Today, Linus Torvalds announced the release and general availability of Linux kernel 6.15, the latest stable kernel version that introduces several new features, fixes and improvements, better hardware support, and more. Just two months after the Linux kernel 6.14.
“Various random small fixes all over, with drivers as usual accounting for most of it. But we’ve got some bcachefs fixes, some core networking, and some mm fixes in there too,” he notes.
As usual, the new version source code, can be downloaded from kernel.org web site.
Ubuntu users will need to wait a bit longer to benefits from these changes officially. Linux 6.15 won’t arrive as an automatic software update for Ubuntu users — Ubuntu 24.04 LTS users can expect to receive a new kernel, Linux 6.13 in July, backported from Ubuntu 25.04.
For more information of kernel history see the Linux kernel version history:
The 6.15 release includes a number of VFS improvements, such as mount notifications, allow creating idmapped mounts from idmapped mounts, support creating detached mounts from a detached mount, allow mount detached mounts on detached mounts, and support detached mounts in overlayfs. There is also support for latency profiling in perf, io_uring networking support for zero-copy receive, a fwctl subsystem to standarize firmware management, bcachefs improvements such as scrub, and support for broadcast TLB invalidation using AMD’s INVLPGB instruction. As always, there are many other features, new drivers, improvements and fixes.
Linux 6.15 introduces a number of significant but “controversial” changes.
The first is the new fwctl subsystem, a controversial addition that has had something of a bumpy road prior to this mainline inclusion, which comes with initial drivers for CXL devices, mlx5 network adapters, and AMD/Pensando distributed services cards. This new framework allows for defined “Remote Procedure Calls” (RPCs) to firmware, which stands to standardise the way device firmware can be configured, updated and debugged, securely, in user-space.
Sticking with controversial changes to make it in, a new security hook for the io_uring subsystem ships in Linux 6.15, despite seeing heated criticism from Linus Torvalds himself, who questioned its purpose and the complexity it adds. The aim of this hook is noble: to improve security by giving SELinux the ability to apply ‘policy controls’ to different kinds of data that is read by the kernel.
On a less contentious note, Linux 6.15 adds support for zero-copy receive (zcrx) via io_uring (the kernel interface for asynchronous I/O operations), potentially improving performance in network-heavy apps, tasks, and workloads.
Linux 6.15 removes support for 32-bit (x86) systems with more than eight CPUs and/or more than 4GB of RAM, and the Landlock security module received a new auditing mechanism designed to make it easier to understand access denials.
As with every kernel release, ARM and RISC-V hardware support continues to expand in Linux 6.15, with the bulk of support concerning industrial, embedded and edge devices.
