Re: [PATCH v2 2/2] Kconfig.debug: Provide a little extra FRAME_WARN leeway when KASAN is enabled

From: Lee Jones <lee@kernel.org>
To: arnd@arndb.de, akpm@linux-foundation.org, nathan@kernel.org,
	maarten.lankhorst@linux.intel.com, mripard@kernel.org,
	tzimmermann@suse.de, airlied@gmail.com, daniel@ffwll.ch,
	ndesaulniers@google.com, trix@redhat.com, harry.wentland@amd.com,
	sunpeng.li@amd.com, Rodrigo.Siqueira@amd.com,
	alexander.deucher@amd.com, christian.koenig@amd.com,
	Xinhui.Pan@amd.com
Cc: linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, llvm@lists.linux.dev,
	amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org
Subject: Re: [PATCH v2 2/2] Kconfig.debug: Provide a little extra FRAME_WARN leeway when KASAN is enabled
Date: Fri, 25 Nov 2022 13:40:23 +0000	[thread overview]
Message-ID: <Y4DFx20YXDLcuVJm@google.com> (raw)
In-Reply-To: <20221125120750.3537134-3-lee@kernel.org>

On Fri, 25 Nov 2022, Lee Jones wrote:

> When enabled, KASAN enlarges function's stack-frames.  Pushing quite a
> few over the current threshold.  This can mainly be seen on 32-bit
> architectures where the present limit (when !GCC) is a lowly
> 1024-Bytes.
> 
> Signed-off-by: Lee Jones <lee@kernel.org>
> ---
>  lib/Kconfig.debug | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> index c3c0b077ade33..82d475168db95 100644
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -399,6 +399,7 @@ config FRAME_WARN
>  	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

Note this also fixes 61 warnings when

  (GCC && !GCC_PLUGIN_LATENT_ENTROPY)

... which as Arnd says should not be enabled by default.  We'll
address that issue once this set has been applied.

-- 
Lee Jones [李琼斯]