Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752411AbbB1UqB (ORCPT ); Sat, 28 Feb 2015 15:46:01 -0500 Received: from mail.kernel.org ([198.145.29.136]:38813 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751389AbbB1Up7 (ORCPT ); Sat, 28 Feb 2015 15:45:59 -0500 Date: Sat, 28 Feb 2015 17:45:54 -0300 From: Arnaldo Carvalho de Melo To: Masami Hiramatsu Cc: Jiri Olsa , Linux Kernel Mailing List , David Ahern Subject: Re: [PATCH perf/core ] perf-probe: Warn if given uprobe event accesses memory on older kernel Message-ID: <20150228204554.GF28401@kernel.org> References: <20150226144042.GB1079@kernel.org> <20150228025329.32106.70581.stgit@localhost.localdomain> <54F13421.5010404@hitachi.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <54F13421.5010404@hitachi.com> X-Url: http://acmel.wordpress.com User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3359 Lines: 101 Em Sat, Feb 28, 2015 at 12:21:05PM +0900, Masami Hiramatsu escreveu: > (2015/02/28 11:53), Masami Hiramatsu wrote: > > Warn if given uprobe event accesses memory on older kernel. > > Until 3.14, uprobe event only supports accessing registers > > so this warns to upgrade kernel if uprobe-event returns > > -EINVAL and an argument of the event accesses memory ($stack, > > @+offset, and +|-offs() symtax). > > > > With this patch (on 3.10.0-123.13.2.el7.x86_64); > > ----- > > # ./perf probe -x ./perf warn_uprobe_event_compat stack=-0\(%sp\) > > Added new event: > > Failed to write event: Invalid argument > > Please upgrade your kernel to at least 3.14 to have access to feature -0(%sp) > > Error: Failed to add events. > > ----- > > > > Oops, > > Suggested-by: Arnaldo Carvalho de Melo :-) Thanks for considering my suggestion and coming up with a patch so quickly! I'll test it and merge, - Arnaldo > Thanks, > > > Signed-off-by: Masami Hiramatsu > > --- > > tools/perf/util/probe-event.c | 23 +++++++++++++++++++++++ > > 1 file changed, 23 insertions(+) > > > > diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c > > index 7c0e765..1c570c2fa7 100644 > > --- a/tools/perf/util/probe-event.c > > +++ b/tools/perf/util/probe-event.c > > @@ -2199,6 +2199,27 @@ static int get_new_event_name(char *buf, size_t len, const char *base, > > return ret; > > } > > > > +/* Warn if the current kernel's uprobe implementation is old */ > > +static void warn_uprobe_event_compat(struct probe_trace_event *tev) > > +{ > > + int i; > > + char *buf = synthesize_probe_trace_command(tev); > > + > > + /* Old uprobe event doesn't support memory dereference */ > > + if (!tev->uprobes || tev->nargs == 0 || !buf) > > + goto out; > > + > > + for (i = 0; i < tev->nargs; i++) > > + if (strglobmatch(tev->args[i].value, "[$@+-]*")) { > > + pr_warning("Please upgrade your kernel to at least " > > + "3.14 to have access to feature %s\n", > > + tev->args[i].value); > > + break; > > + } > > +out: > > + free(buf); > > +} > > + > > static int __add_probe_trace_events(struct perf_probe_event *pev, > > struct probe_trace_event *tevs, > > int ntevs, bool allow_suffix) > > @@ -2295,6 +2316,8 @@ static int __add_probe_trace_events(struct perf_probe_event *pev, > > */ > > allow_suffix = true; > > } > > + if (ret == -EINVAL && pev->uprobes) > > + warn_uprobe_event_compat(tev); > > > > /* Note that it is possible to skip all events because of blacklist */ > > if (ret >= 0 && tev->event) { > > > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > > the body of a message to majordomo@vger.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > Please read the FAQ at http://www.tux.org/lkml/ > > > > > > > > > -- > Masami HIRAMATSU > Software Platform Research Dept. Linux Technology Research Center > Hitachi, Ltd., Yokohama Research Laboratory > E-mail: masami.hiramatsu.pt@hitachi.com > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/