Language Selection

English French German Italian Portuguese Spanish

Linux

LWN on Linux: LTS, API, Pointer Leaks and Linux Plumbers Conference (LPC)

Filed under
Linux
  • Cramming features into LTS kernel releases

    While the 4.14 development cycle has not been the busiest ever (12,500 changesets merged as of this writing, slightly more than 4.13 at this stage of the cycle), it has been seen as a rougher experience than its predecessors. There are all kinds of reasons why one cycle might be smoother than another, but it is not unreasonable to wonder whether the fact that 4.14 is a long-term support (LTS) release has affected how this cycle has gone. Indeed, when he released 4.14-rc3, Linus Torvalds complained that this cycle was more painful than most, and suggested that the long-term support status may be a part of the problem. A couple of recent pulls into the mainline highlight the pressures that, increasingly, apply to LTS releases.

    As was discussed in this article, the 4.14 kernel will include some changes to the kernel timer API aimed at making it more efficient, more like contemporary in-kernel APIs, and easier to harden. While API changes are normally confined to the merge window, this change was pulled into the mainline for the 4.14-rc3 release. The late merge has led to a small amount of grumbling in the community.

  • Improving the kernel timers API

    The kernel's timer interface has been around for a long time, and its API shows it. Beyond a lack of conformance with current in-kernel interface patterns, the timer API is not as efficient as it could be and stands in the way of ongoing kernel-hardening efforts. A late addition to the 4.14 kernel paves the way toward a wholesale change of this API to address these problems.

  • What's the best way to prevent kernel pointer leaks?

    An attacker who seeks to compromise a running kernel by overwriting kernel data structures or forcing a jump to specific kernel code must, in either case, have some idea of where the target objects are in memory. Techniques like kernel address-space layout randomization have been created in the hope of denying that knowledge, but that effort is wasted if the kernel leaks information about where it has been placed in memory. Developers have been plugging pointer leaks for years but, as a recent discussion shows, there is still some disagreement over the best way to prevent attackers from learning about the kernel's address-space layout.

    There are a number of ways for a kernel pointer value to find its way out to user space, but the most common path by far is the printk() function. There are on the order of 50,000 printk() calls in the kernel, any of which might include the value of a kernel pointer. Other places in the kernel use the underlying vsprintf() mechanism to format data for virtual files; they, too, often leak pointer values. A blanket ban on printing pointer values could solve this problem — if it could be properly enforced — but it would also prevent printing such values when they are really needed. Debugging kernel problems is one obvious use case for printing pointers, but there are others.

  • Continuous-integration testing for Intel graphics

    Two separate talks, at two different venues, give us a look into the kinds of testing that the Intel graphics team is doing. Daniel Vetter had a short presentation as part of the Testing and Fuzzing microconference at the Linux Plumbers Conference (LPC). His colleague, Martin Peres, gave a somewhat longer talk, complete with demos, at the X.Org Developers Conference (XDC). The picture they paint is a pleasing one: there is lots of testing going on there. But there are problems as well; that amount of testing runs afoul of bugs elsewhere in the kernel, which makes the job harder.

    Developing for upstream requires good testing, Peres said. If the development team is not doing that, features that land in the upstream kernel will be broken, which is not desirable. Using continuous-integration (CI) along with pre-merge testing allows the person making a change to make sure they did not break anything else in the process of landing their feature. That scales better as the number of developers grows and it allows developers to concentrate on feature development, rather than bug fixing when someone else finds the problem. It also promotes a better understanding of the code base; developers learn more "by breaking stuff", which lets them see the connections and dependencies between different parts of the code.

Intel Linux and GCC Work

Filed under
Development
GNU
Linux
  • Intel Begins Landing GFNI Support In GCC 8

    Intel compiler engineers have begun landing "GFNI" support within the GNU Compiler Collection as one of the new ISA extensions not expected until the Icelake processor debut.

  • Control-Flow Enforcement Technology Begins To Land In GCC 8

    Intel Control-flow Enforcement Technology (CET) support has begun landing within the GNU Compiler Collection (GCC) for this code safety feature.

    Patches have been in the works for several months while now the start of the patches are being merged to mainline. Coincidentally, at the same time Intel is also landing their GFNI instruction patches in GCC as well.

  • Intel Continues Landing New i915 DRM Features For Linux 4.15

    Jani Nikula has sent in another drm-intel-next update for David Airlie's DRM-Next tree. They continue prepping more updates to their Direct Rendering Manager (DRM) for targeting the upcoming Linux 4.15 cycle.

    There have already been several Intel "i915" DRM driver updates queued in DRM-Next for this new kernel version. Past pulls have included marking Coffeelake graphics as stable, continued Cannonlake "Gen 10" graphics enablement, various display improvements, and quite a lot of other low-level code improvements.

More “Linux On Galaxy”

Filed under
GNU
Linux

NODE Handheld Linux Terminal Version 3

Filed under
GNU
Linux
Hardware

YouTuber NODE has released a new video unveiling his third generation Handheld Linux Terminal which builds on the features from the previous creations and is once again fantastically awesome.

