From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D7EA4C35242 for ; Sat, 8 Feb 2020 18:36:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BC4C520733 for ; Sat, 8 Feb 2020 18:36:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728426AbgBHSgk (ORCPT ); Sat, 8 Feb 2020 13:36:40 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:33882 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727790AbgBHS3k (ORCPT ); Sat, 8 Feb 2020 13:29:40 -0500 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1j0UrI-0003dc-0U; Sat, 08 Feb 2020 18:29:36 +0000 Received: from ben by deadeye with local (Exim 4.93) (envelope-from ) id 1j0UrH-000COI-PP; Sat, 08 Feb 2020 18:29:35 +0000 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "Jiri Olsa" , "Masami Hiramatsu" , "Arnaldo Carvalho de Melo" , "Namhyung Kim" , "Arnaldo Carvalho de Melo" Date: Sat, 08 Feb 2020 18:20:05 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 066/148] perf probe: Fix to probe a function which has no entry pc In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.82-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Masami Hiramatsu commit 5d16dbcc311d91267ddb45c6da4f187be320ecee upstream. Fix 'perf probe' to probe a function which has no entry pc or low pc but only has ranges attribute. probe_point_search_cb() uses dwarf_entrypc() to get the probe address, but that doesn't work for the function DIE which has only ranges attribute. Use die_entrypc() instead. Without this fix: # perf probe -k ../build-x86_64/vmlinux -D clear_tasks_mm_cpumask:0 Probe point 'clear_tasks_mm_cpumask' not found. Error: Failed to add events. With this: # perf probe -k ../build-x86_64/vmlinux -D clear_tasks_mm_cpumask:0 p:probe/clear_tasks_mm_cpumask clear_tasks_mm_cpumask+0 Committer testing: Before: [root@quaco ~]# perf probe clear_tasks_mm_cpumask:0 Probe point 'clear_tasks_mm_cpumask' not found. Error: Failed to add events. [root@quaco ~]# After: [root@quaco ~]# perf probe clear_tasks_mm_cpumask:0 Added new event: probe:clear_tasks_mm_cpumask (on clear_tasks_mm_cpumask) You can now use it in all perf tools, such as: perf record -e probe:clear_tasks_mm_cpumask -aR sleep 1 [root@quaco ~]# Using it with 'perf trace': [root@quaco ~]# perf trace -e probe:clear_tasks_mm_cpumask Doesn't seem to be used in x86_64: $ find . -name "*.c" | xargs grep clear_tasks_mm_cpumask ./kernel/cpu.c: * clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU ./kernel/cpu.c:void clear_tasks_mm_cpumask(int cpu) ./arch/xtensa/kernel/smp.c: clear_tasks_mm_cpumask(cpu); ./arch/csky/kernel/smp.c: clear_tasks_mm_cpumask(cpu); ./arch/sh/kernel/smp.c: clear_tasks_mm_cpumask(cpu); ./arch/arm/kernel/smp.c: clear_tasks_mm_cpumask(cpu); ./arch/powerpc/mm/nohash/mmu_context.c: clear_tasks_mm_cpumask(cpu); $ find . -name "*.h" | xargs grep clear_tasks_mm_cpumask ./include/linux/cpu.h:void clear_tasks_mm_cpumask(int cpu); $ find . -name "*.S" | xargs grep clear_tasks_mm_cpumask $ Fixes: e1ecbbc3fa83 ("perf probe: Fix to handle optimized not-inlined functions") Reported-by: Arnaldo Carvalho de Melo Tested-by: Arnaldo Carvalho de Melo Signed-off-by: Masami Hiramatsu Cc: Jiri Olsa Cc: Namhyung Kim Link: http://lore.kernel.org/lkml/157199319438.8075.4695576954550638618.stgit@devnote2 Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Ben Hutchings --- tools/perf/util/probe-finder.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/tools/perf/util/probe-finder.c +++ b/tools/perf/util/probe-finder.c @@ -908,7 +908,7 @@ static int probe_point_search_cb(Dwarf_D param->retval = find_probe_point_by_line(pf); } else if (die_is_func_instance(sp_die)) { /* Instances always have the entry address */ - dwarf_entrypc(sp_die, &pf->addr); + die_entrypc(sp_die, &pf->addr); /* But in some case the entry address is 0 */ if (pf->addr == 0) { pr_debug("%s has no entry PC. Skipped\n",