Linus Torvalds tagged and pushed out the sixth release candidate (RC6) for the upcoming Linux Kernel version 6.18 on November 16, 2025. This latest release candidate arrived noticeably larger than usual.
In the Linux 6.18-rc6 announcement mail, Linus explained the reason behind the size increase. The size jump happened because of random fluctuation and the timing of various pull requests.
He noted that a large number of varied fixes happened to arrive during this specific week. This made the resulting patch file grow.
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No Need to Worry About Stability
The larger size does not suggest serious underlying problems. Linus Torvalds noted that the changes themselves are mostly small. He observed that the patch consists primarily of many "one- and few-liners".
The overall activity level feels normal, just distributed across a bigger set of files. Since 6.18 continues on its usual path, things appear to be on schedule for a stable final release.
Breaking Down the RC6 Contents
The biggest single contributor to the size was not kernel code but selftests, which accounted for over a quarter of the entire rc6 patch. These tests help ensure the kernel maintains its quality.
Furthermore, driver fixes still formed a major chunk of the patch. Drivers comprised about a quarter of the remaining non-selftest changes.
Another significant portion focused on architecture fixes. These architectural updates benefit various systems, including arm64, loongarch, and x86.
The remaining changes involved a mixed bag of random but important items. This variety included work on networking, BPF, core kernel, filesystems, and core VM.
Key Fixes in Kernel 6.18-rc6
Individual system improvements show steady progress in this release candidate:
- Architectures: Developers applied necessary fixes to arm64 module loading. This prevents module loading failure if dynamic SCS patching fails.
- Virtualization (KVM): The KVM virtualization subsystem also saw important updates. LoongArch KVM specifically received updates. These changes set pages with write attributes when dirty tracking is disabled. Moreover, KVM/x86 received fixes that harden the system against imbalanced loading or putting of guest FPU state.
- Filesystems: Important filesystem maintenance also continued. Btrfs fixes corrected the calculation of conventional zone capacity. They also fixed stripe width calculation for zoned filesystems. Meanwhile, NFSD fixes ensured that SEQUENCE replay sends a valid reply.
- Selftests: The VFIO selftests received several improvements, including the addition of iova range query helpers and fixes for map limit tests.
A Note on a Reported Crash
Following the 6.18-rc6 release, one user reported a significant issue. They stated that after upgrading, all their Golang programs began to crash, even the Go compiler itself.
Linus Torvalds replied he was not aware of this issue. He asked the user to continue running a bisect to find the exact cause of the problem.
Try Linux Kernel 6.18 RC6
The slightly larger size of Linux 6.18-rc6 only reflects concentrated activity from pull requests. It suggests stability is still high for this stage of development.
As with every release, Linus Torvalds asks developers and users to continue testing. Linux Kernel 6.18 RC6 can be downloaded from the Kernel.org website or the Linus Torvalds's git tree.
