Re: [tip: x86/bugs] x86/retpoline: Ensure default return thunk isn't used at runtime

[Ingo Molnar <mingo@xxxxxxxxxx>]

* Borislav Petkov <bp@xxxxxxxxx> wrote:

> diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
> index bb0ab8466b91..e4b2dfbf3de5 100644
> --- a/arch/x86/kernel/cpu/bugs.c
> +++ b/arch/x86/kernel/cpu/bugs.c
> @@ -2849,3 +2849,8 @@ ssize_t cpu_show_gds(struct device *dev, struct device_attribute *attr, char *bu
>  	return cpu_show_common(dev, attr, buf, X86_BUG_GDS);
>  }
>  #endif
> +
> +void check_thunks(void)
> +{
> +	WARN(1, "Unconverted return thunk\n");

If then WARN_ONCE().

Thanks,

	Ingo