Re: [PATCH v5 00/18] Rework READ_ONCE() to improve codegen

From: Peter Zijlstra
Date: Fri May 15 2020 - 10:07:54 EST


On Fri, May 15, 2020 at 01:55:43PM +0000, David Laight wrote:
> From: Peter Zijlstra
> > Sent: 14 May 2020 15:25
> ..
> > Exact same requirements, KASAN even has the data_race() problem through
> > READ_ONCE_NOCHECK(), UBSAN doesn't and might be simpler because of it.
>
> What happens if you implement READ_ONCE_NOCHECK() with an
> asm() statement containing a memory load?
>
> Is that enough to kill all the instrumentation?

You'll have to implement it for all archs, but yes, I think that ought
to work.