Re: [PATCH] crypto: ecc - Unbreak the build on arm with CONFIG_KASAN_STACK=y

Andy Shevchenko
2026-04-08T11:31:26Z

On Wed, Apr 08, 2026 at 08:15:49AM +0200, Lukas Wunner wrote:
> Andrew reports the following build breakage of arm allmodconfig,
> reproducible with gcc 14.2.0 and 15.2.0:
>
> crypto/ecc.c: In function 'ecc_point_mult':
> crypto/ecc.c:1380:1: error: the frame size of 1360 bytes is larger than 1280 bytes [-Werror=frame-larger-than=]
>
> gcc excessively inlines functions called by ecc_point_mult() (without
> there being any explicit inline declarations) and doesn't seem smart
> enough to stay below CONFIG_FRAME_WARN.
>
> clang does not exhibit the issue.
>
> The issue only occurs with CONFIG_KASAN_STACK=y because it enlarges the
> frame size. This has been a controversial topic a couple of times:
>
> https://lore.kernel.org/r/CAK8P3a3_Tdc-XVPXrJ69j3S9048uzmVJGrNcvi0T6yr6OrHkPw@mail.gmail.com/
>
> Prevent gcc from going overboard with inlining to unbreak the build.
> The maximum inline limit to avoid the error is 101. Use 100 to get a
> nice round number per Andrew's preference.

I think this is not the best solution. We still can refactor the code and avoid
being dependant to the (useful) kernel options.

--
With Best Regards,
Andy Shevchenko