Linux Kernel CVE-2026-72100

dm-integrity is a Linux kernel device mapper (DM) target that appends per-block cryptographic checksums to a block device, providing at-rest integrity verification. It is not enabled by default and must be explicitly provisioned by an administrator. The vulnerability lives in the I/O submission path: before mapping a bio, the module calls dm_integrity_check_limits to validate that the request falls within configured extents. When this check fails, the original code returned DM_MAPIO_KILL (drop the bio) without first releasing the range lock acquired earlier in the same call frame. Because that range lock serializes concurrent access to integrity metadata for overlapping device regions, holding it permanently causes all subsequent I/O against overlapping ranges to deadlock indefinitely. The root cause is a classic error-path resource leak - an early exit that bypasses the unlock path. No CWE is formally assigned in the NVD record; the closest applicable CWEs would be CWE-667 (Improper Locking) or CWE-833 (Deadlock). Affected kernel commits span from fb0987682c629c1d2c476f35f6fde405a5e304a4 up to each respective stable-tree fix commit.