Re: [RFC][PATCH] x86,ibt: Use UDB instead of 0xEA

[Peter Zijlstra]

On Thu, Aug 14, 2025 at 01:17:33PM +0200, Peter Zijlstra wrote:
> diff --git a/arch/x86/kernel/cet.c b/arch/x86/kernel/cet.c
> index 99444409c026..59f8bf022ec5 100644
> --- a/arch/x86/kernel/cet.c
> +++ b/arch/x86/kernel/cet.c
> @@ -123,7 +123,7 @@ static void do_kernel_cp_fault(struct pt_regs *regs, unsigned long error_code)
>  		return;
>  	}
>  
> -	pr_err("Missing ENDBR: %pS\n", (void *)instruction_pointer(regs));
> +	early_printk("Missing ENDBR: %pS\n", (void *)instruction_pointer(regs));
>  	if (!ibt_fatal) {
>  		printk(KERN_DEFAULT CUT_HERE);
>  		__warn(__FILE__, __LINE__, (void *)regs->ip, TAINT_WARN, regs, NULL);

Obviously this is debugging remnant and will go away.