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=-3.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, 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 83C84C433DF for ; Tue, 25 Aug 2020 06:50:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4BD5A2076C for ; Tue, 25 Aug 2020 06:50:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=canb.auug.org.au header.i=@canb.auug.org.au header.b="Dp8HZQrQ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729225AbgHYGul (ORCPT ); Tue, 25 Aug 2020 02:50:41 -0400 Received: from ozlabs.org ([203.11.71.1]:51733 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729116AbgHYGug (ORCPT ); Tue, 25 Aug 2020 02:50:36 -0400 Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.ozlabs.org (Postfix) with ESMTPSA id 4BbKPh4TtCz9sTK; Tue, 25 Aug 2020 16:50:32 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=canb.auug.org.au; s=201702; t=1598338234; bh=j9NrgxUjqWGE3IxuHRcqD4UBKle0ICvlV8D9udyUimw=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=Dp8HZQrQc6wRe+J1BEAo9CUpupQ4h3iULERXYZPL5jpU/z3dxhpNHZzB006zesX39 HtQINc6Nzi8aX9qEhXj7kzGOz5b8duQIhe9FBbcGaN63dtynXRWNbfcbEFUAzsNFIJ Gh9ISm8vtrlNPHxMSHq0Orx7EFHsj/vLDfxQCPxnYIcdF+Yn5eb4BPvxpJo5QrGuyy XrHr3K8ZApY+qSZkh09vMK9KJwxa5xv5yNJbDuDmgWjjUUr252P9Qx950effgVYJn+ +Jhm6Tuyy93fMvANbLxIGwK8FtO27IIutMZjl23AdPo9Ps4Q/onET+FmbMGuntn8OK +1NRusNoUGGSA== Date: Tue, 25 Aug 2020 16:50:29 +1000 From: Stephen Rothwell To: Alexei Starovoitov Cc: Daniel Borkmann , Alexei Starovoitov , Networking , Linux Next Mailing List , Linux Kernel Mailing List , David Miller Subject: Re: linux-next: build failure after merge of the bpf-next tree Message-ID: <20200825165029.795a8428@canb.auug.org.au> In-Reply-To: References: <20200821111111.6c04acd6@canb.auug.org.au> <20200825112020.43ce26bb@canb.auug.org.au> <20200825130445.655885f8@canb.auug.org.au> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="Sig_/tDU.O6cX1D9IrOpNIJF9IC5"; protocol="application/pgp-signature"; micalg=pgp-sha256 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --Sig_/tDU.O6cX1D9IrOpNIJF9IC5 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable Hi Alexei, On Mon, 24 Aug 2020 20:27:28 -0700 Alexei Starovoitov wrote: > > I didn't receive the first email you've replied to. > The build error is: > " > No libelf found > make[5]: *** [Makefile:284: elfdep] Error 1 > " > and build process stops because libelf is not found, right? > That is expected and necessary. > bpf_preload needs libbpf that depends on libelf. > The only 'fix' is to turn off bpf_preload. > It's off by default. > allmodconfig cannot build bpf_preload umd if there is no libelf. > There is CC_CAN_LINK that does feature detection. > We can extend scripts/cc-can-link.sh or add another script that > will do CC_CAN_LINK_LIBELF, but such approach doesn't scale. > imo it's cleaner to rely on feature detection by libbpf Makefile with > an error above instead of adding such knobs to top Kconfig. > Does it make sense? Sorry, but if this is not necessary to build the kernel, then an allmodconfig build needs to succeed so you need to do the detection and turn it off automatically. Or you could make it so that it has to be manually enabled in all circumstances. --=20 Cheers, Stephen Rothwell --Sig_/tDU.O6cX1D9IrOpNIJF9IC5 Content-Type: application/pgp-signature Content-Description: OpenPGP digital signature -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEENIC96giZ81tWdLgKAVBC80lX0GwFAl9EtLUACgkQAVBC80lX 0GwK6gf8DesCk38JfwT0m8g2BShvJEsTqH87hEuvVInFsGPaKvYcQTntETkYPPQa bF4jfkYOh5VlMGkgCLMGUw+GP48RuHKXt75oohyPzAEnDSwJhVAdG2q4LD4qhDJJ P+vN1s1VQ/qxreEGn0kqy66UJSWzavy1NKn2JXeEkacGKdQBqPhm1o1D+Cqay948 +JGt4A1kCx9uR+a1lWoafFLsdRgkMCbnKM+qTAhU+pnm67xsk+gO81MtmfX2/0Tw ocs0Uo2yl1K5u3RVciU83Ad7htWkqBvuFFiCXKIaGKNRPRKIZEnHG+X4hdAp9EdM Sbh7fMGJHGmjUV4MUvCVgzhUD65p+A== =Geul -----END PGP SIGNATURE----- --Sig_/tDU.O6cX1D9IrOpNIJF9IC5--