From patchwork Thu Aug 1 07:24:05 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 1140311 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: incoming-bpf@patchwork.ozlabs.org Delivered-To: patchwork-incoming-bpf@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=bpf-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none 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.b="mTfx8wvM"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 45zhd21mgyz9sBF for ; Thu, 1 Aug 2019 17:24:38 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730780AbfHAHYg (ORCPT ); Thu, 1 Aug 2019 03:24:36 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:61232 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730760AbfHAHYf (ORCPT ); Thu, 1 Aug 2019 03:24:35 -0400 Received: from pps.filterd (m0044008.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x717OEMh016397 for ; Thu, 1 Aug 2019 00:24:34 -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-type; s=facebook; bh=RYLwBism92fkaf/clIOb5zGtUeHI4x+0NDU5AO1wlns=; b=mTfx8wvMFiHojiIG00tnne+c1TQ21cGeHq1RVw5ry+NokbadOJrJaFLD+pVBIG+/KdCf L6JEZsA0W1yg2MwNSX2Ybpcz57FTRUJ4Lqe48WjDmcWEom0bxqsUwFrlbxbOhiXQRef2 ThF1tRIebKLiWDmaADfU6b/5ZyoWfYn4FQ8= Received: from mail.thefacebook.com (mailout.thefacebook.com [199.201.64.23]) by mx0a-00082601.pphosted.com with ESMTP id 2u3k1x1h48-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA384 bits=256 verify=NOT) for ; Thu, 01 Aug 2019 00:24:34 -0700 Received: from mx-out.facebook.com (2620:10d:c081:10::13) by mail.thefacebook.com (2620:10d:c081:35::128) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA) id 15.1.1713.5; Thu, 1 Aug 2019 00:24:32 -0700 Received: by dev101.prn2.facebook.com (Postfix, from userid 137359) id 2FB0386167B; Thu, 1 Aug 2019 00:24:30 -0700 (PDT) Smtp-Origin-Hostprefix: dev From: Andrii Nakryiko Smtp-Origin-Hostname: dev101.prn2.facebook.com To: , , , , CC: , , Andrii Nakryiko Smtp-Origin-Cluster: prn2c23 Subject: [PATCH bpf] libbpf: set BTF FD for prog only when there is supported .BTF.ext data Date: Thu, 1 Aug 2019 00:24:05 -0700 Message-ID: <20190801072405.2835116-1-andriin@fb.com> X-Mailer: git-send-email 2.17.1 X-FB-Internal: Safe MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2019-08-01_04:, , signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1908010074 X-FB-Internal: deliver Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org 5d01ab7bac46 ("libbpf: fix erroneous multi-closing of BTF FD") introduced backwards-compatibility issue, manifesting itself as -E2BIG error returned on program load due to unknown non-zero btf_fd attribute value for BPF_PROG_LOAD sys_bpf() sub-command. This patch fixes bug by ensuring that we only ever associate BTF FD with program if there is a BTF.ext data that was successfully loaded into kernel, which automatically means kernel supports func_info/line_info and associated BTF FD for progs (checked and ensured also by BTF sanitization code). Fixes: 5d01ab7bac46 ("libbpf: fix erroneous multi-closing of BTF FD") Reported-by: Andrey Ignatov Signed-off-by: Andrii Nakryiko --- tools/lib/bpf/libbpf.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 2e84fa5b8479..2b57d7ea7836 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -2472,7 +2472,11 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt, load_attr.license = license; load_attr.kern_version = kern_version; load_attr.prog_ifindex = prog->prog_ifindex; - btf_fd = bpf_object__btf_fd(prog->obj); + /* if .BTF.ext was loaded, kernel supports associated BTF for prog */ + if (prog->obj->btf_ext) + btf_fd = bpf_object__btf_fd(prog->obj); + else + btf_fd = -1; load_attr.prog_btf_fd = btf_fd >= 0 ? btf_fd : 0; load_attr.func_info = prog->func_info; load_attr.func_info_rec_size = prog->func_info_rec_size;