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LWN.net is a comprehensive source of news and opinions from and about the Linux community. This is the main LWN.net feed, listing all articles which are posted to the site front page.
Updated: 5 hours 39 min ago

[$] Relief for retpoline pain

Friday 14th of December 2018 10:27:25 PM
Indirect function calls — calls to a function whose address is stored in a pointer variable — have never been blindingly fast, but the Spectre hardware vulnerabilities have made things far worse. The indirect branch predictor used to speed up indirect calls in the CPU can no longer be used, and performance has suffered accordingly. The "retpoline" mechanism was a brilliant hack that proved faster than the hardware-based solutions that were tried at the beginning. While retpolines took a lot of the pain out of Spectre mitigation, experience over the last year has made it clear that they still hurt. It is thus not surprising that developers have been looking for alternatives to retpolines; several of them have shown up on the kernel lists recently.

Security updates for Friday

Friday 14th of December 2018 03:55:58 PM
Security updates have been issued by CentOS (ghostscript, git, java-1.7.0-openjdk, java-11-openjdk, kernel, NetworkManager, python-paramiko, ruby, sos-collector, thunderbird, and xorg-x11-server), Debian (gcc-4.9), and SUSE (amanda, ntfs-3g_ntfsprogs, and tiff).

[$] Linux in mixed-criticality systems

Thursday 13th of December 2018 05:23:54 PM
The Linux kernel is generally seen as a poor fit for safety-critical systems; it was never designed to provide realtime response guarantees or to be certifiable for such uses. But the systems that can be used in such settings lack the features needed to support complex applications. This problem is often solved by deploying a mix of computers running different operating systems. But what if you want to support a mixture of tasks, some safety-critical and some not, on the same system? At a talk given at LinuxLab 2018, Claudio Scordino described an effort to support this type of mixed-criticality system.

A set of stable kernels

Thursday 13th of December 2018 04:18:15 PM
Greg Kroah-Hartman has released stable kernels 4.19.9, 4.14.88, 4.9.145, 4.4.167, and 3.18.129. They all contain important fixes and users should upgrade.

Security updates for Thursday

Thursday 13th of December 2018 04:10:19 PM
Security updates have been issued by Debian (firefox-esr), Fedora (singularity), openSUSE (compat-openssl098, cups, firefox, mozilla-nss, and xen), and SUSE (cups, exiv2, ghostscript, and git).

[$] LWN.net Weekly Edition for December 13, 2018

Thursday 13th of December 2018 12:42:02 AM
The LWN.net Weekly Edition for December 13, 2018 is available.

[$] DMA and get_user_pages()

Wednesday 12th of December 2018 04:55:28 PM

In the RDMA microconference of the 2018 Linux Plumbers Conference (LPC), John Hubbard, Dan Williams, and Matthew Wilcox led a discussion on the problems surrounding get_user_pages() (and friends) and the interaction with DMA. It is not the first time the topic has come up, there was also a discussion about it at the Linux Storage, Filesystem, and Memory-Management Summit back in April. In a nutshell, the problem is that multiple parts of the kernel think they have responsibility for the same chunk of memory, but they do not coordinate their activities; as might be guessed, mayhem can sometimes ensue.

The x32 subarchitecture may be removed

Wednesday 12th of December 2018 04:52:42 PM
The x32 subarchitecture is a software variant of x86-64; it runs the processor in the 64-bit mode, but uses 32-bit pointers and arithmetic. The idea is to get the advantages of x86-64 without the extra memory usage that goes along with it. It seems, though, that x32 is not much appreciated; few distributions support it and the number of users appears to be small. So now Andy Lutomirski is proposing its eventual removal:

I propose that we make CONFIG_X86_X32 depend on BROKEN for a release or two and then remove all the code if no one complains. If anyone wants to re-add it, IMO they're welcome to do so, but they need to do it in a way that is maintainable.

If there are x32 users out there, now would be a good time for them to speak up.

Security updates for Wednesday

Wednesday 12th of December 2018 03:46:33 PM
Security updates have been issued by Arch Linux (chromium, firefox, lib32-openssl, lib32-openssl-1.0, openssl, openssl-1.0, texlive-bin, and wireshark-cli), Fedora (perl), openSUSE (pdns), Oracle (kernel), Red Hat (kernel), Slackware (mozilla), SUSE (kernel, postgresql10, qemu, and xen), and Ubuntu (firefox, freerdp, freerdp2, pixman, and poppler).

Git 2.20.0 released

Wednesday 12th of December 2018 08:49:27 AM
Git 2.20.0 is out. Changes include interdiff generation support in git format-patch, an improved ability to cope with corrupted patches in git am, a number of performance and usability improvements, and more.

