Re: kernel BUG at kernel/futex.c:679 on v4.13-rc3-ish on arm64

[Linus Torvalds]

On Tue, Aug 8, 2017 at 8:41 AM, Mark Rutland <mark.rutland@xxxxxxx> wrote:
>
> With my __BUG_FLAGS() issue corrected, the WARN_ON_ONCE() fires once,
> and everything else seems fine. I'll have a go with additional debug
> enabled just in case.

Ok, great, a - mostly - false alarm.

I do wonder if we should just remove even that WARN_ON_ONCE() - I
think it was added to be careful, and the code seems to do the right
thing.

The second WARN_ON_ONCE() (that is marked as "should be impossible")
we might as well leave around. If that one triggers, it's a lot more
interesting.

Mel? No hurry - the nice thing about WARN_ON_ONCE() is that it's just
a single note so it's neither killing the machine(*) nor causing any
real problems.

                Linus

(*) when it works, but presumably it is now fixed on ARM64, and I
expect I'll see a pull request ;).