linux-kernel - Re: [PATCH] kbuild: Enable GCC diagnostic context for value-tracking warnings

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Message-ID: <CANiq72=tzUPrDd2=GBnqxm_PmjF9nT3iVJ5ZT6AiZQqkjvdH_g@mail.gmail.com>
Date: Thu, 20 Nov 2025 09:17:16 +0100
From: Miguel Ojeda <miguel.ojeda.sandonis@...il.com>
To: Kees Cook <kees@...nel.org>
Cc: "Gustavo A . R . Silva" <gustavoars@...nel.org>, Nathan Chancellor <nathan@...nel.org>, 
	Nicolas Schier <nicolas.schier@...ux.dev>, Masahiro Yamada <masahiroy@...nel.org>, 
	Miguel Ojeda <ojeda@...nel.org>, linux-kbuild@...r.kernel.org, 
	Thomas Weißschuh <thomas.weissschuh@...utronix.de>, 
	Tamir Duberstein <tamird@...il.com>, linux-kernel@...r.kernel.org, 
	linux-hardening@...r.kernel.org
Subject: Re: [PATCH] kbuild: Enable GCC diagnostic context for value-tracking warnings

On Wed, Nov 19, 2025 at 11:44 PM Kees Cook <kees@...nel.org> wrote:
>
> Enable GCC 16's coming "-fdiagnostics-show-context=2" option[1] to
> provide enhanced diagnostic information for value-tracking warnings, which
> displays the control flow chain leading to the diagnostic. This covers our

> existing use of -Wrestrict and -Wstringop-overread, and gets us closer to
> enabling -Warray-bounds, -Wstringop-overflow, and -Wstringop-truncation.

I am probably missing some context, but in what sense gets us closer?
Do you mean it will make it easier to understand those when we enable
them? i.e. we still can't enable them until the minimum is upgraded,
right?

Apart from that, it looks like a nice improvement on the output from
the PR examples -- I didn't test it, but the patch itself looks fine
of course:

Reviewed-by: Miguel Ojeda <ojeda@...nel.org>

Thanks!

Cheers,
Miguel