Re: [PATCH v3 2/8] fprobe: Use fprobe_regs in fprobe entry handler

[Florent Revest <revest@xxxxxxxxxxxx>]

On Sat, Aug 12, 2023 at 7:37 AM Masami Hiramatsu (Google)
<mhiramat@xxxxxxxxxx> wrote:
> --- a/kernel/trace/bpf_trace.c
> +++ b/kernel/trace/bpf_trace.c
> @@ -2467,7 +2467,7 @@ static int __init bpf_event_init(void)
>  fs_initcall(bpf_event_init);
>  #endif /* CONFIG_MODULES */
>
> -#ifdef CONFIG_FPROBE
> +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS

Shouldn't this be #if defined(CONFIG_FPROBE) &&
defined(CONFIG_DYNAMIC_FTRACE_WITH_REGS) ?

I believe one could build a kernel with FTRACE_WITH_REGS and without
FPROBE and then this code would have undefined references to fprobe
functions, wouldn't it ?

And then patch 7 should be "Enable kprobe_multi feature even if
FTRACE_WITH_REGS is disabled"