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업데이트: 1시간 20분 지남

The 2022 Python Language Summit (PSF blog)

목, 2022/05/12 - 4:35오전
Over on the Python Software Foundation (PSF) blog, Alex Waygood has a report from this year's Python Language Summit. There are reports from each of the nine sessions, including "Python without the GIL", The 'Faster CPython' project: 3.12 and beyond", "F-Strings in the grammar", lightning talks, and more.

[$] Seeking an API for protection keys supervisor

수, 2022/05/11 - 11:11오후
Memory protection keys are a CPU feature that allows additional access restrictions to be imposed on regions of memory and changed in a fast and efficient way. Support for protection keys in user space has been in the kernel for some time, but kernel-side protection (often called "protection keys supervisor" or PKS) remains unsupported — on x86, at least. At the 2022 Linux Storage, Filesystem, Memory-management and BPF Summit (LSFMM), Ira Weiny provided an update on the state of PKS and led a discussion on what the proper in-kernel API for PKS should be.

The malicious "rustdecimal" crate

수, 2022/05/11 - 10:55오후
The Rust Blog warns developers of a malicious crate named rustdecimal, which was evidently targeted at GitLab users who mistype rust_decimal.

The crate contained identical source code and functionality as the legit rust_decimal crate, except for the Decimal::new function.

When the function was called, it checked whether the GITLAB_CI environment variable was set, and if so it downloaded a binary payload into /tmp/git-updater.bin and executed it. The binary payload supported both Linux and macOS, but not Windows.


Security updates for Wednesday

수, 2022/05/11 - 10:25오후
Security updates have been issued by Debian (mutt), Fedora (blender, freerdp, kernel, kernel-headers, kernel-tools, mingw-freetype, and vim), Oracle (kernel and kernel-container), Red Hat (aspell, bind, bluez, c-ares, cairo and pixman, cockpit, compat-exiv2-026, container-tools:3.0, container-tools:rhel8, cpio, dovecot, exiv2, fapolicyd, fetchmail, flatpak, gfbgraph, gnome-shell, go-toolset:rhel8, grafana, grub2, httpd:2.4, keepalived, kernel, kernel-rt, libpq, libreoffice, libsndfile, libssh, libtiff, lynx, maven:3.5, maven:3.6, mod_auth_mellon, mod_auth_openidc:2.3, openssh, php:7.4, pki-core:10.6, postgresql:10, python-lxml, python27:2.7, python3, python38:3.8 python38-devel:3.8, python39:3.9 python39-devel:3.9, qt5-qtbase, qt5-qtsvg, rust-toolset:rhel8, samba, squid:4, udisks2, virt:rhel virt-devel:rhel, webkit2gtk3, xorg-x11-server xorg-x11-server-Xwayland, and zsh), SUSE (gzip and php-composer), and Ubuntu (busybox, cairo, cron, dnsmasq, libsndfile, and nss).

[$] Page pinning and filesystems

수, 2022/05/11 - 8:13오전
It would have been surprising indeed if the 2022 Linux Storage, Filesystem, Memory-management and BPF Summit (LSFMM) did not include a session working toward solutions to the longstanding problems with get_user_pages(), an internal function that locks user-space pages in memory for access by the kernel. The issue has, after all, come up numerous times over the years. This year's event duly contained a session in the joint filesystem and memory-management track, led by John Hubbard, with a focus on page pinning and how it interacts with filesystems.

[$] Recent RCU changes

수, 2022/05/11 - 5:39오전
In a combined filesystem and memory-management session at the 2022 Linux Storage, Filesystem, Memory-management and BPF Summit (LSFMM), Paul McKenney gave an update on the changes to the read-copy-update (RCU) subsystem that had been made over the last several years. He started with a quick overview of what RCU is and why it exists at all. He did not go into any real depth, though, since many of the topics could take a 90-minute session of their own, he said, but he did provide some descriptions of the work that has gone into RCU recently.

[$] The state of memory-management development

수, 2022/05/11 - 1:44오전
The 2022 Linux Storage, Filesystem, Memory-management and BPF Summit (LSFMM) was the first chance for Linux memory-management developers to gather in three years. In a session at the end of the first day led by maintainer Andrew Morton, those developers discussed the memory-management development process. While the overall governance will remain the same, there are nonetheless some significant changes in store for this subsystem.

Fedora 36 released

화, 2022/05/10 - 11:31오후
The Fedora 36 release is now available. Improvements include GNOME 42, Wayland support by default on systems with NVIDIA graphics, Podman 4.0, Ansible 5, the removal of support for legacy ifcfg configuration files, GCC 12, and more; see the release notes for details.

[$] Improving memory-management documentation

화, 2022/05/10 - 10:01오후
Like much of the kernel, the memory-management subsystem is under-documented, and much of the documentation that does exist is less than fully current. At the 2022 Linux Storage, Filesystem, Memory-management and BPF Summit (LSFMM), Mike Rapoport ran a session on memory-management documentation and what can be done to improve it. The result was a reinvigorated interest in documentation, but only time will tell what actual improvements will come from that interest.

Security updates for Tuesday

화, 2022/05/10 - 9:33오후
Security updates have been issued by Debian (kicad and qemu), Fedora (thunderbird), Oracle (expat), Red Hat (samba), Slackware (kernel), and SUSE (firefox, ldb, and rsyslog).

