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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: 49 min 43 sec ago

More stable kernels

Saturday 12th of October 2019 11:19:26 PM
The 5.3.6, 4.19.79, and 4.14.149 stable kernel updates have been released; each contains another set of important updates.

[$] Calibrating your fear of big bad optimizing compilers

Friday 11th of October 2019 02:14:14 PM
As noted earlier, when compiling Linux-kernel code that does a plain C-language load or store, as in "a=b", the C standard grants the compiler the right to assume that the affected variables are neither accessed nor modified by any other thread at the time of that load or store. The compiler is therefore permitted to carry out a surprisingly large number of optimizations, any number of which might ruin your concurrent code's day. Given that current compilers usually do not emit diagnostics warning of potential ruined days, it would be good to have other tools take on this task.

Security updates for Friday

Friday 11th of October 2019 02:04:07 PM
Security updates have been issued by Debian (lucene-solr and ruby-openid), Fedora (krb5 and SDL2), openSUSE (kernel and libopenmpt), and Ubuntu (python2.7, python3.4).

Understanding Scheduling Behavior with SchedViz (Google Open Source Blog)

Thursday 10th of October 2019 10:38:28 PM
The Google Open Source Blog has an announcement of the release of the SchedViz tool that is used internally at the company "to discover many opportunities for better scheduling choices and to root-cause many latency issues". SchedViz provides a GUI to explore kernel traces: "The SchedViz UI displays collections in several ways. A zoomable and pannable heatmap shows system cores on the y-axis, and the trace duration on the x-axis. Each core in the system has a swim-lane, and each swim-lane shows CPU utilization (when that CPU is being kept busy) and wait-queue depth (how many threads are waiting to run on that CPU.) The UI also includes a thread list that displays which threads were active in the heatmap, along with how long they ran, waited to run, and blocked on some event, and how many times they woke up or migrated between cores. Individual threads can be selected to show their behavior over time, or expanded to see their details."

[$] BPF at Facebook (and beyond)

Thursday 10th of October 2019 04:47:38 PM
It is no secret that much of the work on the in-kernel BPF virtual machine and associated user-space support code is being done at Facebook. But less is known about how Facebook is actually using BPF. At Kernel Recipes 2019, BPF developer Alexei Starovoitov described a bit of that work, though even he admitted that he didn't know what most of the BPF programs running there were doing. He also summarized recent developments with BPF and some near-future work.

Security updates for Thursday

Thursday 10th of October 2019 01:47:25 PM
Security updates have been issued by Debian (clamav, libtomcrypt, and rsyslog), Fedora (suricata), SUSE (libopenmpt and python-requests), and Ubuntu (libsoup2.4 and octavia).

[$] LWN.net Weekly Edition for October 10, 2019

Thursday 10th of October 2019 12:58:31 AM
The LWN.net Weekly Edition for October 10, 2019 is available.

[$] An update on the input stack

Wednesday 9th of October 2019 09:59:52 PM
The input stack for Linux is an essential part of interacting with our systems, but it is also an area that is lacking in terms of developers. There has been progress over the last few years, however; Peter Hutterer from Red Hat came to the 2019 X.Org Developers Conference to talk about some of the work that has been done. He gave a status report on the input stack that covered development work that is going on now as well as things that have been completed in the last two years or so. Overall, things are looking pretty good for input on Linux, though the "bus factor" for the stack is alarmingly low.

Stallman: No radical changes in GNU Project

Wednesday 9th of October 2019 06:46:01 PM
Richard Stallman has issued a brief statement saying that there will not be any radical changes in the GNU Project's goals, principles and policies. "I would like to make incremental changes in how some decisions are made, because I won't be here forever and we need to ready others to make GNU Project decisions when I can no longer do so. But these won't lead to unbounded or radical changes."

[$] Free software support for virtual and augmented reality

Wednesday 9th of October 2019 04:05:12 PM
A talk at the recent X.Org Developers Conference in Montréal, Canada looked at support for "XR" in free software. XR is an umbrella term that includes both virtual reality (VR) and augmented reality (AR). In the talk, Joey Ferwerda and Christoph Haag from Collabora gave an overview of XR and the Monado project that provides support for those types of applications.

Security updates for Wednesday

Wednesday 9th of October 2019 02:57:03 PM
Security updates have been issued by Fedora (chromium), openSUSE (rust and sqlite3), SUSE (dnsmasq, firefox, and kubernetes, patchinfo), and Ubuntu (python2.7, python3.5, python3.6, python3.7).

OpenSSH 8.1 released

Wednesday 9th of October 2019 02:39:40 PM
OpenSSH 8.1 is out. It includes some security fixes, including the encryption of keys at rest to defend them against speculative-execution attacks. There is also an experimental new signature and verification mechanism for public keys.

