The Linux Kernel community recently rolled out Linux Kernel 6.17 RC4, moving us closer to the final release. Linus Torvalds, the kernel's lead developer, announced this release on August 31, 2025, after catching up from his August travels.
Linux 6.17-rc4 release, while routine in its bug fixes, also highlights a significant shift for one filesystem: Bcachefs. Yes, Bcachefs is now officially considered externally maintained, a noteworthy change for the Linux ecosystem.
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Linux 6.17 RC4 is Pretty Normal
In the Linux Kernel 6.17-rc4 announcement mail, Linus expressed relief, stating that the week leading up to RC4 "felt pretty normal".
The statistics, covering both commit numbers and the overall changes, supported this calm sentiment. Indeed, Linus saw "nothing strange" popping out from the updates, suggesting a smooth integration period.
He looks forward to releasing Linux 6.17 "in a timely manner and in good shape," hinting at a robust final product. This calm atmosphere really reflects a generally smooth development cycle for the core kernel.
What's New in Linux 6.17 RC4: Key Updates and Fixes
While mostly routine, this RC4 release did bring some more substantial changes.
Developers pushed a notable driver fix series for the Intel idpf network driver. Furthermore, important updates for arm64 KVM system register handling also made those areas a bit larger.
Beyond these, the release packed a variety of smaller, yet important, adjustments. For example, the drm/amdgpu driver received several fixes, including updates for handling invalid doorbell errors.
HID (Human Interface Device) drivers saw improvements for various devices like the Legion Go and Logitech G PRO 2.
Also, the xfs filesystem got several updates, such as changes to how it manages zoned blocks and atomic writes. These kinds of fixes touched many parts of the kernel, from KVM and PCI to pinctrl and USB.
Overall, these updates aim to improve stability and expand hardware support.
Bcachefs is Now Externally Maintained
One of the biggest news items surrounding the 6.17 cycle isn't about what is in RC4, but rather a significant decision made about a filesystem.
The Linux Kernel no longer supports Bcachefs within its main kernel tree. Linus Torvalds officially moved Bcachefs to an "Externally maintained" status on August 28, 2025.
This decision came after "many long discussion threads, public and private," where Linus felt uncomfortable being involved.
He explained that Kent Overstreet, the Bcachefs lead developer and maintainer, made it clear that Linus "can't even question any bug-fixes and I should just pull anything and everything". Consequently, Linus concluded that they should "part ways".
While Bcachefs has its supporters who laud its technical merits and stability, with users reporting it as becoming stable in tests and effectively repairing corrupted data, community members like Josef Bacik (Btrfs maintainer) and Theodore Ts'o pointed to Kent Overstreet's communication style and behavior as the primary reason for this change, not the code quality itself.
Sasha Levin further emphasized that a "healthy, functioning development community" is important, and Kent's "personal interactions are undermining the health of the community".
Moving Bcachefs out of mainline Kernel is a significant moment in the kernel's development history. It's a shame Bcachefs is no longer part of the mainline Kernel.
Test Linux Kernel 6.14 RC4
Linux Kernel 6.17 RC4 shows steady progress for core functionalities and system stability.
As usual, Linus Torvalds encourages continued testing to ensure a robust final release. Users can get the latest Linux Kernel 6.17 RC4 from the Kernel.org website or the Linus Torvalds's git tree.
The final Linux Kernel 6.17 version is expected to be released on September 28, 2025.
