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Date: Thu, 21 May 2026 13:41:41 +0200
From: Christian Brauner <brauner@kernel.org>
To: Arnd Bergmann <arnd@kernel.org>
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>, 
	Arnd Bergmann <arnd@arndb.de>, Jan Kara <jack@suse.cz>, avivdaum <aviv.daum@gmail.com>, 
	Adi Nata <adinata.softwareengineer@gmail.com>, Andrew Morton <akpm@linux-foundation.org>, 
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] fat: avoid stack overflow warning
Message-ID: <20260521-quark-klatschen-cf7a2a18ba34@brauner>
References: <20260515204456.2692208-1-arnd@kernel.org>
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In-Reply-To: <20260515204456.2692208-1-arnd@kernel.org>

On Fri, May 15, 2026 at 10:44:46PM +0200, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> Building the fat kunit tests on with -fsanitize=alignment
> reveals some rather excessive stack usage:
> 
> fs/fat/fat_test.c: In function 'fat_clus_to_blknr_test':
> fs/fat/fat_test.c:33:1: error: the frame size of 4736 bytes is larger than 1536 bytes [-Werror=frame-larger-than=]
>    33 | }
>       | ^
> fs/fat/fat_test.c: In function 'fat_get_blknr_offset_test':
> fs/fat/fat_test.c:52:1: error: the frame size of 4800 bytes is larger than 1536 bytes [-Werror=frame-larger-than=]
> 
> The problem is clearly related to the on-stack copy of a local
> msdos_sb_info structure. Avoid this by making that copy
> 'static const' and changing the called functions to accept
> a constant input.
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---

What is this based on, Arnd? I'm getting errors applying this.