linux-kernel - Re: [PATCH] perf utils: silent "Couldn't synthesize bpf events" warning for EPERM

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Message-ID: <20190204203018.GD4794@krava>
Date:   Mon, 4 Feb 2019 21:30:18 +0100
From:   Jiri Olsa <jolsa@...hat.com>
To:     Song Liu <songliubraving@...com>
Cc:     lkml <linux-kernel@...r.kernel.org>,
        Kernel Team <Kernel-team@...com>,
        Arnaldo Carvalho de Melo <acme@...hat.com>,
        David Carrillo Cisneros <davidca@...com>
Subject: Re: [PATCH] perf utils: silent "Couldn't synthesize bpf events"
 warning for EPERM

On Mon, Feb 04, 2019 at 07:33:06PM +0000, Song Liu wrote:
> 
> 
> > On Feb 4, 2019, at 11:31 AM, Song Liu <songliubraving@...com> wrote:
> > 
> > Synthesizing BPF events is only supported for root. Silent warning msg
> > when non-root user runs perf-record.

great, it was annoying ;-)

Tested-by: Jiri Olsa <jolsa@...nel.org>

thanks,
jirka

> > 
> > Cc: Arnaldo Carvalho de Melo <acme@...hat.com>
> > Cc: Jiri Olsa <jolsa@...hat.com>
> > Reported-by: David Carrillo-Cisneros <davidca@...com>
> > Tested-by: David Carrillo-Cisneros <davidca@...com>
> > Signed-off-by: Song Liu <songliubraving@...com>
> > ---
> > tools/perf/util/bpf-event.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/tools/perf/util/bpf-event.c b/tools/perf/util/bpf-event.c
> > index 796ef793f4ce..62dda96b0096 100644
> > --- a/tools/perf/util/bpf-event.c
> > +++ b/tools/perf/util/bpf-event.c
> > @@ -236,8 +236,8 @@ int perf_event__synthesize_bpf_events(struct perf_tool *tool,
> > 			pr_debug("%s: can't get next program: %s%s",
> > 				 __func__, strerror(errno),
> > 				 errno == EINVAL ? " -- kernel too old?" : "");
> > -			/* don't report error on old kernel */
> > -			err = (errno == EINVAL) ? 0 : -1;
> > +			/* don't report error on old kernel or EPERM  */
> > +			err = (errno == EINVAL || errno == EPERM) ? 0 : -1;
> > 			break;
> > 		}
> > 		fd = bpf_prog_get_fd_by_id(id);
> > -- 
> > 2.17.1
> > 
> 
> CC David.