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=-7.1 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 78B0FC47420 for ; Wed, 30 Sep 2020 15:40:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 28D3E2071E for ; Wed, 30 Sep 2020 15:40:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linuxtx.org header.i=@linuxtx.org header.b="KZrVCEC5" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725814AbgI3Pks (ORCPT ); Wed, 30 Sep 2020 11:40:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44056 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725837AbgI3Pkr (ORCPT ); Wed, 30 Sep 2020 11:40:47 -0400 Received: from mail-wr1-x442.google.com (mail-wr1-x442.google.com [IPv6:2a00:1450:4864:20::442]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3B9DFC0613D0 for ; Wed, 30 Sep 2020 08:40:47 -0700 (PDT) Received: by mail-wr1-x442.google.com with SMTP id x14so2326700wrl.12 for ; Wed, 30 Sep 2020 08:40:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxtx.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=/Kl2Qd9DygVOpqWB4QvrjPtrBb/z+P5PDh0hUEj2+t8=; b=KZrVCEC5/Wv+orMHsjVSmKr+y0GLZepxtFRVopYUKjsPsHSJZcZpbjRIy49UptMWRd FB45fGhhZPN/QyFOG3ugTk/cslCBzTtUEA9ca+dvifnguUB3DRBk6lGDJOe/ephxgHAZ zXPMsPerE9BfJZAQtQa914ki48jd/di3vfpEg= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=/Kl2Qd9DygVOpqWB4QvrjPtrBb/z+P5PDh0hUEj2+t8=; b=OuPohpgKjs7uOyS4RN41i25gZfbddmvs8hT8cDHWmxF6fYvUeELdL4R2qVl82FHL2S hLmpleZL9a1NeyXCK9qHkvuzyniUPvBS1PCTntG4Y+u69YwjU/tusdh2oLkLrusl0Kkd MGrRkHVbUwctYDlIFvJtuvQkgX5c0OEpV/UnkgICrrvpN8nUbBE3ItWdxqQhtk2vesxm +I7cehILRIxdQNqOv6uZoF1Pn7CJqSrF+U3PSv0V0Ea3WdCUD1sR7EQi+Fsw/O0ip1oB 6PW9hLSz6Ww/YqwrEKvzrcVuc17g9bSk8pCmx6mTAhi90xNM7UU+KoZB9lelFfQEQvIS BDdg== X-Gm-Message-State: AOAM533aw2463jovUYVfZTBkakQeFSTy1btJ5iQqlNf6pbPzJzCpo8ys vLVm2CHAao0IHJUAzS+Oe1m/eIZlXmDJVu33aMh0Lw== X-Google-Smtp-Source: ABdhPJyovthY6wL6WkzoBh46/ttwHT8LSDLHRz39NUSk95y8G78RCIWbtSvH4XGpkqyG0BfoG8t1cXgZCGMmIy/KDFo= X-Received: by 2002:adf:e9c1:: with SMTP id l1mr3876277wrn.68.1601480445753; Wed, 30 Sep 2020 08:40:45 -0700 (PDT) MIME-Version: 1.0 References: <20200929105929.719230296@linuxfoundation.org> <20200929105931.461063397@linuxfoundation.org> In-Reply-To: From: Justin Forbes Date: Wed, 30 Sep 2020 10:40:33 -0500 Message-ID: Subject: Re: [PATCH 5.8 35/99] tools/libbpf: Avoid counting local symbols in ABI check To: Tony Ambardar Cc: Greg Kroah-Hartman , LKML , Stable , Alexei Starovoitov , Andrii Nakryiko , Sasha Levin , Michael Ellerman Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Sep 30, 2020 at 12:02 AM Tony Ambardar wrote: > > [adding Michael Ellerman, linux-ppc maintainer] > > Hello Justin, > > On Tue, 29 Sep 2020 at 14:54, Justin Forbes wrote: > > > > On Tue, Sep 29, 2020 at 6:53 AM Greg Kroah-Hartman > > wrote: > > > > > > From: Tony Ambardar > > > > > > [ Upstream commit 746f534a4809e07f427f7d13d10f3a6a9641e5c3 ] > > > > > > Encountered the following failure building libbpf from kernel 5.8.5 sources > > > with GCC 8.4.0 and binutils 2.34: (long paths shortened) > > > > > > Warning: Num of global symbols in sharedobjs/libbpf-in.o (234) does NOT > > > match with num of versioned symbols in libbpf.so (236). Please make sure > > > all LIBBPF_API symbols are versioned in libbpf.map. > > > # --- libbpf_global_syms.tmp 2020-09-02 07:30:58.920084380 +0000 > > > # +++ libbpf_versioned_syms.tmp 2020-09-02 07:30:58.924084388 +0000 > > > @@ -1,3 +1,5 @@ > > > +_fini > > > +_init > > > bpf_btf_get_fd_by_id > > > bpf_btf_get_next_id > > > bpf_create_map > > > make[4]: *** [Makefile:210: check_abi] Error 1 > > > > > > Investigation shows _fini and _init are actually local symbols counted > > > amongst global ones: > > > > > > $ readelf --dyn-syms --wide libbpf.so|head -10 > > > > > > Symbol table '.dynsym' contains 343 entries: > > > Num: Value Size Type Bind Vis Ndx Name > > > 0: 00000000 0 NOTYPE LOCAL DEFAULT UND > > > 1: 00004098 0 SECTION LOCAL DEFAULT 11 > > > 2: 00004098 8 FUNC LOCAL DEFAULT 11 _init@@LIBBPF_0.0.1 > > > 3: 00023040 8 FUNC LOCAL DEFAULT 14 _fini@@LIBBPF_0.0.1 > > > 4: 00000000 0 OBJECT GLOBAL DEFAULT ABS LIBBPF_0.0.4 > > > 5: 00000000 0 OBJECT GLOBAL DEFAULT ABS LIBBPF_0.0.1 > > > 6: 0000ffa4 8 FUNC GLOBAL DEFAULT 12 bpf_object__find_map_by_offset@@LIBBPF_0.0.1 > > > > > > A previous commit filtered global symbols in sharedobjs/libbpf-in.o. Do the > > > same with the libbpf.so DSO for consistent comparison. > > > > > > Fixes: 306b267cb3c4 ("libbpf: Verify versioned symbols") > > > Signed-off-by: Tony Ambardar > > > Signed-off-by: Alexei Starovoitov > > > Acked-by: Andrii Nakryiko > > > Link: https://lore.kernel.org/bpf/20200905214831.1565465-1-Tony.Ambardar@gmail.com > > > Signed-off-by: Sasha Levin > > > > This seems to work everywhere else, but breaks PPC64LE. > > > > I also ran into a PPC build error while working on some bpf problems, > but it seemed > like a pre-existing PPC issue. I did submit an upstream fix, which is > marked for stable > and being reviewed by Michael. See here for discussion and the patch: > https://lkml.org/lkml/2020/9/17/668. > > Is that the same problem you encountered? Does that patch address your issue? It is not, the issue I see is: Warning: Num of global symbols in sharedobjs/libbpf-in.o (259) does NOT match with num of versioned symbols in libbpf.so (50). Please make sure all LIBBPF_API symbols are versioned in libbpf.map. I only see it on ppc64le with this patch, all other arch that Fedora builds are fine (x86_64, i686, aarch64, armv7, s390). If I revert this patch, all builds succeed. We are using gcc 10.2.1 though. Justin > > Thanks, > Tony > > > Justin > > > > > --- > > > tools/lib/bpf/Makefile | 2 ++ > > > 1 file changed, 2 insertions(+) > > > > > > --- a/tools/lib/bpf/Makefile > > > +++ b/tools/lib/bpf/Makefile > > > @@ -152,6 +152,7 @@ GLOBAL_SYM_COUNT = $(shell readelf -s -- > > > awk '/GLOBAL/ && /DEFAULT/ && !/UND/ {print $$NF}' | \ > > > sort -u | wc -l) > > > VERSIONED_SYM_COUNT = $(shell readelf --dyn-syms --wide $(OUTPUT)libbpf.so | \ > > > + awk '/GLOBAL/ && /DEFAULT/ && !/UND/ {print $$NF}' | \ > > > grep -Eo '[^ ]+@LIBBPF_' | cut -d@ -f1 | sort -u | wc -l) > > > > > > CMD_TARGETS = $(LIB_TARGET) $(PC_FILE) > > > @@ -219,6 +220,7 @@ check_abi: $(OUTPUT)libbpf.so > > > awk '/GLOBAL/ && /DEFAULT/ && !/UND/ {print $$NF}'| \ > > > sort -u > $(OUTPUT)libbpf_global_syms.tmp; \ > > > readelf --dyn-syms --wide $(OUTPUT)libbpf.so | \ > > > + awk '/GLOBAL/ && /DEFAULT/ && !/UND/ {print $$NF}'| \ > > > grep -Eo '[^ ]+@LIBBPF_' | cut -d@ -f1 | \ > > > sort -u > $(OUTPUT)libbpf_versioned_syms.tmp; \ > > > diff -u $(OUTPUT)libbpf_global_syms.tmp \ > > > > > >