From patchwork Thu Dec 3 03:51:50 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 11947665 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=-12.0 required=3.0 tests=BAYES_00,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 4C854C63777 for ; Thu, 3 Dec 2020 03:52:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E6A3E22228 for ; Thu, 3 Dec 2020 03:52:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727449AbgLCDwv convert rfc822-to-8bit (ORCPT ); Wed, 2 Dec 2020 22:52:51 -0500 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:13502 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726734AbgLCDwv (ORCPT ); Wed, 2 Dec 2020 22:52:51 -0500 Received: from pps.filterd (m0044012.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 0B33l6Jn005594 for ; Wed, 2 Dec 2020 19:52:10 -0800 Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com with ESMTP id 3560xg0kj9-3 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Wed, 02 Dec 2020 19:52:10 -0800 Received: from intmgw004.08.frc2.facebook.com (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:83::6) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1979.3; Wed, 2 Dec 2020 19:52:08 -0800 Received: by devbig012.ftw2.facebook.com (Postfix, from userid 137359) id 706C42ECA822; Wed, 2 Dec 2020 19:52:06 -0800 (PST) From: Andrii Nakryiko To: , , , CC: , Subject: [PATCH v5 bpf-next 00/14] Support BTF-powered BPF tracing programs for kernel modules Date: Wed, 2 Dec 2020 19:51:50 -0800 Message-ID: <20201203035204.1411380-1-andrii@kernel.org> X-Mailer: git-send-email 2.24.1 X-FB-Internal: Safe X-Proofpoint-UnRewURL: 0 URL was un-rewritten MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.312,18.0.737 definitions=2020-12-03_01:2020-11-30,2020-12-03 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 mlxlogscore=999 priorityscore=1501 impostorscore=0 bulkscore=0 clxscore=1015 spamscore=0 phishscore=0 malwarescore=0 suspectscore=2 adultscore=0 mlxscore=0 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2012030020 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net This patch sets extends kernel and libbpf with support for attaching BTF-powered raw tracepoint (tp_btf) and tracing (fentry/fexit/fmod_ret/lsm) BPF programs to BPF hooks defined in kernel modules. As part of that, libbpf now supports performing CO-RE relocations against types in kernel module BTFs, in addition to existing vmlinux BTF support. Kernel UAPI for BPF_PROG_LOAD now allows to specify kernel module (or vmlinux) BTF object FD in attach_btf_obj_fd field, aliased to attach_prog_fd. This is used to identify which BTF object needs to be used for finding BTF type by provided attach_btf_id. This patch set also sets up a convenient and fully-controlled custom kernel module (called "bpf_testmod"), that is a predictable playground for all the BPF selftests, that rely on module BTFs. Currently pahole doesn't generate BTF_KIND_FUNC info for ftrace-able static functions in kernel modules, so expose traced function in bpf_sidecar.ko. Once pahole is enhanced, we can go back to static function. From end user perspective there are no extra actions that need to happen. Libbpf will continue searching across all kernel module BTFs, if desired attach BTF type is not found in vmlinux. That way it doesn't matter if BPF hook that user is trying to attach to is built into vmlinux image or is loaded in kernel module. v4->v5: - use FD to specify BTF object (Alexei); - move prog->aux->attach_btf putting into bpf_prog_free() for consistency with putting prog->aux->dst_prog; - fix BTF FD leak(s) in libbpf; v3->v4: - merge together patch sets [0] and [1]; - avoid increasing bpf_reg_state by reordering fields (Alexei); - preserve btf_data_size in struct module; v2->v3: - fix subtle uninitialized variable use in BTF ID iteration code; v1->v2: - module_put() inside preempt_disable() region (Alexei); - bpf_sidecar -> bpf_testmod rename (Alexei); - test_progs more relaxed handling of bpf_testmod; - test_progs marks skipped sub-tests properly as SKIP now. [0] https://patchwork.kernel.org/project/netdevbpf/list/?series=393677&state=* [1] https://patchwork.kernel.org/project/netdevbpf/list/?series=393679&state=* Andrii Nakryiko (14): bpf: fix bpf_put_raw_tracepoint()'s use of __module_address() bpf: keep module's btf_data_size intact after load libbpf: add internal helper to load BTF data by FD libbpf: refactor CO-RE relocs to not assume a single BTF object libbpf: add kernel module BTF support for CO-RE relocations selftests/bpf: add bpf_testmod kernel module for testing selftests/bpf: add support for marking sub-tests as skipped selftests/bpf: add CO-RE relocs selftest relying on kernel module BTF bpf: remove hard-coded btf_vmlinux assumption from BPF verifier bpf: allow to specify kernel module BTFs when attaching BPF programs libbpf: factor out low-level BPF program loading helper libbpf: support attachment of BPF tracing programs to kernel modules selftests/bpf: add tp_btf CO-RE reloc test for modules selftests/bpf: add fentry/fexit/fmod_ret selftest for kernel module include/linux/bpf.h | 13 +- include/linux/bpf_verifier.h | 28 +- include/linux/btf.h | 6 +- include/uapi/linux/bpf.h | 7 +- kernel/bpf/btf.c | 70 ++- kernel/bpf/core.c | 2 + kernel/bpf/syscall.c | 74 ++- kernel/bpf/verifier.c | 77 +-- kernel/module.c | 1 - kernel/trace/bpf_trace.c | 8 +- net/ipv4/bpf_tcp_ca.c | 3 +- tools/include/uapi/linux/bpf.h | 7 +- tools/lib/bpf/bpf.c | 101 ++-- tools/lib/bpf/btf.c | 61 ++- tools/lib/bpf/libbpf.c | 500 ++++++++++++++---- tools/lib/bpf/libbpf_internal.h | 31 ++ tools/testing/selftests/bpf/.gitignore | 1 + tools/testing/selftests/bpf/Makefile | 12 +- .../selftests/bpf/bpf_testmod/.gitignore | 6 + .../selftests/bpf/bpf_testmod/Makefile | 20 + .../bpf/bpf_testmod/bpf_testmod-events.h | 36 ++ .../selftests/bpf/bpf_testmod/bpf_testmod.c | 52 ++ .../selftests/bpf/bpf_testmod/bpf_testmod.h | 14 + .../selftests/bpf/prog_tests/core_reloc.c | 80 ++- .../selftests/bpf/prog_tests/module_attach.c | 53 ++ .../selftests/bpf/progs/core_reloc_types.h | 17 + .../bpf/progs/test_core_reloc_module.c | 96 ++++ .../selftests/bpf/progs/test_module_attach.c | 66 +++ tools/testing/selftests/bpf/test_progs.c | 65 ++- tools/testing/selftests/bpf/test_progs.h | 1 + 30 files changed, 1228 insertions(+), 280 deletions(-) create mode 100644 tools/testing/selftests/bpf/bpf_testmod/.gitignore create mode 100644 tools/testing/selftests/bpf/bpf_testmod/Makefile create mode 100644 tools/testing/selftests/bpf/bpf_testmod/bpf_testmod-events.h create mode 100644 tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c create mode 100644 tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.h create mode 100644 tools/testing/selftests/bpf/prog_tests/module_attach.c create mode 100644 tools/testing/selftests/bpf/progs/test_core_reloc_module.c create mode 100644 tools/testing/selftests/bpf/progs/test_module_attach.c