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=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 8C049C43460 for ; Mon, 3 May 2021 16:51:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5711C61165 for ; Mon, 3 May 2021 16:51:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233738AbhECQwH (ORCPT ); Mon, 3 May 2021 12:52:07 -0400 Received: from mx2.suse.de ([195.135.220.15]:37060 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233393AbhECQrw (ORCPT ); Mon, 3 May 2021 12:47:52 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id BF7A4AF2C; Mon, 3 May 2021 16:46:57 +0000 (UTC) Date: Mon, 3 May 2021 18:46:56 +0200 From: Michal =?iso-8859-1?Q?Such=E1nek?= To: Jiri Olsa Cc: Jiri Slaby , Yonghong Song , linux-kernel@vger.kernel.org, Martin KaFai Lau , "David S. Miller" , Hideaki YOSHIFUJI , David Ahern , Jakub Kicinski , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Song Liu , John Fastabend , KP Singh , netdev@vger.kernel.org, bpf@vger.kernel.org, Jiri Olsa , Jesper Dangaard Brouer , dwarves@vger.kernel.org, Arnaldo Carvalho de Melo Subject: Re: linux-next failing build due to missing cubictcp_state symbol Message-ID: <20210503164656.GO6564@kitsune.suse.cz> References: <49f84147-bf32-dc59-48e0-f89241cf6264@fb.com> <20210427121237.GK6564@kitsune.suse.cz> <20210430174723.GP15381@kitsune.suse.cz> <3d148516-0472-8f0a-085b-94d68c5cc0d5@suse.com> <6c14f3c8-7474-9f3f-b4a6-2966cb19e1ed@kernel.org> <4e051459-8532-7b61-c815-f3435767f8a0@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.11.3 (2019-02-01) Precedence: bulk List-ID: X-Mailing-List: dwarves@vger.kernel.org On Mon, May 03, 2021 at 12:08:02PM +0200, Jiri Olsa wrote: > On Mon, May 03, 2021 at 10:59:44AM +0200, Jiri Slaby wrote: > > CCing pahole people. > > > > On 03. 05. 21, 9:59, Jiri Slaby wrote: > > > On 03. 05. 21, 8:11, Jiri Slaby wrote: > > > > > > > > > looks like vfs_truncate did not get into BTF data, > > > > > > > > > I'll try to reproduce > > > > > > > > > > _None_ of the functions are generated by pahole -J from > > > > > debuginfo on ppc64. debuginfo appears to be correct. Neither > > > > > pahole -J fs/open.o works correctly. collect_functions in > > > > > dwarves seems to be defunct on ppc64... "functions" array is > > > > > bogus (so find_function -- the bsearch -- fails). > > > > > > > > It's not that bogus. I forgot an asterisk: > > > > > #0  find_function (btfe=0x100269f80, name=0x10024631c > > > > > "stream_open") at > > > > > /usr/src/debug/dwarves-1.21-1.1.ppc64/btf_encoder.c:350 > > > > > (gdb) p (*functions)@84 > > > > > $5 = {{name = 0x7ffff68e0922 ".__se_compat_sys_ftruncate", addr > > > > > = 75232, size = 72, sh_addr = 65536, generated = false}, { > > > > >     name = 0x7ffff68e019e ".__se_compat_sys_open", addr = 80592, > > > > > size = 216, sh_addr = 65536, generated = false}, { > > > > >     name = 0x7ffff68e0076 ".__se_compat_sys_openat", addr = > > > > > 80816, size = 232, sh_addr = 65536, generated = false}, { > > > > >     name = 0x7ffff68e0908 ".__se_compat_sys_truncate", addr = > > > > > 74304, size = 100, sh_addr = 65536, generated = false}, { > > > > ... > > > > >     name = 0x7ffff68e0808 ".stream_open", addr = 65824, size = > > > > > 72, sh_addr = 65536, generated = false}, { > > > > ... > > > > >     name = 0x7ffff68e0751 ".vfs_truncate", addr = 73392, size = > > > > > 544, sh_addr = 65536, generated = false}} > > > > > > > > The dot makes the difference, of course. The question is why is it > > > > there? I keep looking into it. Only if someone has an immediate > > > > idea... > > > > > > Well, .vfs_truncate is in .text (and contains an ._mcount call). And > > > vfs_truncate is in .opd (w/o an ._mcount call). Since setup_functions > > > excludes all functions without the ._mcount call, is_ftrace_func later > > > returns false for such functions and they are filtered before the BTF > > > processing. > > > > > > Technically, get_vmlinux_addrs looks at a list of functions between > > > __start_mcount_loc and __stop_mcount_loc and considers only the listed. > > > > > > I don't know what the correct fix is (exclude .opd functions from the > > > filter?). Neither why cross compiler doesn't fail, nor why ebi v2 avoids > > > this too. > > > > Attaching a patch for pahole which fixes the issue, but I have no idea > > whether it is the right fix at all. > > hi, > we're considering to disable ftrace filter completely, > I guess that would solve this issue for ppc as well > > https://lore.kernel.org/bpf/20210501001653.x3b4rk4vk4iqv3n7@kafai-mbp.dhcp.thefacebook.com/ > Just disabling the ftrace filter in pahole does not seem to fix it. Is there some other place where it should be disabled? Thanks Michal