Re: [PATCH v2] x86: s/READ_ONCE_NOCHECK/READ_ONCE/ in arch_atomic[64]_read()

[Arnd Bergmann]

On Wed, Mar 22, 2017 at 1:57 PM, Dmitry Vyukov <dvyukov@xxxxxxxxxx> wrote:
> Two problems was reported with READ_ONCE_NOCHECK in arch_atomic_read:
> 1. Andrey Ryabinin reported significant binary size increase
> (+400K of text). READ_ONCE_NOCHECK is intentionally compiled to
> non-inlined function call, and I counted 640 copies of it in my vmlinux.
> 2. Arnd Bergmann reported a new splat of too large frame sizes.
>
> A single inlined KASAN check is very cheap, a non-inlined function
> call with KASAN/KCOV instrumentation can easily be more expensive.
>
> Switch to READ_ONCE() in arch_atomic[64]_read().
>
> Signed-off-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
> Reported-by: Arnd Bergmann <arnd@xxxxxxxx>
> Reported-by: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
> Cc: Mark Rutland <mark.rutland@xxxxxxx>
> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Cc: Will Deacon <will.deacon@xxxxxxx>
> Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: linux-mm@xxxxxxxxx
> Cc: x86@xxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Cc: kasan-dev@xxxxxxxxxxxxxxxx
> Signed-off-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
>

Acked-by: Arnd Bergmann <arnd@xxxxxxxx>