On April 21, Andrew Morton let it be known that he intends to begin stepping away from the maintainership of kernel's memory-management subsystem — a responsibility he has carried since before memory management was even seen as its own subsystem. At the 2026 Linux Storage, Filesystem, Memory Management, and BPF Summit, one of the first sessions in the memory-management track was devoted to how the maintainership would be managed going forward. There are a lot of questions still to be answered.

The 7.0.4, 6.18.27, and 6.12.86 stable kernels have been released; each contains another set of important fixes.

Inside this week's LWN.net Weekly Edition:

• Front: LLMs and security; restartable sequences and TCMalloc; Fedora and GNOME bug reports; Prolly trees; Arm on s390.
• Briefs: NHS open source; Alpine outage; GCC 16.1; Incus 7.0 LTS; NetHack 5.0.0; PHP license; Quotes; ...
• Announcements: Newsletters, conferences, security updates, patches, and more.

The PHP project has long shipped under its own license — except for the parts under the Zend Engine License. The PHP project has now announced that the PHP license has been retired, and the PHP code has been relicensed under the three-clause BSD license. See this blog entry for more details.

Getting here required more than writing an RFC. The PHP License gives the PHP Group the authority to change it, which meant tracking down each of the original PHP Group members and getting their written consent. Each approved the proposal. Perforce Software, the successor to Zend Technologies, needed to sign off on the Zend Engine side, as well. They provided a formal letter confirming their full authority and support for the change. I hired an attorney to review the proposal and provide advice on any legal questions that might surface during the discussion period. Speaking of which, I allowed for a six-month community discussion period preceding the vote, which passed unanimously.

LWN covered the license-change process back in March.

The second 7.1 kernel prepatch is out for testing. "It's not small, and while it's a bit early to say for sure, I do suspect we're seeing the same continued pattern of more patches than usual - probably due to AI tooling - that we saw in 7.0."

Hyrum's Law states that any observable behavior of a system will eventually be depended upon by somebody. The kernel community is currently contending with a clear demonstration of that principle. The recent work to address some restartable-sequences performance problems in the 6.19 release maintained the documented API in all respects, but that was not enough; Google's TCMalloc library, as it turns out, violates the documented API, prevents other code from using restartable features, and breaks with 6.19. But the kernel's no-regressions rule is forcing developers to find a way to accommodate TCMalloc's behavior.

Inside this week's LWN.net Weekly Edition:

• Front: Famfs; Python packaging council; Zig concurrency; pages and folios; Strawberry music manager; 7.1 merge window.
• Briefs: GnuPG 2.5.19; Copy Fail; Plasma security; Fedora 44; Ubuntu 26.04; Niri 26.04; pip 26.1; RIP Seth Nickell; RIP Tomáš Kalibera; Quotes; ...
• Announcements: Newsletters, conferences, security updates, patches, and more.

By the time Linus Torvalds released 7.1-rc1 and closed the 7.1 merge window, 12,996 non-merge changesets had been pulled into the mainline repository; just over 9,000 of those arrived after the first-half summary was written. These changes were more driver-oriented than those seen earlier, but still also included many new features across the kernel as a whole.

Linus has released 7.1-rc1 and closed the merge window for this release.

Things look fairly normal, although we do have a few different projects to cull some old hardware support to help minimize maintenance burden: phasing out i486 support (configs deleted, code deletions to follow) and independently starting to remove some really old networking hardware support, and removing some SoC support that never went anywhere.

But we're more than making up for any stale code removal with all the new features and code added, so the diffstat still shows many more lines added than removed.

The kernel coverage here at LWN often touches on memory-management topics and, as a result, tends to talk a lot about both pages and folios. As the folio transition in the kernel has moved forward, it has often become difficult to decide which term to use in writing that is meant to be both approachable and technically correct. As this work continues, it will be increasingly common to use "folio" rather than page. This article is intended to be a convenient reference for readers wanting to differentiate the two terms or understand the state of this transition.

The famfs filesystem first showed up on the mailing lists in early 2024; since then, it has been the topic of regular discussions at the Linux Storage, Filesystem, Memory Management and BPF (LSFMM+BPF) Summit. It has also, as result of those discussions, been through some significant changes since that initial posting. So it is not surprising that a suggestion that it needed to be rewritten yet again was not entirely well received. How much more rewriting will actually be needed is unclear, but more discussion appears certain.

