[Dylan16807]

On what basis are you saying the interrupt messes it up?

The post directly says that if a migration doesn't happen, then nothing goes wrong.

What messes up is when you do the barrier-needing instructions on one core, and a memory barrier on a completely different core. Which seems pretty expected to me.

If the thing you're describing happens, that does sound like a hardware bug, but I don't see where you got that description from.

[ajross]

> On what basis are you saying the interrupt messes it up?

Because nothing else makes sense. The code as posted in the linked article does not seem to have an ordering violation that I can see. The linked blog just asserts that it's there, but AFAICT it isn't unless there's a symmetric ordering bug in the putative context switch code that isn't presented.

[Dylan16807]

The problem is very simple, isn't it? There are instructions that need a memory barrier after them. If the thread leaves the core, then from the view of that core no memory barrier happens.

And it's a particular kind of memory barrier that nothing else does incidentally.