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On a typical Linux system, each running CPU will be diverted between 100 and 1000 times each second by the periodic timer interrupt. That interrupt is the CPU's cue to reconsider which process should be running, catch up with read-copy-update (RCU) callbacks, and generally handle any necessary housekeeping. This periodic "tick" can be reasonably compared to the infamous big kernel lock (BKL): it is convenient to have around, but it also has an effect on performance that makes developers wish to abolish it. The key difference might be that getting rid of the timer tick has taken rather longer than was required to eliminate the BKL. The 3.10 kernel will take an important step in that direction, though, with the addition of the "full NOHZ" mode — but a lot of limitations still apply.

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The Linux Foundation Collaboration Summit (LFCS) seems to be a likely venue for an update on the status of building the kernel with Clang/LLVM. Both in 2011 and 2012, we covered those updates. LFCS 2013 continued the trend as LLVMLinux project lead Behan Webster presented the status and plans for the project at LFCS. The gathering lived up to its name as well, since two problems faced by the project were solved through collaboration at the summit.

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Since the advent of object-oriented programming languages around the time of Smalltalk in the 1970s, inheritance has been a mainstay of the object-oriented vision. It is therefore a little surprising that both "Go" and "Rust" — two relatively new languages which support object-oriented programming — manage to avoid mentioning it. In this subscriber-only article, Neil Brown looks at how this classic object-oriented concept has evolved in two recent languages.

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As open source becomes more popular and mature, questions of formalizing the governance and corporate structures of projects are becoming of increasing importance, as can been seen by the rising visibility of various FOSS foundations. At the Linux Foundation Collaboration Summit in San Francisco, Tony Sebro shared his insights about the value that fiscal sponsors bring as umbrella organizations for FOSS projects. Sebro is the General Counsel of Software Freedom Conservancy, which is the home of about 30 free and open source projects, including Samba, Git, and BusyBox.

Click below (subscribers only) for the full report by Martin Michlmayr.

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The 2013 Linux Storage, Filesystem, and Memory Management Summit was held April 18 and 19 in San Francisco, California, immediately after the Linux Foundation's Collaboration Summit. The first set of notes from that gathering is now available; at this point, we have most of the plenary sessions and the entire memory management track written up. The rest of our notes from the Summit will be added in the near future.

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Since the demise of core memory, there has been a fundamental dichotomy in data storage technology: memory is either fast and ephemeral, or slow and persistent. The situation is changing, though, and that leads to some interesting challenges for the Linux kernel. How will we adapt to the coming world where nonvolatile memory (NVM) devices are commonplace? Ric Wheeler led a session at the 2013 Linux Foundation Collaboration Summit to discuss this issue.

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Rust, the new programming language being developed by the Mozilla project, has a number of interesting features. One that stands out is the focus on safety. There are clear attempts to increase the range of errors that the compiler can detect and prevent, and thereby reduce the number of errors that end up in production code.

Click below (subscribers only) for an overview of the Rust language by LWN contributor Neil Brown.

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Given Eben Moglen's long association with the Free Software Foundation, his work on drafting the GPLv3, and his role as President and Executive Director of the Software Freedom Law Center, his talk at the 2013 Free Software Legal and Licensing Workshop promised to be thought-provoking. He chose to focus on two topics that he saw as particularly relevant for the free software ecosystem within the next five years: patents and the decline of copyleft licenses.

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The sixth Free Software Legal and Licensing Workshop, which took place on 4-5 April 2013 in Amsterdam, opened with a keynote from Stefano "Zack" Zacchiroli, the Debian Project Leader (DPL) for the last three years. Zack's aim was to provide the assembled lawyers with an overview of the kinds of legal issues that are faced by Debian and other free software projects and provide suggestions about how lawyers can help free software projects.

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On April 4th, 2013, the PostgreSQL project announced a security vulnerability (CVE-2013-1899) and resulting patch for one of the worst security holes in project history. According to the project web page,『this is the first security issue of this magnitude since 2006.』 Subscribers can click below for PostgreSQL core developer Josh Berkus's look at the vulnerability, its impact, and some questions raised by the project's handling of the vulnerability and release.

