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From:   Geert Uytterhoeven <geert@linux-m68k.org>
Date:   Wed, 18 Oct 2023 20:29:07 +0200
Message-ID: <CAMuHMdXSzMJe1zyJu1HkxWggTKJj_sxkPOejjbdRjg3FeFTVHQ@mail.gmail.com>
Subject: Re: [PATCH] lib/Kconfig.debug: disable FRAME_WARN for kasan and kcsan
To:     Hamza Mahfooz <hamza.mahfooz@amd.com>
Cc:     linux-kernel@vger.kernel.org,
        Rodrigo Siqueira <rodrigo.siqueira@amd.com>,
        Harry Wentland <harry.wentland@amd.com>,
        Alex Deucher <alexander.deucher@amd.com>,
        Arnd Bergmann <arnd@arndb.de>, stable@vger.kernel.org,
        Miguel Ojeda <ojeda@kernel.org>,
        Alex Gaynor <alex.gaynor@gmail.com>,
        Wedson Almeida Filho <wedsonaf@gmail.com>,
        Boqun Feng <boqun.feng@gmail.com>, Gary Guo <gary@garyguo.net>,
        =?UTF-8?Q?Bj=C3=B6rn_Roy_Baron?= <bjorn3_gh@protonmail.com>,
        Nick Terrell <terrelln@fb.com>,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Tom Rix <trix@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        "Masami Hiramatsu (Google)" <mhiramat@kernel.org>,
        Randy Dunlap <rdunlap@infradead.org>,
        Kees Cook <keescook@chromium.org>,
        Zhaoyang Huang <zhaoyang.huang@unisoc.com>,
        Li Hua <hucool.lihua@huawei.com>,
        Alexander Potapenko <glider@google.com>,
        Geert Uytterhoeven <geert+renesas@glider.be>,
        Rae Moar <rmoar@google.com>, rust-for-linux@vger.kernel.org,
        bpf@vger.kernel.org, llvm@lists.linux.dev
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Hi Hamza,

On Wed, Oct 18, 2023 at 8:24 PM Hamza Mahfooz <hamza.mahfooz@amd.com> wrote:
> With every release of LLVM, both of these sanitizers eat up more and
> more of the stack. So, set FRAME_WARN to 0 if either of them is enabled
> for a given build.
>
> Cc: stable@vger.kernel.org
> Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>

Thanks for your patch!

> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -429,11 +429,10 @@ endif # DEBUG_INFO
>  config FRAME_WARN
>         int "Warn for stack frames larger than"
>         range 0 8192
> -       default 0 if KMSAN
> +       default 0 if KASAN || KCSAN || KMSAN

Are kernels with KASAN || KCSAN || KMSAN enabled supposed to be bootable?
Stack overflows do cause crashes.

>         default 2048 if GCC_PLUGIN_LATENT_ENTROPY
>         default 2048 if PARISC
>         default 1536 if (!64BIT && XTENSA)
> -       default 1280 if KASAN && !64BIT
>         default 1024 if !64BIT
>         default 2048 if 64BIT
>         help

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds