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From:   Andrey Konovalov <andreyknvl@gmail.com>
Date:   Mon, 5 Jul 2021 13:23:17 +0200
Message-ID: <CA+fCnZfKAZuy9oyDpTgNUTcNz5gnfHpJK5WN-yBNDV5VF8cq0g@mail.gmail.com>
Subject: Re: [PATCH v6 2/2] kasan: Add memzero int for unaligned size at DEBUG
To:     Marco Elver <elver@google.com>
Cc:     yee.lee@mediatek.com, LKML <linux-kernel@vger.kernel.org>,
        nicholas.tang@mediatek.com,
        Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com>,
        chinwen.chang@mediatek.com,
        Andrey Ryabinin <ryabinin.a.a@gmail.com>,
        Alexander Potapenko <glider@google.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        "open list:KASAN" <kasan-dev@googlegroups.com>,
        "open list:MEMORY MANAGEMENT" <linux-mm@kvack.org>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-arm-kernel@lists.infradead.org>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-mediatek@lists.infradead.org>
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On Mon, Jul 5, 2021 at 1:18 PM Marco Elver <elver@google.com> wrote:
>
> On Mon, 5 Jul 2021 at 13:12, Andrey Konovalov <andreyknvl@gmail.com> wrote:
> [...]
> > > +       /*
> > > +        * Explicitly initialize the memory with the precise object size to
> > > +        * avoid overwriting the SLAB redzone. This disables initialization in
> > > +        * the arch code and may thus lead to performance penalty. The penalty
> > > +        * is accepted since SLAB redzones aren't enabled in production builds.
> > > +        */
> > > +       if (__slub_debug_enabled() &&
> >
> > What happened to slub_debug_enabled_unlikely()? Was it renamed? Why? I
> > didn't receive patch #1 of v6 (nor of v5).
>
> Somebody had the same idea with the helper:
> https://lkml.kernel.org/r/YOKsC75kJfCZwySD@elver.google.com
> and Matthew didn't like the _unlikely() prefix.
>
> Which meant we should just move the existing helper introduced in the
> merge window.
>
> Patch 1/2: https://lkml.kernel.org/r/20210705103229.8505-2-yee.lee@mediatek.com

Got it. Thank you, Marco!