Linus Torvalds has released the sixth release candidate for Linux Kernel 6.17, marking a remarkably calm development cycle with minimal reported issues. The release features a diverse distribution of changes across various subsystems, including filesystem fixes (approximately one-third), driver fixes (about one-third), and core networking, CPU speculation mitigations, documentation updates, self-test enhancements, and minor adjustments (the final third). These updates address issues in file systems such as Btrfs, Ceph, EROFS, and NFS, as well as drivers like AMDGPU, XE, Nouveau, Mediatek DRM, and Panthor. The release is on track for a normal release in two weeks, with continued emphasis on user testing to avoid complacency.

Linus Torvalds Releases Sixth Linux Kernel 6.17 Release Candidate

Linus Torvalds has released the sixth release candidate for Linux Kernel 6.17, marking a remarkably calm development cycle with minimal reported issues. He attributes this to August vacations, indicating that the release is on track for a normal release in two weeks.

The release candidate features a diverse distribution of changes across various subsystems:

1. Filesystems: Approximately one-third of the patchset (about 33%) is dedicated to filesystem fixes, including Ceph, SMB client, NFS, EROFS, and Btrfs. These updates address issues such as compressed stats leaks, handling of LZO compression levels, corruption reading compressed ranges, and inode xarray races leading to subvolume deletion lockups.
2. Drivers: Another third (about 33%) addresses driver fixes, with a significant portion dedicated to GPU drivers. Other miscellaneous drivers also see fixes for various issues.
3. Core Networking, CPU Speculation Mitigations, Documentation Updates, Selftest Enhancements, and Minor Adjustments: The final third of the patchset covers a range of other areas, including core networking components, CPU speculation mitigations, documentation updates, selftest enhancements, and various minor adjustments.

The changelog highlights contributions from numerous developers across various kernel subsystems:

Filesystems

• Btrfs: Significant updates include fixes for compressed stats leaks, handling of LZO compression levels, accepting and ignoring compression levels, preventing corruption reading compressed ranges, and addressing inode xarray races leading to subvolume deletion lockups.
• Ceph: Fixes address race conditions in parent validation and message sending, as well as invalid accesses to connection info.
• EROFS: Includes fixes for invalid algorithms for encoded extents and long xattr name prefix placement, alongside runtime warnings on truncate operations.
• FUSE: Contributes fixes for validation of r_parent, allowing mapping of non-regular backing files, using consistent rules for file handle decoding, blocking access to folio overlimit, fixing page faults for DAX pages, reflecting cached blocksize, fixing i_blkbits for iomap partial writes, and preventing overflows in copy_file_range return values.
• NFS: Includes fixes for O_DIRECT IO serialization with truncate, fallocate, clone range, and copy range, protection against 'eof page pollution', marking folios up-to-date correctly, and serializing data for NFSv4.2 copy offload and clone operations.
• OCFS2: Addresses recursive semaphore deadlocks in fiemap calls.

Drivers

• AMDGPU: Fixes include memory leak in fence cleanup, using udelay over fsleep, VCN4 IB parsing, VCN context limiting for AV1.
• XE: Updates address Wa_13011645652 extension, BOS back to VRAM after eviction, PM notifier handling, blocking exec/rebind during suspend/hibernate, configfs updates.
• Nouveau: Removes waitque for sched teardown.
• Mediatek DRM: Addresses OF node use-after-free and driver data cleanup.
• Panthor: Validates group queue count.

Networking

• Core Networking Components: Updates include fixes for hsr port iteration and RCU locking, netfilter changes for nft_set_bitmap, nft_set_pipapo, nft_set_rbtree, and nf_tables base_seq handling.
• PHY Handling: Fixes address phy_uses_state_machine and incorrect types in struct kernel_ethtool_ts_info.
• SMB Client: Addresses compound alignment with encryption and data loss during renames.
• CAN Subsystem: Includes implementation of NETDEV_UNREGISTER, immediate j1939_priv_put calls on failure, and undoing increments when j1939_local_ecu_get fails.

BPF (Berkeley Packet Filter)

• Several fixes and improvements are present, including out-of-bounds dynptr writes, extending the crypto_sanity selftest, disabling page_pool direct XDP_RETURN, updating maintainers, fixing LLVM warnings, allowing fallback to the interpreter for specific programs, rejecting bpf_timer for PREEMPT_RT, and skipping timer cases where bpf_timer is not supported.

Memory Management

• Updates include fixes for regressions in vrm->new_addr checks, page fault handling for DAX pages, hugetlb_lock in unmap operations, hwpoisoned large folio handling in migrate_range, memory_failure fixes for redundant updates on poisoned pages, and respecting GFP masks in kasan_populate_vmalloc.
• DAMON (Data-driven Autonomous Memory REclamation): Fixes address divide-by-zero in apply_parameters, setting quota->charged_from to jiffies, and use-after-free in state_show.

CPU Vulnerabilities and Architecture

• Documentation and mitigation for VMSCAPE vulnerability are added, including conditional IBPB mitigation, enabling the mitigation, moving cpu_bugs_smt_update, warning when STIBP is disabled with SMT, and adding older Intel CPUs to affected lists.
• x86 Topology: Updates include always trying cpu_parse_topology_ext on AMD/Hygon.
• Kexec Buffer Initialization: Standardized across arm64, RISC-V, and s390.

Other Subsystems

• Tracing: Fixes address potential page faults during preempt_disable, silence warnings on chunk allocation failure, and removing redundant __GFP_NOWARN.
• Selftests: Updated across various areas including FS, net, and BPF.
• DT Bindings: Updates address serial, DMA, and PHY configurations.
• General Infrastructure Changes: Include compiler-clang macros, percpu race fixes, and kernel ethtool ts_info type corrections.

MAINTAINERS File Updates

• Updates are present for various subsystems.

Linux kernel 6.17-rc6 released

Linux kernel version 6.17-rc6 is now available:

Full source: https://git.kernel.org/torvalds/t/linux-6.17-rc6.tar.gz
Patch: https://git.kernel.org/torvalds/p/v6.17-rc6/v6.16

You can view the summary of the changes at the following URL:
https://git.kernel.org/torvalds/ds/v6.17-rc6/v6.17-rc5