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

[Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>]

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?
> 
> 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