LWN Articles About Linux (Kernel)
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Identifying dependencies used via dlopen()
The recent XZ backdoor has sparked a lot of discussion about how the open-source community links and packages software. One possible security improvement being discussed is changing how projects like systemd link to dynamic libraries that are only used for optional functionality: using dlopen() to load those libraries only when required. This could shrink the attack surface exposed by dependencies, but the approach is not without downsides — most prominently, it makes discovering which dynamic libraries a program depends on harder. On April 11, Lennart Poettering proposed one way to eliminate that problem in a systemd RFC on GitHub.
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Completing the EEVDF scheduler
The Earliest Virtual Deadline First (EEVDF) scheduler was merged as an option for the 6.6 kernel. It represents a major change to how CPU scheduling is done on Linux systems, but the EEVDF front has been relatively quiet since then. Now, though, scheduler developer Peter Zijlstra has returned from a long absence to post a patch series intended to finish the EEVDF work. Beyond some fixes, this work includes a significant behavioral change and a new feature intended to help latency-sensitive tasks.
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A tale of two troublesome drivers [Ed: The LF treats GNU/Linux like it is "just Linux" and Linux is "the kernel". Reality is, GNU/Linux is the OS and Linux is just the kernel.]
The kernel project merges dozens of drivers with every development cycle, and almost every one of those drivers is entirely uncontroversial. Occasionally, though, a driver submission raises wider questions, leading to lengthy discussion and, perhaps, opposition. That is currently the case with two separate drivers, both with ties to the networking subsystem. One of them is hung up on questions of whether (and how) all device functionality should be made available to user space, while the other has run into turbulence because it drives a device that is unobtainable outside of a single company.
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Cleaning up after BPF exceptions
Kumar Kartikeya Dwivedi has been working to add support for exceptions to BPF since mid-2023. In July, Dwivedi posted the first patch set in this effort, which adds support for basic stack unwinding. In February 2024, he posted the second patch set aimed at letting the kernel release resources held by the BPF program when an exception occurs. This makes exceptions usable in many more contexts.