The first new kernel release of the year has arrived — yes, Linux 6.13 has gone stable.

Linux kernel 6.13 adds, as ever, a vast array of improvements, from an updated Raspberry Pi graphics driver promising speed gains, to lazy preemption logic, expanded Rust support and new drivers for a host of hardware, peripherals and digital doohickeys.

Plus, as with all new kernel releases there’s ongoing work to support new and upcoming CPUs and GPUs from industry titans Intel and AMD.

Linus Torvalds quietly confirmed the Linux 6.13 release in an email to the Linux Kernel Mailing List (LKML), noting that as “nothing horrible or unexpected happened last week, so I’ve tagged and pushed out the final 6.13 release.”

If you’d like to learn a lick more detail on the sort of changes Linux 6.13 brings, read on!

Linux 6.13 Features & Changes

Linux kernel 6.13 adds lazy preemption support, an effort to simplify the kernel’s preemption logic and configuration options to deliver better results. In time, its addition may see a reduction in scheduler-related calls throughout the rest of the kernel.

Core kernel changes in Linux 6.13 are a reminder that Linux development remains fluid and open to revision

LWN has a detailed article looking at how preemption works in the kernel, and how lazy preempting shakes things up (for the better) – well worth a read if you’re interested in learning more!

Dynamic resizing of shared memory rings in the io_uring subsystem is plumbed in, thanks to the IORING_REGISTER_RING_RESIZE command. This is a big boon since can open with smaller ring sizes (i.e, use less memory) then scale up as I/O demands increase.

Elsewhere, there’s a new PIDFD_GET_INFO ioctl() operation to fetch information about a process represented by a pidfd; and producing more performant kernel builds using AutoFDO (Automatic Feedback-Directed Optimization) and Propeller optimisation.

And Linux kernel 6.13 sees the workqueue maximum concurrency limit raised from 512 to 2048, a 4x increase may help improve stability by reducing slowdowns caused by workqueue limits, and possibly boost workqueue-heavy workload performance.

Although regular desktop users don’t stand to (directly) benefit, this is an important change that will be keenly felt on server setups and in large-scale computing operations.

These core kernel changes in Linux 6.13 are a reminder that Linux remains fluid and adaptive, that its maintainers are not precious or fixed on certain approaches. Technical merit wins out always, even for significant change proposals.

Architectures & Virtualisation

A “merge” that caught a lot of hype during the Linux 6.13 development cycle added support for older iPhone and iPad chips, from the A7 through to the A11, plus the many X editions in-between.

Understandably, some folks in the Linux community are excited, assuming Linux distros will now magically boot on old iPhones/iPads. It’s not that simple. The commits in 6.13 are for “bare-bones … basic bring-up”, i.e., nothing end-user usable – but it’s a start!

The Loongarch architecture picks up realtime preemption and lazy preemption support in Linux 6.13, while the kernel is also ready to handle RISC-V “Smmpm”, “Smnpm”, and “Ssnpm” pointer-masking extensions.

A new virtual CPUfreq driver is included in Linux kernel 6.13. This enables CPU-frequency coordination between host and guest systems. The goal: improve “performance and power of workloads within VMs [by] sending the frequency of vCPUs as a hint to the host.”

Want to run Linux in a protected VM under the ARM Confidential Compute Architecture (CCA) on ARM64? With Linux 6.13 you can, while support for Guarded Control Stack in userspace offers security hardening and easier profiling.

Filesystems

Linux kernel 6.11 added atomic write support for block devices with NVMe and SCSI, while Linux 6.13 expands this to support atomic write support on ext4 and XFS filesystems (ext4 being Ubuntu’s default filesystem, for those unaware).

Microsoft’s Christian Brauner explains (sic): “an atomic write is a write issed with torn-write protection. This means for a power failure or any hardware failure all or none of the data from the write will be stored, never a mix of old and new data.”

A nice buff.

