Linux CVE-2025-71268

The vulnerability resides in the btrfs (B-tree filesystem) subsystem of the Linux kernel, specifically in the __cow_file_range_inline() function responsible for copy-on-write operations when inserting inline extents. When the function fails to allocate a path structure or join a transaction during inline extent insertion, it returns without calling btrfs_qgroup_free_data() to release reserved quota group (qgroup) data resources that were allocated earlier in the execution path. This is a classic resource leak (CWE-404: Improper Resource Shutdown or Release) where allocated kernel memory accounting structures remain reserved but never freed. The qgroup subsystem in btrfs is used for quota management and accounting; failing to return reserved data results in permanent loss of available quota space within the filesystem context. The affected product is the Linux kernel itself (CPE: cpe:2.3:a:linux:linux:*:*:*:*:*:*:*:*), impacting all distributions that include vulnerable btrfs code.