From mboxrd@z Thu Jan  1 00:00:00 1970
From: Kees Cook <keescook-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
Subject: Re: [PATCH v2][next] cgroup: Avoid -Wstringop-overflow warnings
Date: Wed, 16 Aug 2023 13:57:16 -0700
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To: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: "Gustavo A. R. Silva" <gustavoars-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Zefan Li <lizefan.x-EC8Uxl6Npydl57MIdRCFDg@public.gmane.org>, Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-hardening-u79uwXL29TY76Z2rM5mHXA@public.gmane.org

On Wed, Aug 16, 2023 at 10:51:12AM -1000, Tejun Heo wrote:
> Hello,
> 
> On Wed, Aug 16, 2023 at 02:50:16PM -0600, Gustavo A. R. Silva wrote:
> > Change the notation from pointer-to-array to pointer-to-pointer.
> > With this, we avoid the compiler complaining about trying
> > to access a region of size zero as an argument during function
> > calls.
> 
> Haha, I thought the functions were actually accessing the memory. This can't
> be an intended behavior on the compiler's side, right?

I think it's a result of inlining -- the compiler ends up with a case
where it looks like it might be possible to index a zero-sized array,
but it is "accidentally safe".

-- 
Kees Cook