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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 829CCC433FE for ; Tue, 28 Sep 2021 20:47:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6BF146108E for ; Tue, 28 Sep 2021 20:47:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242786AbhI1UtP (ORCPT ); Tue, 28 Sep 2021 16:49:15 -0400 Received: from wildebeest.demon.nl ([212.238.236.112]:60770 "EHLO gnu.wildebeest.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242572AbhI1UtL (ORCPT ); Tue, 28 Sep 2021 16:49:11 -0400 X-Greylist: delayed 503 seconds by postgrey-1.27 at vger.kernel.org; Tue, 28 Sep 2021 16:49:11 EDT Received: from reform (deer0x0a.wildebeest.org [172.31.17.140]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by gnu.wildebeest.org (Postfix) with ESMTPSA id 5332F3000A0A; Tue, 28 Sep 2021 22:39:06 +0200 (CEST) Received: by reform (Postfix, from userid 1000) id D69F92E80D92; Tue, 28 Sep 2021 22:39:05 +0200 (CEST) Date: Tue, 28 Sep 2021 22:39:05 +0200 From: Mark Wielaard To: Jiri Olsa Cc: Arnaldo Carvalho de Melo , Sukadev Bhattiprolu , lkml , Peter Zijlstra , Ingo Molnar , Mark Rutland , Namhyung Kim , Alexander Shishkin , Michael Petlan , Ian Rogers , linux-perf-users@vger.kernel.org Subject: Re: [PATCH] perf tools: Fix compilation on powerpc Message-ID: References: <20210928195253.1267023-1-jolsa@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20210928195253.1267023-1-jolsa@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On Tue, Sep 28, 2021 at 09:52:53PM +0200, Jiri Olsa wrote: > Got following build fail on powerpc: > > CC arch/powerpc/util/skip-callchain-idx.o > In function ‘check_return_reg’, > inlined from ‘check_return_addr’ at arch/powerpc/util/skip-callchain-idx.c:213:7, > inlined from ‘arch_skip_callchain_idx’ at arch/powerpc/util/skip-callchain-idx.c:265:7: > arch/powerpc/util/skip-callchain-idx.c:54:18: error: ‘dwarf_frame_register’ accessing 96 bytes \ > in a region of size 64 [-Werror=stringop-overflow=] > 54 | result = dwarf_frame_register(frame, ra_regno, ops_mem, &ops, &nops); > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > arch/powerpc/util/skip-callchain-idx.c: In function ‘arch_skip_callchain_idx’: > arch/powerpc/util/skip-callchain-idx.c:54:18: note: referencing argument 3 of type ‘Dwarf_Op *’ > In file included from /usr/include/elfutils/libdwfl.h:32, > from arch/powerpc/util/skip-callchain-idx.c:10: > /usr/include/elfutils/libdw.h:1069:12: note: in a call to function ‘dwarf_frame_register’ > 1069 | extern int dwarf_frame_register (Dwarf_Frame *frame, int regno, > | ^~~~~~~~~~~~~~~~~~~~ > cc1: all warnings being treated as errors > > The dwarf_frame_register args changed with [1], > Updating ops_mem accordingly. > > [1] https://sourceware.org/git/?p=elfutils.git;a=commit;h=5621fe5443da23112170235dd5cac161e5c75e65 The warning (new with GCC11) and the fix are correct. The code probably worked fine before because the next var on the stack was the dummy Dwarf_Op which would have been as if the ops_mem[2] was actually ops_mem[3] already. You don't need the dummy var now and Dwarf_Op *ops doesn't need to be initialized (the dwarf_frame_register will initialize it). Note that [1] didn't change the args of the dwarf_frame_register, but did fix a similar bug in one of the elfutils own tests (and updated the comment on the function to hopefully be more clear). Cheers, Mark > Cc: Mark Wielaard > Cc: Sukadev Bhattiprolu > Signed-off-by: Jiri Olsa > --- > tools/perf/arch/powerpc/util/skip-callchain-idx.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/tools/perf/arch/powerpc/util/skip-callchain-idx.c b/tools/perf/arch/powerpc/util/skip-callchain-idx.c > index 3018a054526a..20cd6244863b 100644 > --- a/tools/perf/arch/powerpc/util/skip-callchain-idx.c > +++ b/tools/perf/arch/powerpc/util/skip-callchain-idx.c > @@ -45,7 +45,7 @@ static const Dwfl_Callbacks offline_callbacks = { > */ > static int check_return_reg(int ra_regno, Dwarf_Frame *frame) > { > - Dwarf_Op ops_mem[2]; > + Dwarf_Op ops_mem[3]; > Dwarf_Op dummy; > Dwarf_Op *ops = &dummy; > size_t nops; > -- > 2.31.1 >