Re: [PATCH V3 03/13] kprobes: Add symbols for kprobe insn pages

[Jiri Olsa <jolsa@redhat.com>]

On Fri, Feb 28, 2020 at 11:36:00PM +0900, Masami Hiramatsu wrote:
> Hi Adrian,
> 
> On Fri, 28 Feb 2020 15:51:15 +0200
> Adrian Hunter <adrian.hunter@intel.com> wrote:
> 
> > Symbols are needed for tools to describe instruction addresses. Pages
> > allocated for kprobe's purposes need symbols to be created for them.
> > Add such symbols to be visible via /proc/kallsyms.
> 
> I like this idea :)
> 
> > 
> > Note: kprobe insn pages are not used if ftrace is configured. To see the
> > effect of this patch, the kernel must be configured with:
> > 
> > 	# CONFIG_FUNCTION_TRACER is not set
> > 	CONFIG_KPROBES=y
> > 
> > and for optimised kprobes:
> > 
> > 	CONFIG_OPTPROBES=y
> > 
> > Example on x86:
> > 
> > 	# perf probe __schedule
> > 	Added new event:
> > 	  probe:__schedule     (on __schedule)
> > 	# cat /proc/kallsyms | grep '\[kprobe\]'
> > 	ffffffffc0035000 t kprobe_insn_page     [kprobe]
> > 	ffffffffc0054000 t kprobe_optinsn_page  [kprobe]
> 
> Could you make the module name as [kprobes] ?
> BTW, it seems to pretend to be a module, but is there no concern of
> confusing users? Shouldn't it be [*kprobes] so that it is non-exist
> module name?

note we already have bpf symbols as [bpf] module

jirka