From patchwork Mon Jul 13 23:24:07 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 1328541 Return-Path: X-Original-To: incoming-bpf@patchwork.ozlabs.org Delivered-To: patchwork-incoming-bpf@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=bpf-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=reject dis=none) header.from=fb.com Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=fb.com header.i=@fb.com header.a=rsa-sha256 header.s=facebook header.b=Z3DVpg/K; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4B5KVq0WD7z9sQt for ; Tue, 14 Jul 2020 09:24:51 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726435AbgGMXYt (ORCPT ); Mon, 13 Jul 2020 19:24:49 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:25344 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726374AbgGMXYt (ORCPT ); Mon, 13 Jul 2020 19:24:49 -0400 Received: from pps.filterd (m0109331.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 06DNJ7tS013031 for ; Mon, 13 Jul 2020 16:24:48 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : mime-version : content-transfer-encoding : content-type; s=facebook; bh=aDOwrjjpwdtnPySuqg0BsRMlSG1fuB2xzY3H2P0dP+o=; b=Z3DVpg/KD2+gTFPkp3lzQznzVrYodGwjzkZofGjaa65HEKS505BsMXYZzBIkE9lJgjjR YaGzIHCajzY1KyX0+O8FXtcW7pEySSnTmAiywA4pL/fnoIRnSEqgfKEJo6TKhEVKifR+ nsJk2P6URbOINx6AZpNpmUpvyVJ6SqhE+y0= Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com with ESMTP id 327b8ht9e8-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Mon, 13 Jul 2020 16:24:48 -0700 Received: from intmgw001.08.frc2.facebook.com (2620:10d:c085:208::11) by mail.thefacebook.com (2620:10d:c085:21d::6) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1979.3; Mon, 13 Jul 2020 16:24:46 -0700 Received: by devbig012.ftw2.facebook.com (Postfix, from userid 137359) id A7C3D2EC4105; Mon, 13 Jul 2020 16:24:43 -0700 (PDT) Smtp-Origin-Hostprefix: devbig From: Andrii Nakryiko Smtp-Origin-Hostname: devbig012.ftw2.facebook.com To: , , , CC: , , Andrii Nakryiko , Anton Protopopov Smtp-Origin-Cluster: ftw2c04 Subject: [PATCH v2 bpf-next 0/2] Strip away modifiers from BPF skeleton global variables Date: Mon, 13 Jul 2020 16:24:07 -0700 Message-ID: <20200713232409.3062144-1-andriin@fb.com> X-Mailer: git-send-email 2.24.1 MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235, 18.0.687 definitions=2020-07-13_17:2020-07-13,2020-07-13 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 suspectscore=0 mlxlogscore=648 phishscore=0 impostorscore=0 clxscore=1015 bulkscore=0 spamscore=0 adultscore=0 mlxscore=0 lowpriorityscore=0 priorityscore=1501 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2007130170 X-FB-Internal: deliver Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Fix bpftool logic of stripping away const/volatile modifiers for all global variables during BPF skeleton generation. See patch #1 for details on when existing logic breaks and why it's important. Support special .strip_mods=true mode in btf_dump__emit_type_decl. Recent example of when this has caused problems can be found in [0]. [0] https://github.com/iovisor/bcc/pull/2994#issuecomment-650588533 Cc: Anton Protopopov Andrii Nakryiko (2): libbpf: support stripping modifiers for btf_dump tools/bpftool: strip away modifiers from global variables tools/bpf/bpftool/gen.c | 23 ++++++++----------- tools/lib/bpf/btf.h | 4 +++- tools/lib/bpf/btf_dump.c | 10 ++++++-- .../selftests/bpf/prog_tests/skeleton.c | 6 ++--- .../selftests/bpf/progs/test_skeleton.c | 6 +++-- 5 files changed, 28 insertions(+), 21 deletions(-)