Re: [PATCH] perf-probe: Accept the instance number of kretprobe event

From: Masami Hiramatsu <mhiramat@kernel.org>
To: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: yshuiv7@gmail.com, Jiri Olsa <jolsa@redhat.com>,
	Namhyung Kim <namhyung@kernel.org>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] perf-probe: Accept the instance number of kretprobe event
Date: Thu, 7 May 2020 17:44:16 +0900	[thread overview]
Message-ID: <20200507174416.185e9aead7072d478d3abd5f@kernel.org> (raw)
In-Reply-To: <20200506164131.GB22183@kernel.org>

On Wed, 6 May 2020 13:41:31 -0300
Arnaldo Carvalho de Melo <acme@kernel.org> wrote:

> Em Wed, May 06, 2020 at 01:17:23PM -0300, Arnaldo Carvalho de Melo escreveu:
> > Em Wed, May 06, 2020 at 11:29:12PM +0900, Masami Hiramatsu escreveu:
> > > Since the commit 6a13a0d7b4d1 ("ftrace/kprobe: Show the
> > > maxactive number on kprobe_events") introduced to show the
> > > instance number of kretprobe events, the length of the 1st
> > > format of the kprobe event will not 1, but it can be longer.
> > > This caused a parser error in perf-probe.
> > 
> > Thanks for the quick fix!
> > 
> > I'll add this right after the Fixes tag:
> > 
> > Reported-by: yshuiv7@gmail.com
> > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=207587
> 
> Sorry, I didn't notice you added it as a Link: :-)
> 
> > Ok?

Yes, I missed the yshuiv's mail so missed it. please add it :)

Thank you,

> > 
> > yshuiv, can I have your name to add to that Reported-by tag? And if you
> > test it, please, I can add a Tested-by: tag as well, credits where
> > credits are due!
> > 
> > Thanks!
> > 
> > - Arnaldo
> >  
> > > Skip the length check the 1st format of the kprobe event
> > > to accept this instance number.
> > > 
> > > Without this fix:
> > > 
> > >   # perf probe -a vfs_read%return
> > >   Added new event:
> > >     probe:vfs_read__return (on vfs_read%return)
> > > 
> > >   You can now use it in all perf tools, such as:
> > > 
> > >   	perf record -e probe:vfs_read__return -aR sleep 1
> > > 
> > >   # perf probe -l
> > >   Semantic error :Failed to parse event name: r16:probe/vfs_read__return
> > >     Error: Failed to show event list.
> > > 
> > > And with this fixes:
> > > 
> > >   # perf probe -a vfs_read%return
> > >   ...
> > >   # perf probe -l
> > >     probe:vfs_read__return (on vfs_read%return)
> > > 
> > > 
> > > Fixes: 6a13a0d7b4d1 ("ftrace/kprobe: Show the maxactive number on kprobe_events")
> > > Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
> > > Cc: stable@vger.kernel.org
> > > Link: https://bugzilla.kernel.org/show_bug.cgi?id=207587
> > > ---
> > >  tools/perf/util/probe-event.c |    3 +--
> > >  1 file changed, 1 insertion(+), 2 deletions(-)
> > > 
> > > diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
> > > index eea132f512b0..c6bcf5709564 100644
> > > --- a/tools/perf/util/probe-event.c
> > > +++ b/tools/perf/util/probe-event.c
> > > @@ -1765,8 +1765,7 @@ int parse_probe_trace_command(const char *cmd, struct probe_trace_event *tev)
> > >  	fmt1_str = strtok_r(argv0_str, ":", &fmt);
> > >  	fmt2_str = strtok_r(NULL, "/", &fmt);
> > >  	fmt3_str = strtok_r(NULL, " \t", &fmt);
> > > -	if (fmt1_str == NULL || strlen(fmt1_str) != 1 || fmt2_str == NULL
> > > -	    || fmt3_str == NULL) {
> > > +	if (fmt1_str == NULL || fmt2_str == NULL || fmt3_str == NULL) {
> > >  		semantic_error("Failed to parse event name: %s\n", argv[0]);
> > >  		ret = -EINVAL;
> > >  		goto out;
> > > 
> > 
> > -- 
> > 
> > - Arnaldo
> 
> -- 
> 
> - Arnaldo

-- 
Masami Hiramatsu <mhiramat@kernel.org>