linux-kernel - Re: [PATCH v4 0/2] kbuild: remove gcc's -Wtype-limits

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Message-ID: <aVutfSk4PWbGac_Q@levanger>
Date: Mon, 5 Jan 2026 13:24:29 +0100
From: Nicolas Schier <nsc@...nel.org>
To: Nathan Chancellor <nathan@...nel.org>
Cc: Vincent Mailhol <mailhol@...nel.org>,
	Nick Desaulniers <nick.desaulniers+lkml@...il.com>,
	Bill Wendling <morbo@...gle.com>,
	Justin Stitt <justinstitt@...gle.com>,
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
	Maxime Ripard <mripard@...nel.org>,
	Thomas Zimmermann <tzimmermann@...e.de>,
	David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
	Chris Mason <clm@...com>, David Sterba <dsterba@...e.com>,
	Kees Cook <kees@...nel.org>,
	"Gustavo A. R. Silva" <gustavoars@...nel.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	linux-kbuild@...r.kernel.org, linux-sparse@...r.kernel.org,
	linux-kernel@...r.kernel.org, llvm@...ts.linux.dev,
	dri-devel@...ts.freedesktop.org, linux-btrfs@...r.kernel.org,
	linux-hardening@...r.kernel.org
Subject: Re: [PATCH v4 0/2] kbuild: remove gcc's -Wtype-limits

On Thu, Jan 01, 2026 at 04:21:38PM +0100, Vincent Mailhol wrote:
> I often read on the mailing list people saying "who cares about W=2
> builds anyway?". At least I do. Not that I want to fix all of them,
> but on some occasions, such as new driver submissions, I have often
> found a couple valid diagnostics in the W=2 output.
> 
> That said, the annoying thing is that W=2 is heavily polluted by one
> warning: -Wtype-limits. Try a gcc W=2 build on any file and see the
> results for yourself. I suspect this to be the reason why so few
> people are using W=2.
> 
> This series removes gcc's -Wtype-limits in an attempt to make W=2 more
> useful. Those who do not use W=2 can continue to not use it if they
> want. Those who, like me, use it for time to time will get an improved
> experience from the reduced spam.
> 
> Patch #1 deactivates -Wtype-limits. Extra details on statistics, past
> attempts and alternatives are given in the description.
> 
> Patch #2 clean-ups the local Kbuild -Wno-type-limits exceptions.
> 
> Signed-off-by: Vincent Mailhol <mailhol@...nel.org>
> ---
> Changes in v4:
> 
>   - Remove patch #3.
>   - Aside from minor changes in the patch descriptions, this is
>     basially a revert to v1.
> 
> Link to v3: https://lore.kernel.org/r/20251220-remove_wtype-limits-v3-0-24b170af700e@kernel.org

just to prevent confusions:  As Dan silenced the Smatch warning caused
by patch #3 [1] (thanks!), the additional comment patch [2] is obsolete
and v3 of the series is a more complete version than v4.

Kind regards,
Nicolas


[1]: https://github.com/error27/smatch/commit/a7b509b8171b4982b5a2a355f64d083dd76e03f9
[2]: https://lore.kernel.org/linux-kbuild/b6b35138-2c37-4b82-894e-59e897ec7d58@kernel.org/