Linux Kernel 6.18 RC3 Released With SMB, XFS And Btrfs Fixes

Linus Torvalds announced the release of third release candidate (RC3) for the upcoming Linux Kernel version 6.18. He tagged and released this version on 26 October 2025.

Linux 6.18-rc3 is "Fairly Normal"

In the Linux 6.18-rc3 announcement mail, Linus Torvalds reported that things feel "fairly normal" this week. In fact, he noticed the numbers show a slightly calmer period than usual.

However, this calm behavior probably just reflects the normal changes in when developers send their pull requests. The list of changes, i.e. the diffstat, looks both short and flat.

Specifically, the high-level statistics look exactly like they should. Developers included many patches in this release candidate. About half of those patches are for drivers.

This driver count includes the devicetree bindings that link hardware to the kernel. Furthermore, the remaining changes are pretty random and spread out across the entire kernel.

Remember that this calm release follows a busier week. The previous version, Linux 6.18-rc2, was actually "on the bigger side".

That larger size helped address several regressions developers found and reported after the first RC1 release. Therefore, the current RC3 version suggests the development cycle is settling down nicely.

A Few Key Fixes are Included in RC3

The kernel development team focuses heavily on fixes in these release stages. Most importantly, the biggest changes in this release candidate tackle smbdirect fixes. These fixes cover issues on both the client side and the server side of the SMB protocol.

After the SMB fixes, the next notable area of updates includes several XFS fixes:

• XFS: Updates include avoiding busy loops in GCD and caching the open zone in inode->i_private. Fixes were also made to ensure -EFAULT is not used in xfs_init_fs_context and to prevent setting bt_nr_sectors to a negative number. Warnings were added for deprecated mount options, and errors were made louder for defunct mount options

The other filesystems (Btrfs and Erofs) also saw some minor updates.

• Btrfs: A fix addresses a delayed_node ref_tracker use after free issue.
• Erofs: Fixes were introduced to handle crafted invalid cases for encoded extents and to avoid infinite loops caused by corrupted subpage compact indexes.

The rest of the changes are simply random noise and minor updates. Examples of other subsystem updates include:

• IO_URING: Updates to switch SQ poll away from getrusage() for CPU accounting, improve logic on when to update stime usage, and fix buffer auto-commit for multishot uring_cmd.
• ARM64/MIPS/RISC-V: Architecture-specific updates include memory tagging extensions (MTE) handling on arm64, fixing vDSO data for late-initialized keys on RISC-V, and fixing PCI southbridge legacy resource reservations on MIPS Malta.
• PCI: ASPM was updated to enable only L0s and L1 for devicetree platforms.
• Rust: Several updates related to the Rust infrastructure, including cleaning up warnings and fixing formatting in rust_binder and rust/bitmap.

Test Linux Kernel 6.18 RC3

Please keep testing the new RC3 version as development continues! You can download the Kernel 6.18 RC3 from the Kernel.org website or the Linus Torvalds's git tree.