Post Syndicated from corbet original https://lwn.net/Articles/1017565/

Security Week is one of several outlets reporting
that the funding for the CVE program at MITRE disappears as of
April 16.

Maintained by MITRE Corporation, a not-for-profit organization that
operates federal R&D centers, the CVE program is funded through
multiple channels, including the U.S. government, industry
partnerships, and international organizations.

Earlier this month, in anticipation of the US government funding
cuts, MITRE initiated layoffs that affected more than 400 employees
in its Virginia office. The cuts were ordered after the Trump
administration announced more than $28 million in canceled
contracts for the company.

Post Syndicated from corbet original https://lwn.net/Articles/1016842/

It is common, on NUMA systems, to try to allocate all memory on the local
node, since it will be the fastest. That is not the only possible policy,
though; another is weighted interleaving,
which seeks to distribute allocations across memory controllers to maximize
the bandwidth utilization on each. Configuring such policies can be
challenging, though. At the 2025 Linux Storage, Filesystem,
Memory-Management, and BPF Summit, Joshua Hahn ran a session in the
memory-management track about how that configuration might be automated.

Post Syndicated from corbet original https://lwn.net/Articles/1017514/

Security updates have been issued by AlmaLinux (glibc), Red Hat (kernel and kernel-rt), Slackware (perl), SUSE (haproxy, kernel, and webkit2gtk3), and Ubuntu (cimg, perl, protobuf, and webkit2gtk).

Post Syndicated from corbet original https://lwn.net/Articles/1016724/

Andrew Morton, the lead maintainer for the kernel’s memory-management
subsystem, tends to be quiet during the Linux Storage, Filesystem,
Memory-Management, and BPF Summit, preferring to let the developers work
things out on their own. That changes, though, when he leads the
traditional development-process session in the memory-management track. At
the 2025 gathering, this discussion covered a number of ways in which the
process could be improved, but did not unearth any significant problems.

Post Syndicated from corbet original https://lwn.net/Articles/1017325/

Linus has released 6.15-rc2 for testing.
“Nothing particularly stands out to me, but it’s early in the release
yet, so let’s see how it goes.“

Post Syndicated from corbet original https://lwn.net/Articles/1016722/

Knowing how frequently accessed a page of memory is (its “hotness”) is a
key input to many memory-management heuristics. Jonathan Cameron, in a
memory-management track at the 2025 Linux Storage, Filesystem,
Memory-Management, and BPF Summit, pointed out that the number of sources
of that kind of data is growing over time. He wanted to explore the
questions of what commonality exists between data from those sources, and
whether it makes sense to aggregate them all somehow.

Post Syndicated from corbet original https://lwn.net/Articles/1016718/

Compute
Express Link (CXL) memory is not like the ordinary RAM that one might
install into a computer; it can come and go at any time and is often not
present when the kernel is booting. That complicates the management of
this memory. During the memory-management track of the 2025 Linux Storage,
Filesystem, Memory-Management, and BPF Summit, Gregory Price ran a session
on the challenges posed by CXL and how they might be addressed.

Post Syndicated from corbet original https://lwn.net/Articles/1016525/

The Data Access
MONitor (DAMON) subsystem provides access to detailed memory-management
statistics, along with a set of tools for implementing policies based on
those statistics. An update on DAMON by its primary author, SeongJae Park,
has been a fixture of the Linux Storage, Filesystem, Memory-Management, and
BPF Summit for some years. The 2025 Summit was no exception; Park led two
sessions on recent and future DAMON developments, and how DAMON might
evolve to facilitate a more access-aware memory-management subsystem in the
future.

Post Syndicated from corbet original https://lwn.net/Articles/1016366/

Inside this week’s LWN.net Weekly Edition:

• Front: Debian project leader election; 6.15 Merge window; Lots of LSFMM coverage; Joplin.
• Briefs: Firefox hardening; OpenSSH 10.0; Supply chain security; FreeDOS 1.4; OpenSSL 3.5.0; Rust 1.86.0; Quotes; …
• Announcements: Newsletters, conferences, security updates, patches, and more.

Post Syndicated from corbet original https://lwn.net/Articles/1016519/

Tiered-memory systems feature multiple types of memory with varying
performance characteristics; on such systems, good performance depends on
keeping the most frequently used data in the fastest memory. Identifying
that data and placing it properly is a challenge that has kept developers
busy for years. Bharata Rao, presenting remotely during a
memory-management-track session at the 2025 Linux Storage, Filesystem,
Memory-Management, and BPF Summit, led a discussion on a potential solution he has recently
posted; Raghavendra K T was also named on the
session proposal. It seems likely, based on the discussion, that
developers working in this area will not run out of problems anytime soon.

Post Syndicated from corbet original https://lwn.net/Articles/1016426/

The kernel
samepage merging (KSM) subsystem works by finding pages in memory with
the same contents, then replacing the duplicated copies with a single,
shared copy. KSM can improve memory utilization in a system, but has some
problems as well. In two memory-management-track sessions at the 2025
Linux Storage, Filesystem, Memory-Management, and BPF Summit, Mathieu
Desnoyers and Sourav Panda proposed improvements to KSM to
make it work better for specific use cases.

