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=-11.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS autolearn=ham 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 9CA94C48BE5 for ; Thu, 17 Jun 2021 20:39:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 82AE1613CE for ; Thu, 17 Jun 2021 20:39:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232573AbhFQUlm (ORCPT ); Thu, 17 Jun 2021 16:41:42 -0400 Received: from mail.kernel.org ([198.145.29.99]:35290 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232286AbhFQUlk (ORCPT ); Thu, 17 Jun 2021 16:41:40 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id AAA3F61042; Thu, 17 Jun 2021 20:39:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1623962372; bh=PiSYIgAwlBxwVk9rQZj+Fov2cSjgbRGcKNP+q9UIfcc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=KVaTB2XalR7EM+snBFqkVTgVaN5fnxFt0beEzqtroqGv8KBFRkU8wSM//BsMc8frK bIKKMyghFB3R8wJcdGuqtPygbGmRcg5StLTv70kyiYf6dOLyQIMdWwV0mrWeVTT9cQ cBJb5otlA+o2vXncTC9EXoYA7XZ3ohOAR9TU1Jul1TL9A16Agc1qApSOL6JfBKWRrY MLN0Rp68zalakw4paGzZEzA1DTUdRXe2dYtCSqR3rTyEwR8EjyjCqYmiUJSdGPJeIw zF19hUMITsaBrZt4gETpmiL+WiwN/0yO4DD/KQ1iswTk7CcTL8Xe+nLdGcy+TqJys8 WMAocMgLrcmCg== Received: by quaco.ghostprotocols.net (Postfix, from userid 1000) id 711C140B1A; Thu, 17 Jun 2021 17:39:29 -0300 (-03) Date: Thu, 17 Jun 2021 17:39:29 -0300 From: Arnaldo Carvalho de Melo To: Andrii Nakryiko Cc: Arnaldo Carvalho de Melo , Yonghong Song , bpf , dwarves@vger.kernel.org, siudin@fb.com Subject: Re: latest pahole breaks libbpf CI and let's talk about staging Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Url: http://acmel.wordpress.com Precedence: bulk List-ID: X-Mailing-List: dwarves@vger.kernel.org Em Thu, Jun 17, 2021 at 01:00:11PM -0700, Andrii Nakryiko escreveu: > On Thu, Jun 17, 2021 at 7:48 AM Arnaldo Carvalho de Melo > wrote: > > > > Em Wed, Jun 16, 2021 at 03:36:54PM -0700, Andrii Nakryiko escreveu: > > > On Wed, Jun 16, 2021 at 1:41 PM Arnaldo Carvalho de Melo wrote: > > > > And if I use pahole's BTF loader I find the info about that function: > > > > > > > > [acme@seventh linux]$ strace -e openat -o /tmp/bla pfunct -F btf tcp_cong_avoid_ai ; grep vmlinux /tmp/bla > > > > void tcp_cong_avoid_ai(struct tcp_sock * tp, u32 w, u32 acked); > > > > openat(AT_FDCWD, "/sys/kernel/btf/vmlinux", O_RDONLY) = 3 > > > > > > > > So this should be unrelated to the breakage you noticed in the CI. > > > > > > > > I'm trying to to reproduce the CI breakage by building the kernel and > > > > running selftests after a reboot. > > > > > > > > I suspect I'm missing something, can you see what it is? > > > > > > Oh, I didn't realize initially what it is. This is not kernel-related, > > > you are right. You just need newer Clang. Can you please use nightly > > > version or build from sources? Basically, your Clang is too old and it > > > doesn't generate BTF information for extern functions in BPF code. > > > > Oh well, I thought that that clang was new enough, the system being > > Fedora rawhide: > > > > [acme@seventh ~]$ clang -v |& head -1 > > clang version 12.0.0 (https://github.com/llvm/llvm-project 87369c626114ae17f4c637635c119e6de0856a9a) > > > > I'm now building the single-repo main... > > > > Would you consider a patch for libbpf that would turn this: > > > > > > > libbpf: failed to find BTF for extern 'tcp_cong_avoid_ai' [27] section: -2 > > > > > Error: failed to open BPF object file: No such file or directory > > > > > make: *** [Makefile:460: /mnt/linux/tools/testing/selftests/bpf/bpf_cubic.skel.h] Error 255 > > > > > make: *** Deleting file '/mnt/linux/tools/testing/selftests/bpf/bpf_cubic.skel.h' > > > > > make: Leaving directory '/mnt/linux/tools/testing/selftests/bpf' > > > > Into: > > > > libbpf: failed to find BTF for extern 'tcp_cong_avoid_ai' [27] section: -2 > > HINT: Please update your clang/llvm toolchain to at least cset abcdef123456 > > HINT: That is where clang started generating BTF information for extern functions in BPF code. > > > > ? > > > > :-) > > I'd rather not :) Not even a "please update clang?" "-2" and "Error 255" doesn't seem that helpful :-\ - Arnaldo