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From:   Andrey Konovalov <andreyknvl@gmail.com>
Date:   Tue, 20 Jun 2023 13:45:25 +0200
Message-ID: <CA+fCnZccdLNqtxubVVtGPTOXcSoYfpM9CHk-nrYsZK7csC77Eg@mail.gmail.com>
Subject: Re: [PATCH] kasan: add support for kasan.fault=panic_on_write
To:     Marco Elver <elver@google.com>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Alexander Potapenko <glider@google.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Taras Madan <tarasmadan@google.com>,
        Aleksandr Nogikh <nogikh@google.com>,
        Andrey Ryabinin <ryabinin.a.a@gmail.com>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        Jonathan Corbet <corbet@lwn.net>, kasan-dev@googlegroups.com,
        linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, Catalin Marinas <catalin.marinas@arm.com>
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On Tue, Jun 20, 2023 at 1:33=E2=80=AFPM Marco Elver <elver@google.com> wrot=
e:
>
> > On a related note, it looks like we have a typo in KASAN
> > documentation: it states that asymm mode detects reads synchronously,
> > and writes - asynchronously. Should be the reverse.
>
> This says the documentation is correct, and it's actually called for
> writes: https://docs.kernel.org/arm64/memory-tagging-extension.html#tag-c=
heck-faults
>
> Who is right?

Ah, right. I did a quick google to check when I was writing the
response and found this: https://lwn.net/Articles/882963/. But looks
like that cover letter is wrong and the documentation is right. I
wonder what the point of the asymmetric mode is then.

So the current code that you have should work perfectly. The only
change I'd like to see is in the documentation.

Thanks!