linux-kernel - Re: [PATCH 1/1] alloc_tag: work around clang-14 issue with __builtin_object

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Message-ID: <202502051327.AE8C0706@keescook>
Date: Wed, 5 Feb 2025 13:28:36 -0800
From: Kees Cook <kees@...nel.org>
To: Kent Overstreet <kent.overstreet@...ux.dev>
Cc: Suren Baghdasaryan <surenb@...gle.com>, akpm@...ux-foundation.org,
	nathan@...nel.org, ndesaulniers@...gle.com, morbo@...gle.com,
	justinstitt@...gle.com, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org, llvm@...ts.linux.dev,
	kernel test robot <lkp@...el.com>
Subject: Re: [PATCH 1/1] alloc_tag: work around clang-14 issue with
 __builtin_object_size()

On Wed, Feb 05, 2025 at 03:16:12PM -0500, Kent Overstreet wrote:
> ARRAY_SIZE() is sizeof() underneath, just used creatively to guarantee
> that the input is an array - although that property is probably what we
> want here, since strtomem_pad() really only makes sense on static or
> flex-arrays, no?

Exactly. strtomem*/memtostr* are very picky about the destination being
compile-time sized, so sizeof() under the hood seems correct. I'm making
my way through testing a patch now...

-- 
Kees Cook