CVE-2026-46130 dm-verity-fec: fix reading parity bytes split across blocks (take 3)

In the Linux kernel, the following vulnerability has been resolved: dm-verity-fec: fix reading parity bytes split across blocks take 3 fecdecodebufs assumes that the parity bytes of the first RS codeword it decodes are never split across parity blocks. This assumption is false. Consider...