Poettering: Fitting Everything Together

화, 2022/05/10 - 6:44오전
Lennart Poettering designs his ideal desktop operating system in great detail:

First and foremost, I think the focus must be on an image-based design rather than a package-based one. For robustness and security it is essential to operate with reproducible, immutable images that describe the OS or large parts of it in full, rather than operating always with fine-grained RPM/dpkg style packages. That's not to say that packages are not relevant (I actually think they matter a lot!), but I think they should be less of a tool for deploying code but more one of building the objects to deploy.


McQueen: Evolving a GNOME strategy for 2022 and beyond

화, 2022/05/10 - 6:34오전
Robert McQueen describes some initiatives being taken by the GNOME Foundation to attract more users and developers to the platform.

There are many different threats to free access to computing and information in today’s world. The GNOME desktop and apps need to give users convenient and reliable access to technology which works similarly to the tools they already use everyday, but keeps them and their data safe from surveillance, censorship, filtering or just being completely cut off from the Internet. We believe that we can seek both philanthropic and grant funding for this work. It will make GNOME a more appealing and comprehensive offering for the many people who want to protect their privacy.


[$] Dealing with negative dentries

화, 2022/05/10 - 5:35오전
The problem of negative dentries accumulating in the dentry cache in an unbounded manner, as we looked at back in April, came up at the 2022 Linux Storage, Filesystem, Memory-management and BPF Summit (LSFMM). Negative dentries reflect failed file-name lookups, which are then cached, saving an expensive operation if the file name in question is looked up again. There is no mechanism to proactively prune back those cache entries, however, so the cache keeps growing until memory pressure finally causes the system to forcibly evict some of them, which can make the system unresponsive for a long time or even cause a soft lockup.

[$] Ways to reclaim unused page-table pages

월, 2022/05/09 - 10:38오후
One of the memory-management subsystem's most important jobs is reclaiming unused (or little-used) memory so that it can be put to better use. When it comes to one of the core memory-management data structures — page tables — though, this subsystem often falls down on the job. At the 2022 Linux Storage, Filesystem, Memory-management and BPF Summit (LSFMM), David Hildenbrand led a session on the problems posed by the lack of page-table reclaim and explored options for improving the situation.

Four new stable kernels

월, 2022/05/09 - 10:05오후
Greg Kroah-Hartman has announced the release of the 5.17.6, 5.15.38, 5.10.114, and 5.4.192 stable kernels. As usual, these contain important fixes throughout the tree; users of those series should upgrade.

Security updates for Monday

월, 2022/05/09 - 9:54오후
Security updates have been issued by CentOS (firefox and thunderbird), Debian (ecdsautils and libz-mingw-w64), Fedora (cifs-utils, firefox, galera, git, java-1.8.0-openjdk, java-11-openjdk, java-17-openjdk, java-latest-openjdk, mariadb, maven-shared-utils, mingw-freetype, redis, and seamonkey), Mageia (dcraw, firefox, lighttpd, rsyslog, ruby-nokogiri, and thunderbird), Scientific Linux (thunderbird), SUSE (giflib, kernel, and libwmf), and Ubuntu (dbus and rsyslog).

Kernel prepatch 5.18-rc6

월, 2022/05/09 - 9:10오전
The 5.18-rc6 kernel prepatch is out for testing. "Please do go test it all out - because things may look good now, but continued testing is the only thing that will make sure."

GCC 12.1 Released

토, 2022/05/07 - 1:52오전
The GCC project has made the first release of the GCC 12 series, GCC 12.1. As the announcement notes, this month is the 35th anniversary of the GCC 1.0 release. There are lots of changes and fixes in this release, including: This release deprecates support for the STABS debugging format and introduces support for the CTF debugging format. The C and C++ frontends continue to advance with extending support for features in the upcoming C2X and C++23 standards and the C++ standard library improves support for the experimental C++20 and C++23 parts. The Fortran frontend now fully supports TS 29113 for interoperability with C.

[...] On the security side GCC can now initialize stack variables implicitly using -ftrivial-auto-var-init to help tracking down and mitigating uninitialized stack variable flaws. The C and C++ frontends now support __builtin_dynamic_object_size compatible with the clang extension. The x86 backend gained mitigations against straight line speculation with -mharden-sls. The experimental Static Analyzer gained uninitialized variable use detection and many other improvements.


[$] The ongoing search for mmap_lock scalability

금, 2022/05/06 - 11:59오후
There are certain themes that recur regularly at the Linux Storage, Filesystem, Memory-Management, and BPF Summit; among the most reliable is the scalability problems posed by the mmap_lock (formerly mmap_sem) lock. This topic has come up in (at least) 2013, 2018 (twice), and 2019. The 2022 event was no exception, with three consecutive sessions led by Liam Howlett, Michel Lespinasse, and Suren Baghdasaryan dedicated to the topic. There improvements on the horizon, but the problem is far from solved.

Security updates for Friday

금, 2022/05/06 - 10:34오후
Security updates have been issued by Debian (dpdk, mruby, openjdk-11, and smarty3), Oracle (thunderbird), Red Hat (thunderbird), SUSE (chromium, libvirt, python-Twisted, and tar), and Ubuntu (cron and jbig2dec).