Firefox 64 released

Tuesday 11th of December 2018 07:49:15 PM
The Mozilla Blog takes a look at the Contextual Feature Recommender (CFR) in Firefox 64. "Aimed at people who are looking to get more out of their online experience or ways to level up. CFR is a system that proactively recommends Firefox features and add-ons based on how you use the web. For example, if you open multiple tabs and repeatedly use these tabs, we may offer a feature called “Pinned Tabs” and explain how it works. Firefox curates the suggested features and notifies you. With today’s release, we will start to rollout with three recommended extensions which include: Facebook Container, Enhancer for YouTube and To Google Translate. This feature is available for US users in regular browsing mode only. They will not appear in Private Browsing mode. Also, Mozilla does NOT receive a copy of your browser history. The entire process happens locally in your copy of Firefox." The release notes contain more details about this release.

[$] Large files with Git: LFS and git-annex

Tuesday 11th of December 2018 07:43:47 PM

Git does not handle large files very well. While there is work underway to handle large repositories through the commit graph work, Git's internal design has remained surprisingly constant throughout its history, which means that storing large files into Git comes with a significant and, ultimately, prohibitive performance cost. Thankfully, other projects are helping Git address this challenge. This article compares how Git LFS and git-annex address this problem and should help readers pick the right solution for their needs.

Security updates for Tuesday

Tuesday 11th of December 2018 04:14:41 PM
Security updates have been issued by Debian (php7.0), Fedora (keepalived, kernel, kernel-headers, kernel-tools, mingw-uriparser, and uriparser), openSUSE (pdns-recursor), Oracle (kernel), SUSE (compat-openssl098, glibc, java-1_8_0-ibm, kernel, opensc, python, python-base, python-cryptography, python-pyOpenSSL, samba, and soundtouch), and Ubuntu (cups).

[$] Measuring container security

Tuesday 11th of December 2018 02:55:51 PM

There are a lot of claims regarding the relative security of containers versus virtual machines (VMs), but there has been little in the way of actually trying to measure those differences. James Bottomley gave a talk in the refereed track of the 2018 Linux Plumbers Conference (LPC) that described work that targets filling in that gap. He and his colleagues have come up with a measure that, while not perfect, gives a starting point for further efforts.

Nextcloud 15 released

Tuesday 11th of December 2018 08:35:10 AM
Version 15 of the Nextcloud productivity and communications platform is out. New features include Mastodon integration, two-factor authentication, a number of user-interface improvements, and more.

Hutterer: Understanding HID report descriptors

Tuesday 11th of December 2018 08:19:31 AM
For those who would like a deeper understanding of how the human interface device (HID) protocol works, Peter Hutterer has posted a detailed overview. "Originally HID was designed to work over USB. But just like Shrek the technology world is obsessed with layers so these days HID works over different transport layers. HID over USB is what your mouse uses, HID over i2c may be what your touchpad uses. HID works over Bluetooth and it's celebrity-diet version BLE. Somewhere, someone out there is very slowly moving a mouse pointer by sending HID over carrier pigeons just to prove a point. Because there's always that one guy."

[$] A filesystem corruption bug breaks loose

Monday 10th of December 2018 05:58:42 PM
Kernel bugs can have all kinds of unfortunate consequences, from inconvenient crashes to nasty security vulnerabilities. Some of the most feared bugs, though, are those that corrupt data in filesystems. The losses imposed on users can be severe, and the resulting problems may not be noticed for a long time, making recovery difficult. Filesystem developers, knowing that they will have to face their users in the real world, go to considerable effort to prevent this kind of bug from finding its way into a released kernel. A recent failure in that regard raises a number of interesting questions about how kernel development is done.

Security updates for Monday

Monday 10th of December 2018 03:57:17 PM
Security updates have been issued by Debian (chromium-browser and lxml), Fedora (cairo, hadoop, and polkit), Mageia (tomcat), openSUSE (apache2-mod_jk, Chromium, dom4j, ImageMagick, libgit2, messagelib, ncurses, openssl-1_0_0, otrs, pam, php5, php7, postgresql10, rubygem-activejob-5_1, tiff, and tomcat), Red Hat (chromium-browser and rh-git218-git), Slackware (php), SUSE (audiofile, cri-o and kubernetes packages, cups, ImageMagick, libwpd, SMS3.2, and systemd), and Ubuntu (lxml).