Check out the video below to learn more about the Handheld Linux Terminal Version 3 powered by a Raspberry Pi 3 mini PC. Great job NODE.

Read more

Anarchy Linux Dispels Fear of Arch

Filed under
Linux
Reviews

Arch-Anywhere/Anarchy Linux is one of the nicest Arch-based distributions I have encountered. However, Anarchy Linux still requires familiarity with terminology and processes that usually are not needed to install Linux distros from a fully-functioning live session installation disk. Not having a demo mode to preview how the OS runs on your particular hardware can be a time-consuming setback.

However, once you have Anarchy Linux up and running, it will give you a very pleasing computing experience. Much of what happens after installation depends on the desktop environment you selected.

If you have a desktop preference or prefer one of the included window manager environments instead, you can forget about the sullied reputation that comes with Arch Linux distros. For many reasons, Anarchy Linux is a winning choice.

Read more

Running Android on Top of a Linux Graphics Stack

Filed under
Android
Linux
Interviews

Traditional Linux graphics systems (like X11) mostly did not use planes. But modern graphics systems like Android and Wayland can take full advantage of it.

Android has the most mature implementation of plane support in HWComposer, and its graphics stack is a bit different from the usual Linux desktop graphics stack. On desktops, the typical compositor just uses the GPU for all composition, because this is the only thing that exists on the desktop.

Most embedded and mobile chips have specialized 2D composition hardware that Android is designed around. The way this is done is by dividing the things that are displayed into layers, and then intelligently feeding the layers to hardware that is optimized to handle layers. This frees up the GPU to work on the things you actually care about, while at the same time, it lets hardware that is more efficient do what it does best.

Read more

Why and how you should switch to Linux

Filed under
Linux

When you start comparing computers, you probably pit Windows against macOS—but Linux rarely gets a mention. Still, this lesser-known operating system has a strong and loyal following. That's because it offers a number of advantages over its competitors.

Whether you're completely new to Linux or have dabbled with it once or twice already, we want you to consider running it on your next laptop or desktop—or alongside your existing operating system. Read on to decide if it's time to make the switch.

Read more

Purism disables Intel's flawed Management Engine on Linux-powered laptops

Filed under
Linux

LINUX PC MAKER Purism has devised a process to disable the flawed Intel Management Engine.

The company's line of Librem laptops, which run flexible open-source firmware Coreboot, are now running with Intel's management service completely disabled.

As a core part of Intel Active Management Technology (AMT), the management engine is present in all the company's CPUs and is capable of powering a computer, even when it is powered off.

Read more

Linux Tiny Box PCs and DeX

Filed under
GNU
Linux
Hardware
  • Linux Tiny Box PCs: Quad-core i.MX6 Dual Lite

    Kingdy's new ultra-compact tiny embedded platform for space limited solution, based on the ARM Cortex-A9TM iMX6 Dual Lite / Quad Core processor, delivers optimum I/O design for maximum connectivity with Pre-install Yocto 1.8 on eMMC.

  • Samsung to Give Linux Desktop Experience to Smartphone Users

    Samsung on Thursday announced a new app, Linux on Galaxy, designed to work with its DeX docking station to bring a full Linux desktop experience to Galaxy Note8, Galaxy S8 and S8+ smartphone users.

    Samsung earlier this year introduced DeX, a docking station that connects to a monitor to give Galaxy smartphone users a desktop experience.

Syndicate content

More in Tux Machines

Games Leftovers

Android Leftovers

HTC U11 Life (Android One) review: Keep it simple

Android One has arrived in Europe, and HTC is one of the first manufacturers to ship an affordable, Google-branded phone. The Android One badge made its debut in India and parts of Asia, as Google emphasized quality software on super-cheap hardware. But with its latest round of "One" handsets, the prices are higher, the products more premium, and the hand on the software rudder a little firmer. The Android One U11 Life — unlike the T-Mobile U.S. version we reviewed separately, running HTC Sense — runs Android 8.0 Oreo out of the box, and comes with the promise of timely updates to future versions. It takes the fundamentals of HTC's flagship phone and downscales it into a smaller size, while trimming the specs back to the essentials. There's a Snapdragon 630 processor — Qualcomm's latest mid-ranger, and the successor to the very capable 625/626 — along with 3GB or 4GB of RAM, and 32 or 64GB of storage, plus microSD. I've been using the 3/32GB model for the past couple of weeks, however the UK will be getting the more capacious 4/64GB model when it goes on sale. Read more

The power of open source: Why GitLab's move to a Developer Certificate of Origin benefits the developer community

Over the past few years, open source software has transformed the way enterprises operate and ship code. In an era where companies are striving to deliver the next best application, enterprises are turning to the sea of open source contributors to create projects faster and more effectively than ever before. For instance, 65 percent of companies surveyed in The Black Duck Future of Open Source Survey reveal they are contributing to open source projects – with 59 percent doing so to gain a competitive edge. As open source continues to have a positive influence on software development, it’s important for developers to continue to participate in and contribute to open source projects. Read more