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LWN has had a number of articles on immutable distributions, such as Bluefin and Bazzite, in recent years. These distributions have taken a variety of approaches, including using rpm-ostree, filesystem snapshots, and bootable container (bootc) images. But those approaches, especially the latter, lead to extra complexity for a user attempting to install new software, instead of just using the existing package manager. AshOS (Any Snapshot Hierarchical OS) is an experimental AGPL-3-licensed "meta-distribution" that tried a different approach more in line with traditional package management. Although the project is no longer updated, it remains usable, and can still shed some light on a potential alternate path for users worried about adopting bootc-based approaches.

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The io_uring subsystem is more than an asynchronous I/O interface for Linux; it is, for all practical purposes, an independent system-call API. It has enabled high-performance applications, but it also brings challenges for code built around classic, Unix-style system calls. For example, the seccomp() sandboxing mechanism does not work with it, causing applications using seccomp() to disable io_uring outright. Io_uring maintainer Jens Axboe is seeking to improve that situation with a rapidly evolving patch series adding a new restrictive mechanism to that subsystem.

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While there are several rootkits that target Linux, they have so far not fully embraced the open-source ethos typical of Linux software. Luckily, Matheus Alves has been working to remedy this lack by creating an open-source rootkit called Singularity for Linux systems. Users who feel their computers are too secure can install the Singularity kernel module in order to allow remote code execution, disable security features, and hide files and processes from normal administrative tools. Despite its many features, Singularity is not currently known to be in use in the wild — instead, it provides security researchers with a testbed to investigate new detection and evasion techniques.

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Al Viro does not often stray outside of the core virtual filesystem area; when he does, it is usually worthy of note. Recently, he wandered into memory management with this patch series to the slab allocator and some of its users. Kernel developers will often put considerable effort into small optimizations, but it is still interesting to look at just how much effort has gone toward the purpose of avoiding a single pointer dereference in some memory-allocation hot paths.

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Lossless data compression is an important tool for reducing the storage requirements of the world's ever-growing data sets. Yann Collet developed the LZ4 algorithm and designed the Zstandard (or Zstd) algorithm; he came to the 2025 Open Source Summit Japan in Tokyo to talk about where data compression goes from here. It turns out that we have reached a point where general-purpose algorithms are only going to provide limited improvement; for significant increases in compression, while keeping computation costs within reason for data-center use, turning to format-specific techniques will be needed.

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The Debian GNOME team would like to remove the GTK 2 graphics toolkit, which has been unmaintained upstream for more than five years, and ship Debian 14 ("forky") without it. As one might expect, however, there are those who would like to find a way to keep it. Despite its age and declared obsolescence, quite a few Debian packages still depend on GTK 2. Many of those applications are unlikely to be updated, and users are not eager to give them up. Discussion about how to handle this is ongoing; it seems likely that Debian developers will find some way to continue supporting applications that require GTK 2, but users may have to look outside official Debian repositories.

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Quality-of-service (QoS) mechanisms attempt to prioritize some processes (or network traffic, disk I/O, etc.) over others in order to meet a system's performance goals. This is a difficult topic to handle in the world of Linux, where workloads, hardware, and user expectations vary wildly. Qais Yousef spoke at the 2025 Linux Plumbers Conference, alongside his collaborators John Stultz, Steven Rostedt, and Vincent Guittot, about their plans for introducing a high-level QoS API for Linux in a way that leaves end users in control of its configuration. The talk focused specifically on a QoS mechanism for the scheduler, to prioritize access to CPU resources differently for different kinds of processes. (slides; video)

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In open-source circles there are many situations, such as bug reports, demos, and tutorials, when one might want to provide a play-by-play of a session in one's terminal. The asciinema project provides a set of tools to do just that. Its tools let users record, edit, and share terminal sessions in a text-based format that has quite a few advantages compared to making and sharing videos of terminal sessions. For example, it is easy to use, offers the ability to search text from recorded sessions, and allows users to copy and paste directly from the recording.

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The READ_ONCE() and WRITE_ONCE() macros are heavily used within the kernel; there are nearly 8,000 call sites for READ_ONCE(). They are key to the implementation of many lockless algorithms and can be necessary for some types of device-memory access. So one might think that, as the amount of Rust code in the kernel increases, there would be a place for Rust versions of these macros as well. The truth of the matter, though, is that the Rust community seems to want to take a different approach to concurrent data access.

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