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=-0.9 required=3.0 tests=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 57A3FC34056 for ; Wed, 19 Feb 2020 20:06:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 289712176D for ; Wed, 19 Feb 2020 20:06:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="MnocYY4u" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727125AbgBSUGc (ORCPT ); Wed, 19 Feb 2020 15:06:32 -0500 Received: from us-smtp-1.mimecast.com ([205.139.110.61]:37041 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726651AbgBSUGb (ORCPT ); Wed, 19 Feb 2020 15:06:31 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1582142790; 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=rSgZmzP4k8CmOEp7jZmOsNnNYRQvUnS1sXvQgXw+mZI=; b=MnocYY4uPVq3trk3OSaRbDPiexbfFYBwKcj6D+oy3hf0M0XQwJY/CR9zmJwoJ9T0foXHDP N4jkEoL8Ll6GXHScCF4a2s4I6ghEzerP7CMGxZZYNtQswCqqu0hQIAwQGT1Gz7acBbjcIR m3RzUd/ogJuxoh44SQ6Fu3skUyaMJy0= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-304-7KKjfjZ3OPKe4pAB1JMKZg-1; Wed, 19 Feb 2020 15:06:24 -0500 X-MC-Unique: 7KKjfjZ3OPKe4pAB1JMKZg-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 8411E800D4E; Wed, 19 Feb 2020 20:06:22 +0000 (UTC) Received: from carbon (ovpn-200-26.brq.redhat.com [10.40.200.26]) by smtp.corp.redhat.com (Postfix) with ESMTP id 4F22638D; Wed, 19 Feb 2020 20:06:10 +0000 (UTC) Date: Wed, 19 Feb 2020 21:06:09 +0100 From: Jesper Dangaard Brouer To: Andrii Nakryiko Cc: Alexei Starovoitov , Andrii Nakryiko , "netdev@vger.kernel.org" , BPF-dev-list , Daniel Borkmann , David Miller , LKML , Greg Kroah-Hartman , Anders Roxell , Toke =?UTF-8?B?SMO4aWxhbmQtSsO4cmdlbnNlbg==?= , brouer@redhat.com Subject: Re: Kernel 5.5.4 build fail for BPF-selftests with latest LLVM Message-ID: <20200219210609.20a097fb@carbon> In-Reply-To: References: <20200219133012.7cb6ac9e@carbon> <20200219180348.40393e28@carbon> <20200219192854.6b05b807@carbon> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 19 Feb 2020 10:38:45 -0800 Andrii Nakryiko wrote: > On Wed, Feb 19, 2020 at 10:29 AM Jesper Dangaard Brouer > wrote: > > > > On Wed, 19 Feb 2020 09:38:50 -0800 > > Andrii Nakryiko wrote: > > > > > On Wed, Feb 19, 2020 at 9:04 AM Jesper Dangaard Brouer > > > wrote: > > > > > > > > On Wed, 19 Feb 2020 08:41:27 -0800 > > > > Alexei Starovoitov wrote: > > > > > > > > > On Wed, Feb 19, 2020 at 4:30 AM Jesper Dangaard Brouer > > > > > wrote: > > > > > > > > > > > > I'm willing to help out, such that we can do either version or feature > > > > > > detection, to either skip compiling specific test programs or at least > > > > > > give users a proper warning of they are using a too "old" LLVM version. > > > > > ... > > > > > > progs/test_core_reloc_bitfields_probed.c:47:13: error: use of unknown builtin '__builtin_preserve_field_info' [-Wimplicit-function-declaration] > > > > > > out->ub1 = BPF_CORE_READ_BITFIELD_PROBED(in, ub1); > > > > > > > > > > imo this is proper warning message already. > > > > > > > > This is an error, not a warning. The build breaks as the make process stops. > > > > > > > > > > Latest Clang was a requirement for building and running all selftests > > > for a long time now. There were few previous discussions on mailing > > > list about this and each time the conclusion was the same: latest > > > Clang is a requirement for BPF selftests. > > > > The latest Clang is 9.0.1, and it doesn't build with that. > > Latest as in "latest built from sources". When I download a specific kernel release, how can I know what LLVM git-hash or version I need (to use BPF-selftests)? Do you think it is reasonable to require end-users to compile their own bleeding edge version of LLVM, to use BPF-selftests? I do hope that some end-users of BPF-selftests will be CI-systems. That also implies that CI-system maintainers need to constantly do "latest built from sources" of LLVM git-tree to keep up. Is that a reasonable requirement when buying a CI-system in the cloud? -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer