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=-7.4 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 AF249C433E0 for ; Wed, 3 Feb 2021 17:22:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6809C64F4B for ; Wed, 3 Feb 2021 17:22:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231233AbhBCRVg (ORCPT ); Wed, 3 Feb 2021 12:21:36 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35998 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230154AbhBCRVf (ORCPT ); Wed, 3 Feb 2021 12:21:35 -0500 Received: from merlin.infradead.org (merlin.infradead.org [IPv6:2001:8b0:10b:1231::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 79E72C0613ED for ; Wed, 3 Feb 2021 09:20:56 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=Content-Transfer-Encoding:Content-Type: In-Reply-To:MIME-Version:Date:Message-ID:From:References:To:Subject:Sender: Reply-To:Cc:Content-ID:Content-Description; bh=YYVKkQ04NXHmPPt6gyavDzAoDyRwJzchdnbmrPLP+KQ=; b=ZMCvDg8IHPYTDfqtpKLnmEL1QA qgyFSo6LIqu9D+raKyyaLwIHkELkTRxQQ1nA/dwqoK8U2erayYucFGxTIhtzIP53GfgOgY1Y2yAiV P3pDqF7vx3PMaOEANzbWaLRkPn1xShhKxsHswuL5c3msQiFc8aSpD6O7OXIlFikenoDIgy1kTItzu 7sYVOCgVm/iwbIDsv9s1GBIyY7TZxrGaKKKqf4m0pXD5vsZNX/u20T7LyQn3wUEinggqURzENZ2yp bjIhxS5ySnm8oMyoSIwPRhvjLAAldcpjAeybM8utKcKCVninhLzjSkwQ6vvkRB7aoMb3gTxJQ7lSk NwwpDrMA==; Received: from [2601:1c0:6280:3f0::aec2] by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1l7Lpm-0008Rk-Dh; Wed, 03 Feb 2021 17:20:54 +0000 Subject: Re: finding libelf To: =?UTF-8?Q?Toke_H=c3=b8iland-J=c3=b8rgensen?= , bpf References: <8a6894e9-71ef-09e3-64fa-bf6794fc6660@infradead.org> <87eehxa06v.fsf@toke.dk> From: Randy Dunlap Message-ID: Date: Wed, 3 Feb 2021 09:20:51 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.4.0 MIME-Version: 1.0 In-Reply-To: <87eehxa06v.fsf@toke.dk> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On 2/3/21 2:57 AM, Toke Høiland-Jørgensen wrote: > Randy Dunlap writes: > >> Hi, >> >> I see this sometimes when building a kernel: (on x86_64, >> with today's linux-next 20210202): >> >> >> CONFIG_CGROUP_BPF=y >> CONFIG_BPF=y >> CONFIG_BPF_SYSCALL=y >> CONFIG_ARCH_WANT_DEFAULT_BPF_JIT=y >> CONFIG_BPF_PRELOAD=y >> CONFIG_BPF_PRELOAD_UMD=m >> CONFIG_HAVE_EBPF_JIT=y >> >> >> Auto-detecting system features: >> ... libelf: [ [31mOFF[m ] >> ... zlib: [ [31mOFF[m ] >> ... bpf: [ [31mOFF[m ] >> >> No libelf found >> make[5]: [Makefile:287: elfdep] Error 1 (ignored) >> No zlib found >> make[5]: [Makefile:290: zdep] Error 1 (ignored) >> BPF API too old >> make[5]: [Makefile:293: bpfdep] Error 1 (ignored) >> >> >> but pkg-config tells me: >> >> $ pkg-config --modversion libelf >> 0.168 >> $ pkg-config --libs libelf >> -lelf >> >> >> Any ideas? > > This usually happens because there's a stale cache of the feature > detection tests lying around somewhere. Look for a 'feature' directory > in whatever subdir you got that error. Just removing the feature > directory usually fixes this; I've fixed a couple of places where this > is not picked up by 'make clean' (see, e.g., 9d9aae53b96d ("bpf/preload: > Make sure Makefile cleans up after itself, and add .gitignore")) but I > wouldn't be surprised if there are still some that are broken. Hi, Thanks for replying. I removed the feature subdir and still got this build error, so I removed everything in BUILDDIR/kernel/bpf/preload and rebuilt -- and still got the same libelf build error. -- ~Randy