The 7.0.1, 6.19.14, 6.18.24, and 6.12.83 stable kernels have been released; each contains another set of important fixes. Note that the 6.19.x line ends with 6.19.14.

There are a number of ongoing efforts to remove kernel code, mostly from the networking subsystem, as an alternative to dealing with the increase in security-bug reports from large language models. The proposed removals include ISA and PCMCIA Ethernet drivers, a pair of PCI drivers, the ax25 and amateur radio subsystem, the ATM protocols and drivers, and the ISDN subsystem.

Remove the amateur radio (AX.25, NET/ROM, ROSE) protocol implementation and all associated hamradio device drivers from the kernel tree. This set of protocols has long been a huge bug/syzbot magnet, and since nobody stepped up to help us deal with the influx of the AI-generated bug reports we need to move it out of tree to protect our sanity.

This Firefox blog post reports that the Firefox 150 release includes fixes for 271 vulnerabilities found by the Claude Mythos preview.

Elite security researchers find bugs that fuzzers can't largely by reasoning through the source code. This is effective, but time-consuming and bottlenecked on scarce human expertise. Computers were completely incapable of doing this a few months ago, and now they excel at it. We have many years of experience picking apart the work of the world's best security researchers, and Mythos Preview is every bit as capable. So far we've found no category or complexity of vulnerability that humans can find that this model can't.

This can feel terrifying in the immediate term, but it's ultimately great news for defenders. A gap between machine-discoverable and human-discoverable bugs favors the attacker, who can concentrate many months of costly human effort to find a single bug. Closing this gap erodes the attacker's long-term advantage by making all discoveries cheap.

One of the more significant changes in the 7.0 kernel release is to use the lazy-preemption mode by default in the CPU scheduler. The scheduler developers have wanted to reduce the number of preemption modes for years, and lazy preemption looks like a step toward that goal. But then there came this report from Salvatore Dipietro that lazy preemption caused a 50% performance regression on a PostgreSQL benchmark. Investigation showed that the situation is not actually so grave, but the episode highlights just how sensitive some workloads can be to configuration changes; there may be surprises in store for other users as well.

The 7.1 merge window opened on April 12 with the release of the 7.0 kernel. Since then, 3,855 non-merge changesets have been pulled into the mainline repository for the next release. This merge window is thus just getting started, but there has still been a fair amount of interesting work moving into the mainline.

Inside this week's LWN.net Weekly Edition:

• Front: LLM security reports; OpenWrt One build system; Vim forks; removing read-only THPs; 7.0 statistics; MusicBrainz Picard.
• Briefs: OpenSSL 4.0.0; Relicensing; Servo; Zig 0.16.0; Quotes; ...
• Announcements: Newsletters, conferences, security updates, patches, and more.

Version 4.0.0 of the OpenSSL cryptographic library has been released. This release includes support for a number of new cryptographic algorithms and has a number of incompatible changes as well; see the announcement for the details.

Linus Torvalds released the 7.0 kernel as expected on April 12, ending a relatively busy development cycle. The 7.0 release brings a large number of interesting changes; see the LWN merge-window summaries (part 1, part 2) for all the details. Here, instead, comes our traditional look at where those changes came from and who supported that work.

Linus has released the 7.0 kernel after a busy nine-week development cycle.

The last week of the release continued the same "lots of small fixes" trend, but it all really does seem pretty benign, so I've tagged the final 7.0 and pushed it out.

I suspect it's a lot of AI tool use that will keep finding corner cases for us for a while, so this may be the "new normal" at least for a while. Only time will tell.

Significant changes in this release include the removal of the "experimental" status for Rust code, a new filtering mechanism for io_uring operations, a switch to lazy preemption by default in the CPU scheduler, support for time-slice extension, the nullfs filesystem, self-healing support for the XFS filesystem, a number of improvements to the swap subsystem (described in this article and this one), general support for AccECN congestion notification, and more. See the LWN merge-window summaries (part 1, part 2) and the KernelNewbies 7.0 page for more details.