Re: [PATCH 7.1.y, 6.18.y, 6.12.y] futex: Prevent robust futex exit race some more

> commit 6d4514ca9cdf61fec4ec634cf50386f6f7e69748 upstream.
>
> A robust futex unlock stores 0 over the whole futex value - wiping
> FUTEX_WAITERS - and wakes a single waiter. That wakeup is a one-shot
> notification: the protocol relies on its recipient to either acquire the
> futex (and eventually unlock while aware of the remaining contention) or
> re-arm FUTEX_WAITERS before sleeping again.

Queued for all the active stable trees (7.1 down to 5.10), thanks. The older
ones needed futex_wake()'s signature adapted; the logic is unchanged.

-- 
Thanks,
Sasha