You still have a critical section; the cacheline is in an exclusive mode during the change. LL/SC operates on top the cache sharing protocols, just like everything else. Your wikipedia link even refers to that: "Typically, CPUs track the load-linked address at a cache-line or other granularity [...]". MESI and friends are that mechanism.

What lock-free means in this case is that an OS level thread freezing doesn't prevent global progress. That's true on the abstraction level of typical programming, but grandparent is very much correct:

> Really, "lock free" programming is just locking critical sections with lower level hardware primitives.