Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752391AbbB1DVO (ORCPT ); Fri, 27 Feb 2015 22:21:14 -0500 Received: from mail7.hitachi.co.jp ([133.145.228.42]:33107 "EHLO mail7.hitachi.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750799AbbB1DVN (ORCPT ); Fri, 27 Feb 2015 22:21:13 -0500 Message-ID: <54F13421.5010404@hitachi.com> Date: Sat, 28 Feb 2015 12:21:05 +0900 From: Masami Hiramatsu Organization: Hitachi, Ltd., Japan User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:13.0) Gecko/20120614 Thunderbird/13.0.1 MIME-Version: 1.0 To: Arnaldo Carvalho de Melo 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 References: <20150226144042.GB1079@kernel.org> <20150228025329.32106.70581.stgit@localhost.localdomain> In-Reply-To: <20150228025329.32106.70581.stgit@localhost.localdomain> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3002 Lines: 92 (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, > 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/