSH logins were taking a lot of CPU time while doing some micro-benchmarking, and tracking down the backdoor from there. It was introduced by XZ co-maintainer "Jia Tan" — a probable alias for person or persons unknown.

Binbin Zhu BinBin Wang, of Tencent, is responsible for nearly 25% of the commits to the project. Some of the contributors without a readily identifiable employer surely are Redis employees, but it's clear that the company has not been working alone. (Note that some single-digit contributors were omitted.) Changing distribution model So it should be apparent that code contribution is beside the poi

As the Rust-for-Linux project advances, the kernel is gradually accumulating abstraction layers that enable Rust code to interface with the existing C code. As the discussion around the set of filesystem abstractions posted by Wedson Almeida Filho in December shows, though, there is some tension between two approaches to the design of those abstractions. The approach favored by most of the kernel'

December 28, 2023 This article was contributed by Thomas Zimmermann Displaying an application's graphical output onto the screen requires compositing and mode setting that are correctly synchronized among the various pieces, with low overhead. In this second and final article in the series, we will look at those pieces of the Linux graphics stack. In the first installment, we followed the path of

December 19, 2023 This article was contributed by Thomas Zimmermann Linux graphics developers often speak of modern Linux graphics when they refer to a number of individual software components and how they interact with each other. Among other things, it's a mix of kernel-managed display resources, Wayland for compositing, accelerated 3D rendering, and decidedly not X11. In a two-part series, we w

December 15, 2023 This article was contributed by Ronja Koistinen The gccrs project is an ambitious effort started in 2014 to implement a Rust compiler within The GNU Compiler Collection (GCC). Even though the task is far from complete, progress has been made since LWN's previous coverage, according to reports from the project. Meanwhile, another hybrid and more mature approach to GCC Rust code ge

Rust has been a prominent topic at the Kernel Maintainers Summit for the last couple of years, and the 2023 meeting continued that tradition. As Rust-for-Linux developer Miguel Ojeda noted at the beginning of the session dedicated to the topic, the level of interest in using Rust for kernel development has increased significantly over the last year. But Rust was explicitly added to Linux as an exp

Containers and virtual machines on Linux communicate with the world via virtual network devices. This arrangement makes the full power of the Linux networking stack available, but it imposes the full overhead of that stack as well. Often, the routing of this networking traffic can be handled with relatively simple logic; the BPF-programmable network device, which was merged for the 6.7 kernel rele

No-GIL mode coming for Python Posted Jul 28, 2023 23:51 UTC (Fri) by tialaramex (subscriber, #21167) [Link] (12 responses) Just over six months ago I wrote this: https://lwn.net/Articles/919666/ "this PEP needs to specify a mechanism which ensures if you have a 2022 C library which was fine because of the GIL, and a 2022 Python program which used that C library, you cannot set everything on fire b

Red Hat has announced that public source releases will be restricted to CentOS Stream going forward: As the CentOS Stream community grows and the enterprise software world tackles new dynamics, we want to sharpen our focus on CentOS Stream as the backbone of enterprise Linux innovation. We are continuing our investment in and increasing our commitment to CentOS Stream. CentOS Stream will now be th

In the fast-moving open-source world, programs can come and go quickly; a tool that has many users today can easily be eclipsed by something better next week. Even in this environment, though, some programs endure for a long time. As an example, consider the PostgreSQL database system, which traces its history back to 1986. Making fundamental changes to a large code base with that much history is

May 2, 2023 This article was contributed by Koen Vervloesem Linters are tools that analyze a program's source code to detect various problems such as syntax errors, programming mistakes, style violations, and more. They are important for maintaining code quality and readability in a project, as well as for catching bugs early in the development cycle. Last year, a new Python linter appeared: Ruff.

April 12, 2023 This article was contributed by Lars Wirzenius My name is Lars Wirzenius, and I was there when Linux started. Linux is now a global success, but its beginnings were rather more humble. These are my memories of the earliest days of Linux, its creation, and the start of its path to where it is today. I started my computer science studies at the University of Helsinki in the fall of 19

March 28, 2023 This article was contributed by Bradley Moodley Canonical recently announced that it will no longer ship Flatpak as part of its default installation for the various official Ubuntu flavors, which is in keeping with the practices of the core Ubuntu distribution. The Flatpak package format has gained popularity among Linux users for its convenience and ease of use. Canonical will focu

Nolibc: a minimal C-library replacement shipped with the kernel The kernel project does not host much user-space code in its repository, but there are exceptions. One of those, currently found in the tools/include/nolibc directory, has only been present since the 5.1 release. The nolibc project aims to provide minimal C-library emulation for small, low-level workloads. Read on for an overview of n

It was only a matter of time before somebody found a way to inject BPF into the CPU scheduler. This patch series, posted by Tejun Heo and containing work by David Vernet, Josh Don, and Barret Rhoden, does exactly that. The cover letter covers the motivation behind this work in detail: One of our main goals was to lower the barrier to entry for experimenting with the scheduler. sched_ext provides e

Did you know...?LWN.net is a subscriber-supported publication; we rely on subscribers to keep the entire operation going. Please help out by buying a subscription and keeping LWN on the net. Among the many quirks that make the C language so charming is the set of behaviors that it does not define; these include whether a char variable is a signed quantity or not. The distinction often does not mak

There have been a lot of significant changes merged into the mainline for the 6.1 release, but one of the changes that has received the most attention will also have the least short-term effect for users of the kernel: the introduction of support for the Rust programming language. No system with a production 6.1 kernel will be running any Rust code, but this change does give kernel developers a ch

LWN.net needs you!Without subscribers, LWN would simply not exist. Please consider signing up for a subscription and helping to keep LWN publishing The traditional mechanism for launching a program in a new process on Unix systems—forking and execing—has been with us for decades, but it is not really the most efficient of operations. Various alternatives have been tried along the way but have not

Did you know...?LWN.net is a subscriber-supported publication; we rely on subscribers to keep the entire operation going. Please help out by buying a subscription and keeping LWN on the net. The idea of being able to write kernel code in the Rust language has a certain appeal, but it is hard to judge how well that would actually work in the absence of examples to look at. Those examples, especiall

Did you know...?LWN.net is a subscriber-supported publication; we rely on subscribers to keep the entire operation going. Please help out by buying a subscription and keeping LWN on the net. Docker and other container engines can greatly simplify many aspects of deploying a server-side application, but numerous applications consist of more than one container. Managing a group of containers only ge