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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AF550EB64DC for ; Tue, 11 Jul 2023 13:20:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231631AbjGKNUI (ORCPT ); Tue, 11 Jul 2023 09:20:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44290 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229491AbjGKNUI (ORCPT ); Tue, 11 Jul 2023 09:20:08 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 463C312F; Tue, 11 Jul 2023 06:20:07 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id CF002614DD; Tue, 11 Jul 2023 13:20:06 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 04486C433C8; Tue, 11 Jul 2023 13:20:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1689081606; bh=uOS4JfNufBFC0X+cPyi5FCg/wfbG6rddahqbtej+cxE=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=jtIZOuwVUA6gRzzifFEtONSM8PLmeN4AmB5mo68yP9DT34i44Aa22wqsbGhjsCT8J ZPXjkFA8ZD6l9Km+x9yAaekLi//ruuOFKGDVdIbCKBweHTTwCYQvUSYjSc3Ze3SOfU JqrNdXZoBar9mDR5v8LW5NYZrIMK4nqAQgmlsM/Ruiv9/sPZQJW/jl7HSxT4CCgkfl JeeZjHd9IXp7UyoLjnpIeu7ROxLcYRuqFlc68iyXBPsxa0KrxpxjmjzxHg/i/FpUoN P9PhfeuvKLLlYn0K4D5Q7LdM3eYPjVmCOnq11N0tRkUYRuC/Apwp7IBG5MWp7eiPEa EzK+qIxMkDD6g== Date: Tue, 11 Jul 2023 22:20:00 +0900 From: Masami Hiramatsu (Google) To: Arnaldo Carvalho de Melo Cc: Georg =?UTF-8?B?TcO8bGxlcg==?= , Peter Zijlstra , Ingo Molnar , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Ian Rogers , Adrian Hunter , "Masami Hiramatsu (Google)" , regressions@lists.linux.dev, Arnaldo Carvalho de Melo , linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] perf probe: read DWARF files from the correct CU Message-Id: <20230711222000.d316cf7fd643cb4203ea1204@kernel.org> In-Reply-To: References: <5a00d5a5-7be7-ef8a-4044-9a16249fff25@gmx.net> <20230615200147.664346-3-georgmueller@gmx.net> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.32; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-perf-users@vger.kernel.org On Tue, 11 Jul 2023 09:57:45 -0300 Arnaldo Carvalho de Melo wrote: > Em Thu, Jun 15, 2023 at 10:01:37PM +0200, Georg Müller escreveu: > > After switching from dwarf_decl_file() to die_get_decl_file(), it is not > > possible to add probes for certain functions of certain binaries: > > > > $ perf probe -x /usr/lib/systemd/systemd-logind match_unit_removed > > A function DIE doesn't have decl_line. Maybe broken DWARF? > > A function DIE doesn't have decl_line. Maybe broken DWARF? > > Probe point 'match_unit_removed' not found. > > Error: Failed to add events. > > > > The problem is that die_get_decl_file() uses the wrong CU to search for > > the file. elfutils commit e1db5cdc9f has some good explanation for this: > > > > dwarf_decl_file uses dwarf_attr_integrate to get the DW_AT_decl_file > > attribute. This means the attribute might come from a different DIE > > in a different CU. If so, we need to use the CU associated with the > > attribute, not the original DIE, to resolve the file name. > > > > This patch uses the same source of information as elfutils: use attribute > > DW_AT_decl_file and use this CU to search for the file. > > Thanks, applied to the perf-tools branch, that will be submitted for > Linux v6.5. Thanks Arnaldo and Georg, It sounds perfect reason why that happened. I didn't expect the case that the attribute comes from another CU... Acked-by: Masami Hiramatsu (Google) > > - Arnaldo > > > Fixes: dc9a5d2ccd5c ("perf probe: Fix to get declared file name from clang DWARF5") > > Signed-off-by: Georg Müller > > Link: https://lore.kernel.org/r/5a00d5a5-7be7-ef8a-4044-9a16249fff25@gmx.net/ > > --- > > tools/perf/util/dwarf-aux.c | 4 +++- > > 1 file changed, 3 insertions(+), 1 deletion(-) > > > > diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c > > index b07414409771..137b3ed9897b 100644 > > --- a/tools/perf/util/dwarf-aux.c > > +++ b/tools/perf/util/dwarf-aux.c > > @@ -478,8 +478,10 @@ static const char *die_get_file_name(Dwarf_Die *dw_die, int idx) > > { > > Dwarf_Die cu_die; > > Dwarf_Files *files; > > + Dwarf_Attribute attr_mem; > > > > - if (idx < 0 || !dwarf_diecu(dw_die, &cu_die, NULL, NULL) || > > + if (idx < 0 || !dwarf_attr_integrate(dw_die, DW_AT_decl_file, &attr_mem) || > > + !dwarf_cu_die(attr_mem.cu, &cu_die, NULL, NULL, NULL, NULL, NULL, NULL) || > > dwarf_getsrcfiles(&cu_die, &files, NULL) != 0) > > return NULL; > > > > -- > > 2.41.0 > > > > -- > > - Arnaldo -- Masami Hiramatsu (Google)