Six stable kernels

Tuesday 8th of October 2019 03:14:03 PM
Stable kernels 5.3.5, 5.2.20, 4.19.78, 4.14.148, 4.9.196, and 4.4.196 have been released. They all contain the usual set of important fixes. This is the last 5.2 kernel and users should move to the 5.3.y kernel series now.

Security updates for Tuesday

Tuesday 8th of October 2019 03:01:30 PM
Security updates have been issued by Debian (openjpeg2, openssh, and xen), openSUSE (dovecot23, jasper, libseccomp, lxc, putty, and singularity), Red Hat (bind, kernel, polkit, python, and wget), and Ubuntu (unbound).

[$] Adding the pidfd abstraction to the kernel

Monday 7th of October 2019 03:59:40 PM
One of the many changes in the 5.4 kernel is the completion (insofar as anything in the kernel is truly complete) of the pidfd API. Getting that work done has been "a wild ride so far", according to its author Christian Brauner during a session at the 2019 Kernel Recipes conference. He went on to describe the history of this work and some lessons for others interested in adding major new APIs to the Linux kernel.

Richard Stallman and the GNU project

Monday 7th of October 2019 03:59:24 PM
While Richard Stallman has resigned from the Free Software Foundation and MIT, he continues to hold onto his position as the head of the GNU project. Now, the FSF has announced that it is "working with GNU leadership on a shared understanding of the relationship for the future" and is seeking comments from the community on what that should be.

Meanwhile, a group of maintainers for specific GNU projects has posted a joint statement calling for new leadership at GNU. "We believe that Richard Stallman cannot represent all of GNU. We think it is now time for GNU maintainers to collectively decide about the organization of the project. The GNU Project we want to build is one that everyone can trust to defend their freedom."

Security updates for Monday

Monday 7th of October 2019 02:24:19 PM
Security updates have been issued by Debian (jackson-databind, libapreq2, libreoffice, novnc, phpbb3, and ruby-mini-magick), Fedora (mbedtls and mosquitto), Mageia (xpdf), openSUSE (bind, firefox, nginx, openssl-1_0_0, php7, python-numpy, and thunderbird), Oracle (kernel), SUSE (ansible1, ardana-ansible, ardana-cluster, ardana-db, ardana-extensions-nsx, ardana-glance, ardana-input-model, ardana-installer-ui, ardana-manila, ardana-monasca, ardana-neutron, ardana-nova, ardana-octavia, ardana-opsconsole-ui, ardana-osconfig, ardana-service, ardana-tls, crowbar-core, crowbar-ha, crowbar-openstack, crowbar-ui, grafana, novnc, openstack-cinder, openstack-dashboard, openstack-designate, openstack-glance, openstack-heat, openstack-horizon-plugin-heat-ui, openstack-horizon-plugin-monasca-ui, openstack-ironic, openstack-ironic-python-agent, openstack-keystone, openstack-manila, openstack-neutron, openstack-neutron-gbp, openstack-nova, openstack-octavia, openstack-sahara, openstack-tempest, openstack-watcher, python-ardana-configurationprocessor, python-cinder-tempest-plugin, python-urllib3, rubygem-easy_diff, bind, compat-openssl098, nginx, and openssl-1_0_0), and Ubuntu (linux-kvm, linux-raspi2, linux-snapdragon and openexr).

Kernel prepatch 5.4-rc2

Sunday 6th of October 2019 09:59:59 PM
The second 5.4 kernel prepatch is out for testing. "So nothing looks particularly worrisome, but usually rc2 is fairly calm and it takes a while for any regressions to be noticed." This release also changes the code name to "Nesting Opossum".

Some weekend stable kernel updates

Sunday 6th of October 2019 04:41:59 PM
The 5.3.4, 5.2.19, 4.19.77, 4.14.147, 4.9.195, and 4.4.195 stable kernel updates have all been released; each contains a relatively large set of important fixes and updates.

[$] What to do about CVE numbers

Friday 4th of October 2019 03:14:31 PM
Common Vulnerability and Exposure (CVE) numbers have been used for many years as a way of uniquely identifying software vulnerabilities. It has become increasingly clear in recent years that there are problems with CVE numbers, though, and increasing numbers of vulnerabilities are not being assigned CVE numbers at all. At the 2019 Kernel Recipes event, Greg Kroah-Hartman delivered a "40-minute rant with an unsatisfactory conclusion" on CVE numbers and how the situation might be improved. The conclusion may be "unsatisfactory", but it seems destined to stir up some discussion regardless.

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