How do I annotate seq-cst atomic fences for the thread sanitizer?

Question

I learned that TSAN doesn't understand std::atomic_thread_fence, and to fix it, you need to tell TSAN which atomic variables are affected by the fence, by putting __tsan_acquire(void *) and __tsan_release(void *) next to it (for acquire and release fences respectively).

But what about seq-cst fences? As I understand, they're more strict than acq-rel fences, so acq-rel annotations might not be enough?

I'm not too familiar with different memory orders, so I might be missing something.

Answer 1

@dvyukov on Github confirmed the __tsan_acquire+__tsan_release instrumentation (same as for acq-rel fences) should be enough.

I'm not sure if it means that TSAN doesn't distinguish between seq-cst and acq-rel operations in general, or not.