Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751186AbbDZA4O (ORCPT ); Sat, 25 Apr 2015 20:56:14 -0400 Received: from mail9.hitachi.co.jp ([133.145.228.44]:42279 "EHLO mail9.hitachi.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750958AbbDZA4N (ORCPT ); Sat, 25 Apr 2015 20:56:13 -0400 Message-ID: <553C37A6.3090206@hitachi.com> Date: Sun, 26 Apr 2015 09:56:06 +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: He Kuang CC: acme@kernel.org, a.p.zijlstra@chello.nl, mingo@redhat.com, paulus@samba.org, wangnan0@huawei.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH] perf probe: Fix bug in perf probe with global variables References: <1429949338-18678-1-git-send-email-hekuang@huawei.com> In-Reply-To: <1429949338-18678-1-git-send-email-hekuang@huawei.com> Content-Type: text/plain; charset=ISO-2022-JP Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2782 Lines: 78 (2015/04/25 17:08), He Kuang wrote: > There are missing curly braces which causes find_variable() return wrong > value when probing with global variables. > > This problem can be reproduced as following: > > $ perf probe -v --add='generic_perform_write global_variable_for_test' > ... > Try to find probe point from debuginfo. > Probe point found: generic_perform_write+0 > Searching 'global_variable_for_test' variable in context. > An error occurred in debuginfo analysis (-2). > Error: Failed to add events. Reason: No such file or directory (Code: -2) > > After this patch: > > $ perf probe -v --add='generic_perform_write global_variable_for_test' > ... > Converting variable global_variable_for_test into trace event. > global_variable_for_test type is int. > Found 1 probe_trace_events. > Opening /sys/kernel/debug/tracing/kprobe_events write=1 > Added new event: > Writing event: p:probe/generic_perform_write _stext+1237464 > global_variable_for_test=@global_variable_for_test+0:s32 > probe:generic_perform_write (on generic_perform_write with > global_variable_for_test) > > You can now use it in all perf tools, such as: > > perf record -e probe:generic_perform_write -aR sleep 1 Oops, that's my fault! :( Acked-by: Masami Hiramatsu Thank you!! > > Signed-off-by: He Kuang > --- > tools/perf/util/probe-finder.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c > index 44554c3..1c3cc07 100644 > --- a/tools/perf/util/probe-finder.c > +++ b/tools/perf/util/probe-finder.c > @@ -578,10 +578,12 @@ static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf) > /* Search child die for local variables and parameters. */ > if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) { > /* Search again in global variables */ > - if (!die_find_variable_at(&pf->cu_die, pf->pvar->var, 0, &vr_die)) > + if (!die_find_variable_at(&pf->cu_die, pf->pvar->var, > + 0, &vr_die)) { > pr_warning("Failed to find '%s' in this function.\n", > pf->pvar->var); > ret = -ENOENT; > + } > } > if (ret >= 0) > ret = convert_variable(&vr_die, pf); > -- Masami HIRAMATSU Linux Technology Research Center, System Productivity Research Dept. Center for Technology Innovation - Systems Engineering Hitachi, Ltd., Research & Development Group 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/