Linux Kernel 6.9 Officially Released, This Is What’s New

This release introduces Rust support on AArch64 (ARM64) architectures and support for the Intel FRED (Flexible Return and Event Delivery) mechanism.
Linux Kernel 6.9

Linus Torvalds announced today the release and general availability of Linux kernel 6.9, the latest stable version of the Linux kernel that introduces several new features and improved hardware support.

Highlights of Linux kernel 6.9 include Rust support on AArch64 (ARM64) architectures, support for the Intel FRED (Flexible Return and Event Delivery) mechanism for improved low-level event delivery, support for AMD SNP (Secure Nested Paging) guests, and a new dm-vdo (virtual data optimizer) target in device mapper for inline deduplication, compression, zero-block elimination, and thin provisioning.

Linux kernel 6.9 also supports the Named Address Spaces feature in GCC (GNU Compiler Collection) that allows the compiler to better optimize per-CPU data access, adds initial support for FUSE passthrough to allow the kernel to serve files from a user-space FUSE server directly, adds support for the Energy Model to be updated dynamically at run time, and introduces a new LPA2 mode for ARM 64-bit processors.

Rust language has been updated to version 1.76.0 in Linux 6.9, which also reworks the locking mechanism in the GPIO subsystem, adds support for the ORC stack unwinder and kernel live patching for the LoongArch architecture, mitigates the RFDS (Register File Data Sampling) vulnerability affecting Intel Atom processors, and adds support for the membarrier() system call for the RISC-V architecture.

Other noteworthy changes in Linux kernel 6.9 include LZ4 compression support for the hibernation image creation and loading code, support for NFSD administrators to revoke NFSv4’s open and lock state, subvolume children btree support, improved journal pipelining, discard path improvements, improved directory structure checking, and new mm helper in the bcachefs file system introduced in Linux kernel 6.8.

The F2FS (Flash-Friendly File System) flash file system received zoned block device support, per-file compression, and enhanced data recovery after a sudden power cut on a zoned block device, the exFAT file system received improvements to directory synchronization performance, the EXT4 file system received an inode flag for atomic writes and online resize improvements, and the Btrfs file system received more zoned mode fixes and minor performance optimizations.

On top of that, the memory-management performance has been improved, the perf tool received several new features, BPF token support was added for delegating a subset of BPF subsystem functionality from privileged system-wide daemons like systemd, and ARM 64-bit processors received initial support for the contiguous PTE bit to allow the TLBs to map a range larger than a single PTE if the range is physically contiguous.

Networking enhancements in Linux 6.9 include TCP_NOTSENT_LOWAT support in MPTCP, support for forwarding ICMP Error messages in IPSec, support for the independent control state machine for bonding per IEEE 802.1AX-2008 5.4.15, support for hosts with multiple disjoint MCTP networks, supports new 2.5GE and 5GE Energy Efficient Ethernet (EEE) link modes, SPP (signaling and payload protected) AMSDU support, and wider-bandwidth OFDMA support.

New drivers are included in Linux 6.9 for ChromeOS’s Embedded Controller, Marvell’s Octeon PCI Endpoint NIC VF, RENESAS’s FemtoClock3 Wireless clock generator, Qualcomm’s Snapdragon X Elite (X1E80100) processor, Samsung’s Wireless Action Mouse, Keyboard, GamePad, Book Cover, Universal Keyboard, and HOGP Keyboard Bluetooth devices, Snakebyte’s gamepads, as well as Goodix Berlin’s I2C and SPI touch controllers.

It also adds more AMD IP blocks to support future AMD hardware, updates the Intel Xe graphics driver, adds Displayport tunneling support for the Intel i915 graphics driver, adds HDMI support for the Rockchip RK3128 processor, adds SoundWire support for AMD ACP 6.3 systems and DSPless mode support for Intel Soundwire systems, battery charge control support for Fujitsu laptops, and refresh rate key support for Lenovo IdeaPad laptops.

Last but not least, Linux kernel 6.9 marks the EXT2 file system as being deprecated as it’s not (and it won’t be) patched against the Year 2038 problem. While you can still use EXT2 in Linux kernel 6.9, the Linux kernel developers recommend avoiding it. On the same note, Linux 6.9 finally removes the old NTFS filesystem implementation, defaulting to NTFS3 for supporting NTFS filesystems.

Linux kernel 6.9 will be a short-lived branch supported for only a couple of months. It will be succeeded by Linux kernel 6.10, whose merge window has now been officially opened by Linus Torvalds. Linux kernel 6.10 is expected to be released in mid or late September 2024. Meanwhile, you can download Linux kernel 6.9 right now from Linus Torvalds’ git tree or the kernel.org website.

Last updated 2 weeks ago

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