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Date:   Thu, 1 Oct 2020 19:47:01 +0200
From:   elver@google.com
To:     Andrey Konovalov <andreyknvl@google.com>
Cc:     Dmitry Vyukov <dvyukov@google.com>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        kasan-dev@googlegroups.com,
        Andrey Ryabinin <aryabinin@virtuozzo.com>,
        Alexander Potapenko <glider@google.com>,
        Evgenii Stepanov <eugenis@google.com>,
        Elena Petrova <lenaptr@google.com>,
        Branislav Rankov <Branislav.Rankov@arm.com>,
        Kevin Brodsky <kevin.brodsky@arm.com>,
        Will Deacon <will.deacon@arm.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 18/39] kasan: kasan_non_canonical_hook only for
 software modes
Message-ID: <20201001174701.GN4162920@elver.google.com>
References: <cover.1600987622.git.andreyknvl@google.com>
 <ff0f9a3bab9d2b99580f436121812d1eee560b44.1600987622.git.andreyknvl@google.com>
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On Fri, Sep 25, 2020 at 12:50AM +0200, Andrey Konovalov wrote:
> This is a preparatory commit for the upcoming addition of a new hardware
> tag-based (MTE-based) KASAN mode.
> 
> kasan_non_canonical_hook() is only applicable to KASAN modes that use
> shadow memory, and won't be needed for hardware tag-based KASAN.
> 
> No functional changes for software modes.
> 
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>

Reviewed-by: Marco Elver <elver@google.com>

> ---
> Change-Id: Icc9f5ef100a2e86f3a4214a0c3131a68266181b2
> ---
>  mm/kasan/report.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/mm/kasan/report.c b/mm/kasan/report.c
> index 9e4d539d62f4..67aa30b45805 100644
> --- a/mm/kasan/report.c
> +++ b/mm/kasan/report.c
> @@ -371,7 +371,8 @@ bool kasan_report(unsigned long addr, size_t size, bool is_write,
>  	return ret;
>  }
>  
> -#ifdef CONFIG_KASAN_INLINE
> +#if (defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)) && \
> +	defined(CONFIG_KASAN_INLINE)
>  /*
>   * With CONFIG_KASAN_INLINE, accesses to bogus pointers (outside the high
>   * canonical half of the address space) cause out-of-bounds shadow memory reads
> -- 
> 2.28.0.681.g6f77f65b4e-goog
>