Linux Kernel 5.15 Released with New NTFS File System, In-Kernel SMB Server, and More

Linux Kernel 5.15

Linus Torvalds announced today the release and general availability of Linux 5.15 as the next long-term support (LTS) kernel series featuring new functionality and improvements.

After seven Release Candidates and two months of hard work, Linux kernel 5.15 is here and it’s ready for mass adoption as the latest LTS (Long-Term Support) kernel for GNU/Linux distributions. You can download it right now from the website or from here (direct download link since isn’t updated yet).

Highlights of Linux 5.15 include a brand new NTFS file system implementation from Parangon Software that’s fully functional and supports all NTFS versions up to 3.1, realtime preemption locking, an in-kernel SMB3 server called ksmbd, Btrfs now supports fs-verity file integrity assurance and ID-mapped mounts, as well as DAMON (Data Access MONitor) for monitoring the memory access pattern of user-space processes.

This release also brings support for the KFENCE and KCSAN tools to the s390 architecture, scheduling support for asymmetric ARM systems, support for per-VLAN multicast in the networking subsystem, the ability to build AArch64 (ARM64) kernels as Hyper-V clients, support for the Management Component Transport Protocol (MCTP) protocol, and out-of-band data support for the Unix-domain sockets.

Also new in Linux kernel 5.15 is support for year 2038 in the XFS file systems, direct I/O support on uncompressed files in the EROFS file system, the ability to migrate memory pages to persistent memory, a new process_mrelease(2) system call that can be used for immediately reclaiming the memory of an exiting process by a supervisor process, as well as support for the pre-allocated trace mechanism in the IOAM subsystem.

Furthermore, the move_mount() system call now allows to add a mount to an existing sharing group, the LLVM integrated assembler is now supported too when building the kernel with Clang, and it’s now possible to put all the tasks within an entire cgroup into the SCHED_IDLE scheduling class.

Of course, there are numerous new and updated drivers for better hardware support. To name a few, Linux 5.15 adds support for Nintendo Wii consoles, Chrome OS EC and Mediatek MT6360 based chargers, Rockchip DesignWare PCIe controllers, Rockchip serial flash controllers, MediaTek Gigabit Ethernet PHYs, Samsung ATNA33XC20 eDP panels, Realtek RTL8188EU Wireless LAN NICs, and NVIDIA Tegra30 thermal sensors.

On top of that, there’s a new VDUSE driver framework that implements virtual block devices in user space and a new gpio-virtio driver that lets guests to access the GPIO lines of the host system. Security-wise, Linux 5.15 adds a new build option to help prevent data from leaking out of functions, adds IMA-based remote attestation support for device mapper, and a new prctl() operation called PR_SPEC_L1D_FLUSH to flush the L1D (level-1 data) cache.

Best of all, Linux 5.15 is an LTS (Long-Term Support) kernel series, since this is the last stable kernel branch released in 2021. Renowned kernel developer Greg Kroah-Hartman will soon announce the LTS status of Linux kernel 5.15 and for how many years it will be supported. Until then, keep an eye on the stable software repositories of your favorite GNU/Linux distribution for Linux 5.15 LTS.

Update 01/11/21: It’s official, Linux kernel 5.15 LTS will be supported for the next two years, until October 2023.

Update 07/02/23: Linux kernel 5.15 LTS support has been extended for three more years, until October 2026.

Last updated 1 year ago

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