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[23.128.96.18]) by mx.google.com with ESMTP id s24si9836295ejr.705.2021.05.03.03.27.08; Mon, 03 May 2021 03:27:32 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=YGTcRvws; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233297AbhECKJQ (ORCPT + 99 others); Mon, 3 May 2021 06:09:16 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:40060 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233296AbhECKJK (ORCPT ); Mon, 3 May 2021 06:09:10 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1620036496; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=QM7LX30zixFvAJA+LWpBmSBCqZL3DHOeqR3gSdt7mUE=; b=YGTcRvwsi8LSqWLfVmLIrHtHL8KbhSTwfWavCoJTBXiZSJanvFxU80IxY1n2lnEbkV/v2q nP5GAgA5aAxkwnjqD29DXS1SbV9tb45fdiwzO8UhFt979l+JvFStxqMRaip2oreGmIgJlV LeuO8wnepuKZPP23bam8p9oqxKBqhLY= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-272-MOHmxVoAPHOVkocEE9n3hg-1; Mon, 03 May 2021 06:08:13 -0400 X-MC-Unique: MOHmxVoAPHOVkocEE9n3hg-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 66FCD107ACC7; Mon, 3 May 2021 10:08:11 +0000 (UTC) Received: from krava (unknown [10.40.195.47]) by smtp.corp.redhat.com (Postfix) with ESMTP id 48D291001B2C; Mon, 3 May 2021 10:08:03 +0000 (UTC) Date: Mon, 3 May 2021 12:08:02 +0200 From: Jiri Olsa To: Jiri Slaby Cc: Michal =?iso-8859-1?Q?Such=E1nek?= , 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: References: <20210426121401.GO15381@kitsune.suse.cz> <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: X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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/ jirka > > > regards,-- > js > suse labs > From: Jiri Slaby > Subject: ppc64: .opd section fix > Patch-mainline: submitted 2021/05/03 > > Functions in the .opd section should be considered valid too. Otherwise, > pahole cannot produce a .BTF section from vmlinux and kernel build > fails on ppc64. > --- > btf_encoder.c | 18 +++++++++++++++++- > 1 file changed, 17 insertions(+), 1 deletion(-) > > --- a/btf_encoder.c > +++ b/btf_encoder.c > @@ -31,6 +31,8 @@ struct funcs_layout { > unsigned long mcount_start; > unsigned long mcount_stop; > unsigned long mcount_sec_idx; > + unsigned long opd_start; > + unsigned long opd_stop; > }; > > struct elf_function { > @@ -271,11 +273,24 @@ static int is_ftrace_func(struct elf_fun > return start <= addrs[r] && addrs[r] < end; > } > > +static int is_opd_func(struct elf_function *func, struct funcs_layout *fl) > +{ > + return fl->opd_start <= func->addr && func->addr < fl->opd_stop; > +} > + > static int setup_functions(struct btf_elf *btfe, struct funcs_layout *fl) > { > __u64 *addrs, count, i; > int functions_valid = 0; > bool kmod = false; > + GElf_Shdr shdr; > + Elf_Scn *sec; > + > + sec = elf_section_by_name(btfe->elf, &btfe->ehdr, &shdr, ".opd", NULL); > + if (sec) { > + fl->opd_start = shdr.sh_addr; > + fl->opd_stop = shdr.sh_addr + shdr.sh_size; > + } > > /* > * Check if we are processing vmlinux image and > @@ -322,7 +337,8 @@ static int setup_functions(struct btf_el > func->addr += func->sh_addr; > > /* Make sure function is within ftrace addresses. */ > - if (is_ftrace_func(func, addrs, count)) { > + if (is_opd_func(func, fl) || > + is_ftrace_func(func, addrs, count)) { > /* > * We iterate over sorted array, so we can easily skip > * not valid item and move following valid field into