Race Condition in Btrfs Subvolume Deletion in Linux Kernel

CVE-2025-39884

What is CVE-2025-39884?

A race condition in the Linux Kernel affects the Btrfs file system's subvolume deletion process. This vulnerability arises from a timing issue between inode eviction and caching, leading to instances where a live struct btrfs_inode may be missing from the root directory's inode array. If concurrent operations attempt to access the inode during this window, it can result in a scenario where subsequent calls to btrfs_iget() recreate an entry that is then removed during eviction, potentially leading to soft lockups in production environments. The fix ensures that the xarray entry is deleted only when it matches the intended inode, mitigating risks associated with premature deletions and infinite loops during inode processing.

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