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From:   Marco Elver <elver@google.com>
Date:   Tue, 19 Oct 2021 16:14:05 +0200
Message-ID: <CANpmjNMMQUHhFTdaqfx6HErnv0aXkCJn+eBGN-kfeznN8H+f3g@mail.gmail.com>
Subject: Re: [PATCH] kasan: add kasan mode messages when kasan init
To:     Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com>
Cc:     Andrey Ryabinin <ryabinin.a.a@gmail.com>,
        Alexander Potapenko <glider@google.com>,
        Andrey Konovalov <andreyknvl@gmail.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        chinwen.chang@mediatek.com, yee.lee@mediatek.com,
        nicholas.tang@mediatek.com, kasan-dev@googlegroups.com,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, linux-mediatek@lists.infradead.org
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On Tue, 19 Oct 2021 at 14:04, Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com> wrote:
>
> There are multiple kasan modes. It make sense that we add some messages
> to know which kasan mode is when booting up. see [1].
>
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=212195 [1]
> Signed-off-by: Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com>

Looks good, however, you need to rebase to -next because of "kasan:
Extend KASAN mode kernel parameter"...

> ---
>  arch/arm64/mm/kasan_init.c | 2 +-
>  mm/kasan/hw_tags.c         | 4 +++-
>  mm/kasan/sw_tags.c         | 2 +-
>  3 files changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c
> index 61b52a92b8b6..b4e78beac285 100644
> --- a/arch/arm64/mm/kasan_init.c
> +++ b/arch/arm64/mm/kasan_init.c
> @@ -293,7 +293,7 @@ void __init kasan_init(void)
>         kasan_init_depth();
>  #if defined(CONFIG_KASAN_GENERIC)
>         /* CONFIG_KASAN_SW_TAGS also requires kasan_init_sw_tags(). */
> -       pr_info("KernelAddressSanitizer initialized\n");
> +       pr_info("KernelAddressSanitizer initialized (generic)\n");
>  #endif
>  }
>
> diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c
> index 05d1e9460e2e..3e28ecbe1d8f 100644
> --- a/mm/kasan/hw_tags.c
> +++ b/mm/kasan/hw_tags.c
> @@ -168,7 +168,9 @@ void __init kasan_init_hw_tags(void)
>                 break;
>         }
>
> -       pr_info("KernelAddressSanitizer initialized\n");
> +       pr_info("KernelAddressSanitizer initialized (hw-tags, mode=%s, stacktrace=%s)\n",
> +               kasan_flag_async ? "async" : "sync",

... which means this will have a 3rd option "asymm".

> +               kasan_stack_collection_enabled() ? "on" : "off");
>  }
>
>  void kasan_alloc_pages(struct page *page, unsigned int order, gfp_t flags)
> diff --git a/mm/kasan/sw_tags.c b/mm/kasan/sw_tags.c
> index bd3f540feb47..77f13f391b57 100644
> --- a/mm/kasan/sw_tags.c
> +++ b/mm/kasan/sw_tags.c
> @@ -42,7 +42,7 @@ void __init kasan_init_sw_tags(void)
>         for_each_possible_cpu(cpu)
>                 per_cpu(prng_state, cpu) = (u32)get_cycles();
>
> -       pr_info("KernelAddressSanitizer initialized\n");
> +       pr_info("KernelAddressSanitizer initialized (sw-tags)\n");
>  }
>
>  /*
> --
> 2.18.0