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From:   Marco Elver <elver@google.com>
Date:   Thu, 14 Jan 2021 20:56:21 +0100
Message-ID: <CANpmjNNGBCrTwcm=3wrXfdy5A5=3Vd-MVdLd8BBzHRseykFX6Q@mail.gmail.com>
Subject: Re: [PATCH v2 11/14] kasan: fix bug detection via ksize for HW_TAGS mode
To:     Andrey Konovalov <andreyknvl@google.com>
Cc:     Catalin Marinas <catalin.marinas@arm.com>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Alexander Potapenko <glider@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Will Deacon <will.deacon@arm.com>,
        Andrey Ryabinin <aryabinin@virtuozzo.com>,
        Peter Collingbourne <pcc@google.com>,
        Evgenii Stepanov <eugenis@google.com>,
        Branislav Rankov <Branislav.Rankov@arm.com>,
        Kevin Brodsky <kevin.brodsky@arm.com>,
        kasan-dev <kasan-dev@googlegroups.com>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Linux Memory Management List <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>
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On Thu, 14 Jan 2021 at 19:01, 'Andrey Konovalov' via kasan-dev
<kasan-dev@googlegroups.com> wrote:
> On Wed, Jan 13, 2021 at 5:54 PM Marco Elver <elver@google.com> wrote:
> >
> > > +/*
> > > + * Unlike kasan_check_read/write(), kasan_check_byte() is performed even for
> > > + * the hardware tag-based mode that doesn't rely on compiler instrumentation.
> > > + */
> > > +bool __kasan_check_byte(const void *addr, unsigned long ip);
> > > +static __always_inline bool kasan_check_byte(const void *addr, unsigned long ip)
> > > +{
> > > +       if (kasan_enabled())
> > > +               return __kasan_check_byte(addr, ip);
> > > +       return true;
> > > +}
> >
> > Why was this not added to kasan-checks.h? I'd assume including all of
> > kasan.h is also undesirable for tag-based modes if we just want to do
> > a kasan_check_byte().
>
> It requires kasan_enabled() definition. I can move both to
> kasan-checks.h if you prefer. However, the only place where
> kasan_check_byte() is currently used includes kasan.h anyway.

Hmm, if it makes too much of a mess, let's just leave as-is.

Thanks,
-- Marco