William Woodruff, better known online as "yossarian", has published a blog post to make the case that users should not place their trust in trusted publishing: Trusted Publishing is a mechanism for establishing trust between an external machine identity (like a CI/CD workflow) and one or more projects on a package index/registry. The "trust" in "Trusted Publishing" refers to that trust relationship, and not to anything else. It is not, and cannot be, a signal for package trust or quality. You cannot use it to determine whether a package is safe or "good," and PyPI consciously stymies attempts to misuse it for that purpose by not rendering it as a "green checkmark" or anything else of the sort. Or as another framing: Trusted Publishing is just a form of authentication. It doesn't tell you anything other than that an upload was authenticated, which all uploads to PyPI are. LWN covered trusted publishing in June.
Puranjay Mohan shared some of the work he's been doing recently on improving the performance of read-copy-update (RCU) at the 2026 Linux Storage, Filesystem, Memory-Management, and BPF Summit; his talk would have been nice context to have earlier in the day when Harry Yoo and Alexei Starovoitov led a session about the new kmalloc_nolock() function that allows for lockless allocation from any kernel context, and which interacts with the RCU subsystem to allow that. This article therefore covers the two sessions together and in the reverse order, to provide that missing context.
OpenSSH 10.4 has been released. In addition to a number of security and bug fixes, there are a few notable changes; this release adds experimental support for a composite post-quantum signature scheme combining ML-DSA 44 and Ed25519 as described in this IETF draft. With 10.4, if OpenSSH is compiled with sandbox support it will fail on Linux systems that have not enabled SECCOMP or NO_NEW_PRIVS; prior to this release, sshd would log an error but continue operation. See the release notes for a full list of changes.
Conversations about the kernel's filesystem implementations often involve a layer called "iomap", but relatively few people can reliably say what iomap actually is. That is just the kind of gap that LWN exists to fill. In short, iomap handles the mapping between data in the filesystem space (identified by a file of interest, and an offset within that file) and in the storage space (which may be a memory location, or a set of blocks on a storage device). Using that mapping, iomap handles a long list of common, filesystem-related tasks, allowing a lot of boilerplate code to be removed from individual filesystem implementations.
The 7.2-rc2 kernel prepatch is out for testing. Linus said: "It's Sunday afternoon, and rc2 is out. Things look very normal - it's not a small rc2, but it's in line with recent releases, and slightly smaller than rc2 was in 7.1. Let's see how that all continues, but so far so good."
Greg Kroah-Hartman has announced the release of the 7.1.3, 6.18.38, 6.12.95, 6.6.144, 6.1.177, 5.15.211, and 5.10.260 stable kernels. Several kernels in this batch include a fix for a vulnerability introduced in the 6.0 kernel in IPv6 (CVE-2026-53362), which could allow an attacker to escape a container and gain root access. There is also a fix for a use-after-free bug in KVM (CVE-2026-53359) that was introduced in the 2.6.36 kernel. As usual, each stable kernel includes a number of fixes throughout the tree. Users are advised to upgrade.
The GNU Guix project has announced three vulnerabilities in the guix substitute utility as well as a fourth that affects the guix pull and guix time-machine commands. The impact of the vulnerabilities ranges from remote-privilege escalation to local disclosure of sensitive files. The remote exploitation of guix substitute only requires that the vulnerable system attempt to download a binary substitute. Any configured substitute server, including ones discovered using guix-daemon's --discover option, can exploit this, and so can a man-in-the-middle (MITM), regardless of whether https is used in the substitute server urls. The local exploitation of guix substitute only requires the ability to connect to guix-daemon's socket, which by default any user can do. Separately, another security issue (CVE ID pending) was identified in guix pull and guix time-machine, which enables anyone who can control the channels file used by these commands to cause a file to be created or overwritten whereve
A number of problems related to negative directory entries (dentries) were the topic of a filesystem-track session at the 2026 Linux Storage, Filesystem, Memory Management, and BPF Summit. Negative dentries are used to indicate that a file of a given name does not exist in a directory; it is an optimization that short-circuits the lookup of the file name when the answer is already known. Miklos Szeredi led a session that discussed some problems that come from having too many negative dentries for a directory.
In August 2025, the CalyxOS privacy-focused Android distribution announced that it was pausing all releases while it reworked its release process, security protocols, and changed its signing keys following the departure of one of its founders. The project has now announced that it is "officially back from the hiatus" with the 7.2.2.0 release. CalyxOS 7.2.2.0 is signed by us using a new HSM-based, open-source signing solution we designed to enhance the security of the entire signing process, ensure redundancy, and remove single points of failure. You can verify CalyxOS 7.2.2.0 and future builds following these instructions. For anyone who is interested, the security audit report of the HSM provisioning ceremony script can be found here. In addition, we also went through significant infrastructure improvements. In particular, we have set up a cleaner server structure to streamline each release. In response to Google's less frequent AOSP source code releases, our team developed scripts to
A few astute observers have noticed that some content on kernel.org had disappeared and were understandably concerned. Konstantin Ryabitsev has provided an update via social.kernel.org: There was an unfortunate error while changing the kernel.org primary/secondary mirroring infrastructure, which resulted in the /pub tree suddenly becoming empty. No data was lost, just public mirror copies. Everything is now being restored, but deletes are fast and restores are slow, so thank you for your patience! The incident is being tracked on the Linux Foundation's IT status page.
We were made aware today of an email sent to a reader that was spoofed to appear to be from LWN. The message claimed, among other things, that we were providing personal information about the reader to another site user. As is explained in our privacy policy we do not, and would not, provide such information. If any other readers have received an odd message from LWN, it is an attempt at a hoax; if in doubt, please check the DKIM header of the email. Any email that does come from LWN will have a proper DKIM signature in its headers. If you receive such a message, please feel free to send it to us, with its headers intact. But to reiterate, we are not providing any user information upon request, nor banning any accounts. We hope this will not be a recurring problem.
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