In the Linux kernel, the following vulnerability has been resolved: smb: client: split cachedfid bitfields to avoid shared-byte RMW races isopen, haslease and onlist are stored in the same bitfield byte in struct cachedfid but are updated in different code paths that may run concurrently. Bitfield assignments generate byte read–modify–write operations (e.g. orb $mask, addr on x8664), so updating one flag can restore stale values of the others. A possible interleaving is: CPU1: load old byte (haslease=1, onlist=1) CPU2: clear both flags (store 0) CPU1: RMW store (old | IS_OPEN) -> reintroduces cleared bits To avoid this class of races, convert these flags to separate bool fields.