Post Syndicated from corbet original https://lwn.net/Articles/1016416/

Quite a bit of work has been done in recent years to allow the kernel to
make more use of large folios. That progress has not yet reached the
handling of text (executable code) areas, though. During the
memory-management track of the 2025 Linux Storage, Filesystem,
Memory-Management, and BPF Summit, Ryan Roberts ran a session on how that
situation might be improved. It would be a relatively small and contained
operation, but can give a measurable performance improvement.

Post Syndicated from corbet original https://lwn.net/Articles/1016408/

The kernel makes extensive use of per-CPU data as a way to avoid contention
between processors and improve scalability. Using the same technique in
user space is harder, though, since there is little control over which CPU
a process may be running on at any given time. That hasn’t stopped Mathieu
Desnoyers from trying, though; in the memory-management track of the 2025
Linux Storage, Filesystem, Memory-Management, and BPF Summit, he presented
a proposal for how user-space per-CPU memory could work.

Post Syndicated from corbet original https://lwn.net/Articles/1016774/

Security updates have been issued by AlmaLinux (gimp, libxslt, python3.11, python3.12, and tomcat), Debian (ghostscript and libnet-easytcp-perl), Fedora (openvpn, perl-Data-Entropy, and webkitgtk), Red Hat (python-jinja2), SUSE (giflib, pam, and xen), and Ubuntu (apache2, binutils, expat, fis-gtm, linux-azure, linux-azure-6.8, linux-nvidia-lowlatency, linux-azure, linux-azure-fde, linux-azure-5.15, linux-azure-fde-5.15, linux-azure-fips, linux-gcp-fips, linux-hwe-5.4, linux-nvidia, linux-nvidia-tegra-igx, ruby2.7, ruby3.0, ruby3.2, ruby3.3, and vim).

Post Syndicated from corbet original https://lwn.net/Articles/1016715/

ACM Queue looks at
the security problem in the light of a report on Multics security that
was published in 1974.

We are all struggling with a massive shift that has happened in the
past 10 or 20 years in the software industry. For decades, software
reuse was only a lofty goal. Now it’s very real. Modern
programming environments such as Go, Node, and Rust have made it
trivial to reuse work by others, but our instincts about
responsible behaviors have not yet adapted to this new reality.

The fact that the 1974 Multics review anticipated many of the
problems we face today is evidence that these problems are
fundamental and have no easy answers. We must work to make
continuous improvements to open source software supply chain
security, making attacks more and more difficult and expensive.

Post Syndicated from corbet original https://lwn.net/Articles/1016136/

The kernel’s swap subsystem is complex and highly optimized — though not
always optimized for today’s workloads. In three adjacent sessions during
the memory-management track of the 2025 Linux Storage, Filesystem,
Memory-Management, and BPF Summit, Kairui Song, Nhat Pham, and Usama Arif
all talked about some of the problems that they are trying to solve in the
Linux swap subsystem. In the first two cases, the solutions take the form of
an additional layer of indirection in the kernel’s swap map; the third,
which enables swap-in of large folios, may or may not be worthwhile in the
end.

Post Syndicated from corbet original https://lwn.net/Articles/1016119/

Linus Torvalds released 6.15-rc1 and
closed the 6.15 merge window on April 6. By that time, 12,633
non-merge changesets had found their way into his repository; that is
substantially more than were merged during the entire 6.14
development cycle. Just under 6,000 of those changesets were merged after
the first-half merge-window summary was
written.

Post Syndicated from corbet original https://lwn.net/Articles/1016577/

Linus has released 6.15-rc1 and closed the
merge window for this release. “As expected, this was one of the bigger
merge windows, almost certainly just because we had some pent-up
development due to the previous releases being impacted by the holiday
season. That said, while it’s bigger than normal, it’s not some kind of
record-breaking thing.“. In the end, 12.633 non-merge changesets were
pulled into the mainline during this merge window.

Post Syndicated from corbet original https://lwn.net/Articles/1016133/

A typical cloud-computing host will share some of its memory with each
guest that it runs. The host retains its access to that memory, though,
meaning that it can readily dig through that memory in search of data that
the guest would prefer to keep private. The guest_memfd subsystem removes (most of) the
host’s access to guest memory, making the guest’s data more secure. In the
memory-management track of the 2025 Linux Storage, Filesystem,
Memory-Management, and BPF Summit, David Hildenbrand ran a discussion on
the state and future of this feature.

Post Syndicated from corbet original https://lwn.net/Articles/1016124/

Alistair Popple started his session at the 2025 Linux Storage, Filesystem,
Memory-Management, and BPF Summit by proclaiming that ZONE_DEVICE
is “the ugly stepchild” of the kernel’s memory-management subsystem.
Ugly or not, the ability to manage memory that is attached to a peripheral
device rather than a CPU is increasingly important on current hardware.
Popple hoped to cover some of the challenges with ZONE_DEVICE and
find ways to make the stepchild a bit more attractive, if not bring it into
the family entirely.