CVE-2026-23018

A potential deadlock vulnerability was found in the Linux kernel's Btrfs filesystem. In btrfs_read_locked_inode(), the function calls btrfs_init_file_extent_tree() while holding a read-locked leaf from the subvolume tree. Since btrfs_init_file_extent_tree() may perform GFP_KERNEL memory allocation, it can trigger memory reclaim which creates a circular lock dependency between the btree lock, fs_reclaim, and the delayed_node mutex.

This is a lockdep-detected circular locking dependency that can theoretically cause a deadlock under memory pressure. The chain involves: fs_reclaim → btrfs-tree lock → delayed_node mutex → fs_reclaim. While lockdep warns about this pattern, triggering an actual deadlock requires specific memory pressure conditions during inode lookup operations.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.