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Current news

Version 1.1 of the "Go" programming language has been released. The bulk of the work seems to be in performance improvements, but there's a number of new features as well, including a race detector and an expanded library. See the release notes for details.

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CentOS has updated hypervkvpd (C5: denial of service).

Debian has updated xen (multiple vulnerabilities) and mysql (multiple vulnerabilities).

Fedora has updated plexus-archiver (F18; F17: denial of service) and php-sabredav-Sabre_DAV (F18; F17: local file exposure).

Mageia has updated telepathy-idle (certificate validation error) and kdelibs (username and password disclosure).

Mandriva has updated mesa (code execution).

openSUSE has updated strongswan (12.2; 12.1: authentication bypass), xorg-x11-server (information disclosure), java-1_6_0-openjdk (multiple vulnerabilities), and python-httplib2 (SSL certificate verification failure).

Oracle has updated enterprise kernel (OL6; OL5: multiple vulnerabilities).

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The first PostgreSQL 9.3 beta is out for testing. There are plenty of new features in this release, including writable foreign tables, automatically updatable VIEWs, lateral joins, indexed regular expression searches, checksums to detect filesystem-induced data corruption, and more. "In 9.3, PostgreSQL has greatly reduced its requirement for SysV shared memory, changing to mmap(). This allows easier installation and configuration of PostgreSQL, but means that we need our users to rigorously test and ensure that no memory management issues have been introduced by the change."

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Linus has announced the 3.10-rc1 kernel prepatch and the closure of the merge window for this development cycle. All told, nearly 12,000 changesets were pulled into the mainline during the merge window, making it the busiest such ever. See this article (subscribers only) for a summary of changes merged since last week's merge window update.

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The 3.9.2, 3.8.13, 3.4.45, and 3.0.78 stable updates are out with the usual collection of important fixes. Greg says: "NOTE, this is the LAST 3.8.y kernel release, please move to the 3.9.y kernel series at this time. It is end-of-life, dead, gone, buried, and put way behind us never to be spoken of again. Seriously, move on, it's just not worth it anymore."

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Version 4.1.0 of Gawk (the GNU Awk interpreter) is out. There's lots of new features, including high-precision arithmetic, a completely reworked dynamic extension interface, and more.

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Rob Weir has posted an analysis of the logo contest recently held for Apache OpenOffice. The main blog post showcases the leading vote-getters, but the real meat comes in the detailed report, which breaks down the survey by demographics and examines various ways of interpreting what boils down to a set of individual personal preferences. "With an ordinal interpretation we can look at histograms (counts of scores), at the mode (most frequent response), median (the middle value) and the variation ratio (fraction of scores not in the mode). With an interval interpretation we would assign each point on the scale a numeric value, e.g., 1 for Strongly Dislike to 5 for Strongly Like. Then we could take these scores and calculate means and standard deviations." The logo-selection process now moves to revisions by the leading candidates, aiming for the upcoming 4.0 release.

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Lars Wirzenius and Russ Allbery have posted an essay calling for changes in how the Debian release cycle works; it is mostly aimed at reducing the length of freezes to something close to zero. "The fundamental change is to start keeping our "testing" branch as close to releasable as possible, at all times. For individual projects, this corresponds to keeping the master or trunk branch in version control ready to be released. Practitioners of agile development models, for example, do this quite successfully, by applying continuous integration, automatic testing, and by having a development culture that if there's a severe bug in master, fixing that gets highest priority."

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Fedora has updated owncloud (multiple vulnerabilities).

Mageia has updated mesa (code execution).

Oracle has updated hypervkvpd (denial of service).

Red Hat has updated hypervkvpd (denial of service) and openstack-keystone (password disclosure).

Scientific Linux has updated hypervkvpd (denial of service).

Ubuntu has updated gpsd (code execution).

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PacketFence is a free network access control system — the system that decides whether you get to use the local WiFi network, for example. Version 4.0 is now available. "Packet Fence 4.0 introduces a brand new modern, fast and responsive web administrative interface. It also simplifies the definition of authentication sources in one place and allows dynamic computation of roles. The portal profiles can now be entirely managed from the web interface, simplifying their definitions and eliminating possible configuration mistakes."

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