Re: [RFC PATCH v2 1/6] fprobe: Use fprobe_regs in fprobe entry handler

[Steven Rostedt]

On Thu, 10 Aug 2023 07:13:30 +0900
Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx> wrote:

> > 
> > I hope that makes my thoughts clearer? It's a hairy topic ahah  
> 
> Ah, I see your point.
> 
> static void fprobe_init(struct fprobe *fp)
> {
>         fp->nmissed = 0;
>         if (fprobe_shared_with_kprobes(fp))
>                 fp->ops.func = fprobe_kprobe_handler;
>         else
>                 fp->ops.func = fprobe_handler;
>         fp->ops.flags |= FTRACE_OPS_FL_SAVE_REGS; <---- This flag!
> }
> 
> So it should be FTRACE_OPS_FL_ARGS. Let me fix that.

Yes, this was the concern that I was bringing up, where I did not see an
advantage of fprobes over kprobes using ftrace, because they both were
saving all registers.

-- Steve