Re: [PATCH v3 01/10] x86/cfi: Add warn option

[Peter Zijlstra <peterz@infradead.org>]

On Wed, Feb 19, 2025 at 09:50:54AM -0800, Kees Cook wrote:
> On Wed, Feb 19, 2025 at 05:21:08PM +0100, Peter Zijlstra wrote:
> > Rebuilding with CFI_PERMISSIVE toggled is such a pain, esp. since
> > clang is so slow.
> 
> This seems too complex; report_cfi_failure() already has the fail/warn
> logic test. I would have expected cfi_warn to take CONFIG_CFI_PERMISSIVE
> as a default instead, like:
> 
> +bool cfi_warn __ro_after_init = IS_ENABLED(CONFIG_CFI_PERMISSIVE);

In kernel/cfi.c, yes that works.

I somehow got stuck with having cfi_warn in arch/x86 and then not being
able to use it in generic code. Been too busy to debug all the fun fails
to realize I could simply stick the variable in generic code.