Re: [PATCH] Fix data race in mark_rt_mutex_waiters

On Mon, Jan 23, 2023 at 08:40:14AM -0800, Paul E. McKenney wrote:

In the case, the value read is passed into cmpxchg_relaxed(), which checks the value against memory. In this case, as Arjan noted, the only compiler-and-silicon difference between data_race() and READ_ONCE() is that use of data_race() might allow the compiler to do things like tear the load, thus forcing the occasional spurious cmpxchg_relaxed() failure.

Is it possible in theory for a torn load to cause a spurious cmpxchg_relaxed() success? Or would that not matter here?

Alan