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=-5.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 39745C4167B for ; Mon, 7 Dec 2020 16:53:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 048352388D for ; Mon, 7 Dec 2020 16:53:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727518AbgLGQxF (ORCPT ); Mon, 7 Dec 2020 11:53:05 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:22261 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726519AbgLGQxF (ORCPT ); Mon, 7 Dec 2020 11:53:05 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1607359898; 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=C2+iW4RaCunmJadgGixc7tSG+nCepKzvprLYvqLbaDo=; b=TG5p+UjSWsf0QrXyV7JCHCxeTJcE1D/iK676h28pKU1KGyeY9i2fq3zj74FRSsb6t/RHR0 AmeWA7hYFxSeQicLvmh8qFKx2QEfblAr0S4xYZyZp8KbXy9zFnWJ4tp71KAee4F/63FcUM w68U05VvGD48cYzlmXg6h4djrzfQZNI= Received: from mail-wm1-f69.google.com (mail-wm1-f69.google.com [209.85.128.69]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-399-M-VrwJplOAKX4biVNqaWow-1; Mon, 07 Dec 2020 11:51:37 -0500 X-MC-Unique: M-VrwJplOAKX4biVNqaWow-1 Received: by mail-wm1-f69.google.com with SMTP id r1so5545237wmn.8 for ; Mon, 07 Dec 2020 08:51:36 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:in-reply-to:references:date :message-id:mime-version:content-transfer-encoding; bh=C2+iW4RaCunmJadgGixc7tSG+nCepKzvprLYvqLbaDo=; b=NLRg8/VEMYzjleztoM6wOIjORBcSiDxgXU67Yqz1mOcPqR2vcosG2IF3udWBqcMaLp 2W/tlq9n+OIZM50YxNKItOHM1t6EBeHADpsSPvHAPQQxsYmiu+WZmnxv6Juh8lnRzYqE Z5x/44O9I4d7TscuU81A4G2sijDhjIr0alRIdr416yyhmigZqQphZ0IShO8ylf3Xkz4z ddN0EXuq099TgOi2WrUgR/DSvasF9L5/ndzDC7zHnkmzxRa47KeJXUP3AdfdDDBIMQsr nPOKPuoRxRlPHaywzUGI6/bEsoSzahS1hdYtjJ/Tdh0vcm0t7G8pNfPGcaUmNXfMYz6y zieA== X-Gm-Message-State: AOAM531t9ozAKuxRBbaP7YJL0tAxqQWRQP4YER5GGu8rFBAEVJ4dhkp7 DNuqlKMDxqyCd5hc1Z9KbfewtFGPgx+KT03Wf0H0PP3efG1wTQYxUj0ODNKnxIYL9Mc2n4vCA7U yRltoas9ddGi7 X-Received: by 2002:adf:e512:: with SMTP id j18mr5561872wrm.52.1607359895968; Mon, 07 Dec 2020 08:51:35 -0800 (PST) X-Google-Smtp-Source: ABdhPJxJhgXm8i68ygvuAI76n1Ld07e+zzasG8fkWlsMfzy6eEkdxe/YZqHM35kHtQ7YFWmnEnnGew== X-Received: by 2002:adf:e512:: with SMTP id j18mr5561854wrm.52.1607359895796; Mon, 07 Dec 2020 08:51:35 -0800 (PST) Received: from alrua-x1.borgediget.toke.dk ([45.145.92.2]) by smtp.gmail.com with ESMTPSA id b12sm477869wmj.2.2020.12.07.08.51.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 07 Dec 2020 08:51:35 -0800 (PST) Received: by alrua-x1.borgediget.toke.dk (Postfix, from userid 1000) id B59471843F5; Mon, 7 Dec 2020 17:51:34 +0100 (CET) From: Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= To: Alexei Starovoitov Cc: Andrii Nakryiko , Yonghong Song , bpf Subject: Re: Latest libbpf fails to load programs compiled with old LLVM In-Reply-To: References: <87lfeebwpu.fsf@toke.dk> <10679e62-50a2-4c01-31d2-cb79c01e4cbf@fb.com> <87r1o59aoc.fsf@toke.dk> <6801fcdb-932e-c185-22db-89987099b553@fb.com> <875z5d7ufl.fsf@toke.dk> <878sa9619d.fsf@toke.dk> X-Clacks-Overhead: GNU Terry Pratchett Date: Mon, 07 Dec 2020 17:51:34 +0100 Message-ID: <874kkx5zl5.fsf@toke.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Alexei Starovoitov writes: > On Mon, Dec 7, 2020 at 8:15 AM Toke H=C3=B8iland-J=C3=B8rgensen wrote: >> >> Alexei Starovoitov writes: >> >> > On Mon, Dec 7, 2020 at 3:03 AM Toke H=C3=B8iland-J=C3=B8rgensen wrote: >> >> >> >> Wait, what? This is a regression that *breaks people's programs* on >> >> compiler versions that are still very much in the wild! I mean, fine = if >> >> you don't want to support new features on such files, but then surely= we >> >> can at least revert back to the old behaviour? >> > >> > Those folks that care about compiling with old llvm would have to stick >> > to whatever loader they have instead of using libbpf. >> > It's not a backward compatibility breakage. >> >> What? It's a change in libbpf that breaks loading of existing BPF object >> files that were working (with libbpf) before. If that's not a backward >> compatibility break then that term has lost all meaning. > > The user space library is not a kernel. > The library will change its interface. It will remove functions, features= , etc. > That's what .map is for. Right, OK, so how do I use .map to get the old behaviour here? That's all I'm asking for, really... -Toke