The x32 subarchitecture may be removed

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.

Source: LWN

[$] DMA and get_user_pages()

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.

Source: LWN

Security updates for Wednesday

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).

Source: LWN

Git 2.20.0 released

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.

Source: LWN

Firefox 64 released

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.

Source: LWN

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

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.

Source: LWN

Security updates for Tuesday

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).

Source: LWN

[$] Measuring container security

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.

Source: LWN