Linus Torvalds announces the release and general availability of Linux 6.15. It is the latest stable kernel version with several new features and improvements, better hardware support, and more.
Important new features in Linux 6.15 include Rust support for hrtimer and ARMv7 and a new setcpuid=-boot parameter for x86 processors. This is in addition to supporting sched_ext in counting and reporting internal events. Also new are improvements to Intel and AMD PMUs on x86, support for nested virtualization of VGICv3 on ARM, and emulation support for FEAT_PMUv3 on Apple Silicon.
The same applies to an API for receiving information about the mounting and unmounting of file systems, in addition to support for hardware-encrypted keys in the block layer and 48-bit block addressing in the EROFS file system. A new security hook in the io_uring subsystem, which gives security modules more control over allowed operations, is also worth mentioning.
The FUSE file system can now handle file names longer than 1024 characters. And the perf subsystem analyzes delays based on scheduler information. The BPF subsystem received improved verification of programs with loops. The OverlayFS file system received a new mount option, override_creds, which modifies the access rights used for lower layers.
In addition, Linux 6.15 supports new extensions to the RISC-V architecture, including the BFloat16 floating-point extension, the Zaamo and Zalrsc extensions, and the ZBKB extension. Support has also been added for zoned devices in the XFS file system and zero-copy network reception within the io_uring subsystem.
Network improvements also include a new TCP socket option (TCP_RTO_MAX_MS) to set the maximum time between retransmission attempts on IPv4 and a set of new BPF callbacks to retrieve timestamps from different parts of the network stack.
Updated drivers
Hardware support has been expanded with new and updated drivers, supporting devices such as the Apple Touch Bar, Google Pixel Pro 6 smartphone, MYIR Remi Pi development board, Huawei Matebook E Go embedded controller, Milk-V Jupiter RISC-V board, and HP laptops with CS35L41 HDA audio chips.
Linux 6.15 also modifies the ACPI fan driver to support fans with detailed status monitoring. The ACPI button driver has been updated to subscribe to system event notifications and device events. This is required on some systems to wake from sleep mode.
Another change is that support has been removed for 32-bit (x86) systems with more than eight CPUs and/or more than 4 GB of RAM. The Landlock security module has been given a new auditing mechanism to analyze access denials better.
A new fwctl subsystem has also been added, allowing users to create and execute RPCs within device firmware safely. The kernel also includes a new security feature to protect memory allocations from being modified, although this is disabled by default as it may cause some applications to malfunction.
Linux kernel 6.15 is now available for download from Linus Torvalds’ git tree or from the kernel.org website for those who want to compile it manually on a GNU/Linux distribution. However, waiting until the new version is available through your distribution’s stable software sources is recommended.
Now that Linux kernel 6.15 has been released, the merge window is open for the next major kernel version, Linux 6.16, which is expected in late July or early August 2025. Until then, the first Release Candidate will be available for public testing in two weeks, on June 8.