Re: [PATCH v19 12/19] fprobe: Rewrite fprobe on function-graph tracer

Masami Hiramatsu
2024-12-05T23:10:01Z

On Thu, 5 Dec 2024 13:34:24 -0500
Steven Rostedt <rostedt@goodmis.org> wrote:

> On Mon, 11 Nov 2024 00:51:09 +0900
> "Masami Hiramatsu (Google)" <mhiramat@kernel.org> wrote:
>
> > diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
> > index 2fc55a1a88aa..91a6382c04bd 100644
> > --- a/kernel/trace/Kconfig
> > +++ b/kernel/trace/Kconfig
> > @@ -307,12 +307,10 @@ config DYNAMIC_FTRACE_WITH_ARGS
> >
> > config FPROBE
> > bool "Kernel Function Probe (fprobe)"
> > - depends on FUNCTION_TRACER
> > - depends on DYNAMIC_FTRACE_WITH_REGS || DYNAMIC_FTRACE_WITH_ARGS
> > - depends on HAVE_FTRACE_REGS_HAVING_PT_REGS || !HAVE_DYNAMIC_FTRACE_WITH_ARGS
> > - depends on HAVE_RETHOOK
> > - select RETHOOK
> > - default n
> > + depends on HAVE_FUNCTION_GRAPH_FREGS && HAVE_FTRACE_GRAPH_FUNC
> > + depends on DYNAMIC_FTRACE_WITH_ARGS
> > + select FUNCTION_GRAPH_TRACER
> > + default y
>
> Please remove the "default y". This will select function graph tracer and
> will not let you to disable it without disabling this.

Good catch! I forgot about the combination's side effect.

>
> If you really want to tick off Linus, then make an option that selects other
> options "default y" ;-)

Oh, no, I don't want it.

>
> Can you rebase the series off of v6.13-rc1? There's a minor conflict with
> the riscv Kconfig.

OK, let me update.

Thank you!

>
> -- Steve
>
>
> > help
> > This option enables kernel function probe (fprobe) based on ftrace.
> > The fprobe is similar to kprobes, but probes only for kernel function

--
Masami Hiramatsu (Google) <mhiramat@kernel.org>