Elsewhere, Btrfs is equipped to perform encoded reads via io_uring, and will wait for subvolume(s) to complete cleaning operations via a new BTRFS_IOC_SUBVOL_SYNC_WAIT ioctl() command; the reiserfs filesystem was removed from the kernel entirely.

Devices, Drivers, Detritus

Linux 6.13 brings an improved Broadcom V3D kernel driver, used by the Raspberry Pi. Support for 1MB ‘super pages’ and 64KB ‘big pages’ should deliver much faster graphics performance for games and applications with high memory usage.

Over on Intel, newer Alienware X-Series, M-Series, and Dell laptops benefit from reverse-engineered Dell’s WMAX thermal interface support.

The Alienware Command Center app on Windows uses the interface to allow thermal profiles to be configured by users. As that app is not available on Linux and Dell is (yet) to share any documentation about the interface, kernel contributors stepped in.

Linux 6.13 also adds plenty of new drivers for peripherals, devices, and other accessories.

Among them, the $80 Corsair Void headset which can report battery status, microphone location, firmware version, USB wireless status, and sidetone setting; and the new USB-C version of Apple’s Magic Trackpad 2.

A new HID driver is introduced to support budget gaming devices made by Kysona. Presently, it only support for battery reporting for the Kysona M600 gaming mouse (which gets good reviews) but expect more devices to be added in time.

Although the SDUC (SD Ultra Capacity) memory card spec was thrashed out in 2018 to support storage capacities over 2TB (up to a maximum of 128TB), the first cards will go on sale this year. Ahead of then, Linux 6.13 plumbs in support for SDUC cards.

Sticking with storage, Ultra High Speed II (UHS-II) SDXC cards pick up improved performance in Linux 6.13 and the kernel adds support for the NVMe 2.1 specification (amongst a host of other NVMe buffs).

As well as the items mentioned above, other changes in Linux kernel 6.13:

  • Faster CRC32C & AEGIS-128 crypto performance on Intel/AMD
  • Lightweight guard page feature 
  • Nouveau kernel driver DRM Panic support for NVIDIA NV50+ GPUs
  • Ability to disable Radeon 7000 GPUs’ Zero RPM feature
  • Rust trace events, in-place module & memory allocator support
  • Runtime re-partitioning support enabled for select GPUs
  • AMD EPYC 9005 processors now use AMD P-State
  • Allwinner a100 SoC CPUFreq support
  • Support for Kobo Clara 2E eBook reader
  • Big TCP GSO support for WireGuard
  • SELinux now manages policies for individual netlink operations
  • Case-insensitive support for tmpfs
  • Assorted new (undocumented) BPF features
  • File descriptor memory safety
  • New TX H/W traffic shaping API
  • Rust in-place module support
  • Multi-grained timestamps

Plus more — I only pick out the things that sound interesting to me, make my news-senses tingle, or feel are relevant to users of desktop Linux distributions.

See the LWN merge reports (part 1 & part 2) compiled during Linux 6.13 development cycle for comprehensive details.

Getting Linux Kernel 6.13

Wondering how to install the Linux 6.13 kernel in Ubuntu? If you’re a champ at compiling code, do it yourself: source code is available to download.

Otherwise, you’ll need to wait for someone else to package the kernel update for you.

Ubuntu LTS users do receive major new kernel releases back-ported from newer Ubuntu releases, i.e., Ubuntu 24.04 receives kernels from Ubuntu 24.10, 25.04, 25.10, etc as part of Ubuntu’s hardware enablement (HWE) stack.

But Linux kernel 6.13 won’t be part of the HWE since Ubuntu 25.04 isn’t out yet, and will ship with Linux kernel 6.14 (which is only just about to enter development).

Another option are Canonical mainline kernel builds. These aren’t signed, can fail to boot on some hardware, don’t receive security updates, may lack Ubuntu-specific patches/fixes, etc – but some users run them happily.

If there is an important new feature or particular fix you need Linux 6.13 for, keep an eye on that server for pre-packaged DEBs — just know that you use ’em at your own risk, okay!