The last new kernel release of 2025 is here, and it's looking likely this will be the new LTS kernel release.
On the last Sunday of November, Linus Torvalds announced Linux 6.18, the kernel that Ari Lemmke named after him in 1991. It's the last kernel release of the year, and that means it is highly likely 6.18 will be the next Long Term Support (LTS) kernel.
As usual, there are lots of new drivers and improved support for multiple kinds of hardware. There are also many changed and refined features, but not many big exciting new ones. The most visible change in 6.18 is that Linus removed the experimental bcachefs file system that was added in kernel 6.7 almost two years ago and relegated to being externally maintained in September. The bcachefs project now has external repositories to install the file system's DKMS modules on Debian, Ubuntu, Fedora, and openSUSE listed on the project homepage, and mentions that it's included in Arch and NixOS. Aside from that, there's been little news for the last couple of months.
Many of the various other file systems that the kernel directly supports have received improvements. XFS volumes can now be checked and repaired while in use – especially handy for vast server storage volumes for which an offline check takes so long that it means taking machines offline for extended periods. The exFAT driver, used on microSD cards and USB keys in many roles, is now 16 times faster at some operations. The Btrfs code is more parallel in places, ext4 has some functional improvements, the FUSE module for non-kernel file systems is now faster, and there are improvements in cache handling. An unexpected detail there is that for volumes shared over NFSv4, the cache can now be completely disabled.
As always, a new kernel release means built-in support for some new hardware. That means that once the new version gets picked up by distributions, some new kit will start working without the need to install drivers – generally more troublesome on Linux than on Windows – or to use vendors' own custom kernels. This time, handheld gadgets from ASUS, Lenovo, and Shenzhen vendor GamePad Digital all get updated support, along with Sony's DualSense controller. Dell and its Alienware gaming line, as well as HP Omen and multiple ASUS ROG motherboards, get better monitoring and other tweaks. There are also improvements in keyboard and trackpad handling.
It's not all about new hardware. A few years ago, The Reg FOSS desk mourned Intel's cancellation of Optane, the company's persistent memory (PMEM) technology. We felt that Optane had vast potential for re-architecting how OSes work. Optane wasn't the only type of non-volatile RAM, just the most mature – others are still being developed. A new kernel feature called dm-pcache can use PMEM as a high-throughput, low-latency cache for traditional rewriteable media such as SSDs and spinning disks.
There are also lots of improvements in support and handling for a wide variety of x86-64 CPUs, although much of it is server or networking-specific and won't be directly visible even to the keenest of enthusiasts.
The Nouveau open source driver for Nvidia GPUs can now use the GSP firmware for Turing and Ampere family GPUs, and manage their power use better. There's a new Rust driver for Arm's in-house Mali GPUs, as used in a lot of Arm SoCs – although the driver is preliminary so far – and also new support for Rockchip's NPU tensor-math accelerator. Also on the Arm side of the tracks, there's improved support for Apple's M2 SoCs, including the Pro, Max, and Ultra models, thanks to the Asahi Linux project (support for M3 and M4 is still work-in-progress upstream, though, as we mentioned recently). There are also improvements to RISC-V and Loongson support.
After two years of work, 6.18 includes a new Rust version of Binder, Android's inter-process communication manager. As OSnews chronicled in detail back in 2006, Binder originated in BeOS, then moved to Palm where it was part of the multimedia-enabled multitasking Palm OS Cobalt. The C implementation of Binder has been part of the mainline kernel for a decade, since version 3.19.
In what might be a sign of the quiet continued spread of FreeBSD, the kernel can now detect and handle that it is running under FreeBSD's built-in bhyve hypervisor. Coincidentally, FreeBSD 15.0 just appeared as well, and in this release bhyve supports over 255 virtual processors [PDF] in a VM. Now Linux can handle that configuration.
For more than half a decade, the kernel has offered a way to access and manage processes using file handles, which are called pidfds – short for Process Identifier File Descriptor. There's even a special virtual file system for them. In 6.18, creator Christian Brauner has extended this so that now it can handle kernel namespaces too.
Another patch adds support for the new AccECN protocol, or as the Internet Engineering Task Force (IETF) explains, Accurate Explicit Congestion Notification. The relatively new eBPF subsystem allows programs to run inside the kernel and modify its behavior, and there is now preliminary support for cryptographically signing eBPF programs.
When we covered the new NTFSplus driver in October, we mentioned folios, a new mechanism for handling disk storage in larger units, which also got a mention back when kernel 6.16 appeared. Kernel 6.18 introduces another higher level of storage management, but this time for RAM, with sheaves. Kernel boffins may appreciate LWN's in-depth examination of slabs, sheaves, and barns, but for those who prefer an executive summary, this Brain Noises blog is an accessible overview.
For an overview of all the changes in this version, there's a giant Kernelnewbies summary, and, as ever, LWN had a two-part deep dive during the merge window in October: part 1 from early October, and part 2 from mid-October.
The new kernel will soon appear in rolling-release distros. As new versions of both Debian and RHEL came out in 2025, we suspect both will give 6.18 a pass, but it might make it into Ubuntu 26.04 "Resolute Raccoon." Canonical has just started putting out monthly snapshots of the next LTS release. ®