Re: [PATCH bpf-next 6/6] bpftool: Show probed function in perf_event link info

From: Yafang Shao <laoar.shao@gmail.com>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org,
	 martin.lau@linux.dev, song@kernel.org, yhs@fb.com,
	john.fastabend@gmail.com,  kpsingh@kernel.org, sdf@google.com,
	haoluo@google.com, jolsa@kernel.org,  quentin@isovalent.com,
	bpf@vger.kernel.org
Subject: Re: [PATCH bpf-next 6/6] bpftool: Show probed function in perf_event link info
Date: Sun, 4 Jun 2023 11:23:29 +0800	[thread overview]
Message-ID: <CALOAHbAwizrH6afP864EfSRNgo61eC0gFnpRaztafXRPcK=BNw@mail.gmail.com> (raw)
In-Reply-To: <20230602203845.iklpi4f6wgdfnbll@MacBook-Pro-8.local>

On Sat, Jun 3, 2023 at 4:38 AM Alexei Starovoitov
<alexei.starovoitov@gmail.com> wrote:
>
> On Fri, Jun 02, 2023 at 08:52:39AM +0000, Yafang Shao wrote:
> > Show the exposed perf_event link info in bpftool. The result as follows,
> >
> > $ bpftool link show
> > 1: perf_event  prog 5
> >         func kernel_clone  addr ffffffffb40bc310  offset 0
> >         bpf_cookie 0
> >         pids trace(9726)
> > $ bpftool link show -j
> > [{"id":1,"type":"perf_event","prog_id":5,"func":"kernel_clone","addr":18446744072435254032,"offset":0,"bpf_cookie":0,"pids":[{"pid":9726,"comm":"trace"}]}]
> >
> > Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
> > ---
> >  tools/bpf/bpftool/link.c | 21 ++++++++++++++++++++-
> >  1 file changed, 20 insertions(+), 1 deletion(-)
> >
> > diff --git a/tools/bpf/bpftool/link.c b/tools/bpf/bpftool/link.c
> > index 3b00c07..045f59f 100644
> > --- a/tools/bpf/bpftool/link.c
> > +++ b/tools/bpf/bpftool/link.c
> > @@ -280,6 +280,12 @@ static int show_link_close_json(int fd, struct bpf_link_info *info)
> >                       kernel_syms_show(addrs, info->kprobe_multi.count, 0);
> >               jsonw_end_array(json_wtr);
> >               break;
> > +     case BPF_LINK_TYPE_PERF_EVENT:
> > +             jsonw_string_field(json_wtr, "func",
> > +                                u64_to_ptr(info->perf_event.name));
> > +             jsonw_uint_field(json_wtr, "addr", info->perf_event.addr);
> > +             jsonw_uint_field(json_wtr, "offset", info->perf_event.offset);
> > +             break;
> >       default:
> >               break;
> >       }
> > @@ -416,7 +422,7 @@ void netfilter_dump_plain(const struct bpf_link_info *info)
> >  static int show_link_close_plain(int fd, struct bpf_link_info *info)
> >  {
> >       struct bpf_prog_info prog_info;
> > -     const char *prog_type_str;
> > +     const char *prog_type_str, *buf;
> >       int err;
> >
> >       show_link_header_plain(info);
> > @@ -472,6 +478,12 @@ static int show_link_close_plain(int fd, struct bpf_link_info *info)
> >               addrs = (const __u64 *)u64_to_ptr(info->kprobe_multi.addrs);
> >               kernel_syms_show(addrs, cnt, indent);
> >               break;
> > +     case BPF_LINK_TYPE_PERF_EVENT:
> > +             buf = (const char *)u64_to_ptr(info->perf_event.name);
> > +             if (buf[0] != '\0' || info->perf_event.addr)
> > +                     printf("\n\tfunc %s  addr %llx  offset %d  ", buf,
> > +                            info->perf_event.addr, info->perf_event.offset);
>
> Let's print the name here as well?

Sure, I will use 'name' instead.

-- 
Regards
Yafang