Kernel prepatch 4.20-rc6

Monday 10th of December 2018 07:52:47 AM
The 4.20-rc6 kernel prepatch is out for testing. "Most of it looks pretty small and normal. Would I have preferred for there to be less churn? Yes. But it's certainly smaller than rc5 was, so we're moving in the right direction, and we have at least one more rc to go."

More stable kernel updates

Saturday 8th of December 2018 06:34:40 PM
The stable kernel process continues to churn out releases; 4.19.8, 4.14.87, and 4.9.144 are now available with another set of important fixes.

More in Tux Machines

today's leftovers

OSS Leftovers

  • #RecruitmentFocus: Open source skills in high demand
    The unemployment rate in South Africa rose to 27.5% in the third quarter of 2018, while the demand for skills remains high - leaving an industry conundrum that is yet to be solved. According to SUSE, partnerships that focus on upskilling graduates and providing real-work skills, as well as placement opportunities - could be exactly what the industry in looking for.
  • Stable: not moving vs. not breaking
    There are two terms that brings a heavy controversy in the Open Source world: support and stable. Both of them have their roots in the “old days” of Open Source, where its commercial impact was low and very few companies made business with it. You probably have read a lot about maintenance vs support. This controversy is older. I first heard of it in the context of Linux based distributions. Commercial distribution had to put effort in differentiating among the two because in Open SOurce they were used indistictly but not in business. But this post is about the adjectivet stable…
  • Cameron Kaiser: A thank you to Ginn Chen, whom Larry Ellison screwed
    Periodically I refresh my machines by dusting them off and plugging them in and running them for a while to keep the disks spinnin' and the caps chargin'. Today was the day to refurbish my Sun Ultra-3, the only laptop Sun ever "made" (they actually rebadged the SPARCle and later the crotchburner 1.2GHz Tadpole Viper, which is the one I have). Since its last refresh the IDPROM had died, as they do when they run out of battery, resetting the MAC address to zeroes and erasing the license for the 802.11b which I never used anyway. But, after fixing the clock to prevent GNOME from puking on the abnormal date, it booted and I figured I'd update Firefox since it still had 38.4 on it. Ginn Chen, first at Sun and later at Oracle, regularly issued builds of Firefox which ran very nicely on SPARC Solaris 10. Near as I can determine, Oracle has never offered a build of any Firefox post-Rust even to the paying customers they're bleeding dry, but I figured I should be able to find the last ESR of 52 and install that. (Amusingly this relic can run a Firefox in some respects more current than TenFourFox, which is an evolved and patched Firefox 45.)
  • Protecting the world’s oceans with open data science
    For environmental scientists, researching a single ecosystem or organism can be a daunting task. The amount of data and literature to comb through (or create) is often overwhelming. So how, then, can environmental scientists approach studying the health of the world’s oceans? What ocean health means is a big question in itself—oceans span millions of square miles, are home to countless species, and border hundreds of countries and territories, each of which has its own unique marine policies and practices. But no matter how daunting this task may seem, it’s a necessary and vital one. So in 2012, the National Center for Ecological Analysis and Synthesis (NCEAS) and Conservation International publicly launched the Ocean Health Index (OHI), an ambitious initiative to measure the benefits that oceans provide to people, including clean water, coastal protections, and biodiversity. The idea was to create an annual assessment to document major oceanic changes and trends, and in turn, use those findings to craft better marine policy around the world.

Openwashing Leftovers

The Last Independent Mobile OS

The year was 2010 and the future of mobile computing was looking bright. The iPhone was barely three years old, Google’s Android had yet to swallow the smartphone market whole, and half a dozen alternative mobile operating systems—many of which were devoutly open source—were preparing for launch. Eight years on, you probably haven’t even heard of most of these alternative mobile operating systems, much less use them. Today, Android and iOS dominate the global smartphone market and account for 99.9 percent of mobile operating systems. Even Microsoft and Blackberry, longtime players in the mobile space with massive revenue streams, have all but left the space. Then there’s Jolla, the small Finnish tech company behind Sailfish OS, which it bills as the “last independent alternative mobile operating system.” Jolla has had to walk itself back from the edge of destruction several times over the course of its seven year existence, and each time it has emerged battered, but more determined than ever to carve out a spot in the world for a truly independent, open source mobile operating system. After years of failed product launches, lackluster user growth, and supply chain fiascoes, it’s only been in the last few months that things finally seem to be turning to Jolla’s favor. Over the past two years the company has rode the wave of anti-Google sentiment outside the US and inked deals with large foreign companies that want to turn Sailfish into a household name. Despite the recent success, Jolla is far from being a major player in the mobile market. And yet it also still exists, which is more than can be said of every other would-be alternative mobile OS company. Read more