filelock: StrictSoftFileLock and SoftReadWriteLock adopt a protocol directory another user created first, losing mutual exclusion

filelock: SoftReadWriteLock holder refresh writes through a hard link and hangs on a named pipe that another local user renames over its record

filelock: SoftReadWriteLock follows a lock tree swapped in after its first acquire and writes lock records into directories of the user running the lock

filelock: SoftFileLock evicts a fresh lock file whose watched age another local user's pre-dated file passed on through inode reuse

filelock: UnixFileLock truncates and chmods any regular file another user renames or hard-links onto the lock path

filelock: Symlink swap during SoftFileLock's writability check leaks whether a path exists and is writable by the lock taker

filelock ReadWriteLock: a crafted lock database makes every acquire stall or hang regardless of timeout