From patchwork Thu Feb 25 23:43:17 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Song Liu X-Patchwork-Id: 12105225 X-Patchwork-Delegate: bpf@iogearbox.net 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=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 6E271C433E9 for ; Thu, 25 Feb 2021 23:45:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4578064F2F for ; Thu, 25 Feb 2021 23:45:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232938AbhBYXos (ORCPT ); Thu, 25 Feb 2021 18:44:48 -0500 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:25290 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232791AbhBYXoc (ORCPT ); Thu, 25 Feb 2021 18:44:32 -0500 Received: from pps.filterd (m0044012.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 11PNYfD2027079 for ; Thu, 25 Feb 2021 15:43:52 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding : content-type; s=facebook; bh=xE5jfbmD7ggvOtV/7xXWeCQmjvzq79ebUAY3GevP7YY=; b=TvVQrF5jlR1RUpcgWlU1hQo6+ncsVcwe1zpTKKpxyqIz5v45lDcmRI+oVnIeUlxLJ4Um 0eMUus1JqkPWHipxUuY8pLvz/DiqKSwVAszyBmPnfWQgVBwk5/rjbftrB3mkQBJJhUh+ OL2JnCzhDI721AA3APhv/z8PbuEgeSdgazg= Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com with ESMTP id 36xkfk8r7k-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Thu, 25 Feb 2021 15:43:52 -0800 Received: from intmgw001.06.ash9.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; Thu, 25 Feb 2021 15:43:51 -0800 Received: by devbig006.ftw2.facebook.com (Postfix, from userid 4523) id 38A4C62E1BF5; Thu, 25 Feb 2021 15:43:44 -0800 (PST) From: Song Liu To: , , CC: , , , , Song Liu Subject: [PATCH v6 bpf-next 4/6] selftests/bpf: test deadlock from recursive bpf_task_storage_[get|delete] Date: Thu, 25 Feb 2021 15:43:17 -0800 Message-ID: <20210225234319.336131-5-songliubraving@fb.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20210225234319.336131-1-songliubraving@fb.com> References: <20210225234319.336131-1-songliubraving@fb.com> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.369,18.0.761 definitions=2021-02-25_15:2021-02-24,2021-02-25 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 mlxscore=0 suspectscore=0 adultscore=0 clxscore=1015 malwarescore=0 phishscore=0 impostorscore=0 lowpriorityscore=0 mlxlogscore=921 spamscore=0 bulkscore=0 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2102250179 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Add a test with recursive bpf_task_storage_[get|delete] from fentry programs on bpf_local_storage_lookup and bpf_local_storage_update. Without proper deadlock prevent mechanism, this test would cause deadlock. Signed-off-by: Song Liu --- .../bpf/prog_tests/task_local_storage.c | 23 ++++++ .../selftests/bpf/progs/task_ls_recursion.c | 70 +++++++++++++++++++ 2 files changed, 93 insertions(+) create mode 100644 tools/testing/selftests/bpf/progs/task_ls_recursion.c diff --git a/tools/testing/selftests/bpf/prog_tests/task_local_storage.c b/tools/testing/selftests/bpf/prog_tests/task_local_storage.c index dbb7525cdd567..035c263aab1b1 100644 --- a/tools/testing/selftests/bpf/prog_tests/task_local_storage.c +++ b/tools/testing/selftests/bpf/prog_tests/task_local_storage.c @@ -8,6 +8,7 @@ #include #include "task_local_storage.skel.h" #include "task_local_storage_exit_creds.skel.h" +#include "task_ls_recursion.skel.h" static void test_sys_enter_exit(void) { @@ -60,10 +61,32 @@ static void test_exit_creds(void) task_local_storage_exit_creds__destroy(skel); } +static void test_recursion(void) +{ + struct task_ls_recursion *skel; + int err; + + skel = task_ls_recursion__open_and_load(); + if (!ASSERT_OK_PTR(skel, "skel_open_and_load")) + return; + + err = task_ls_recursion__attach(skel); + if (!ASSERT_OK(err, "skel_attach")) + goto out; + + /* trigger sys_enter, make sure it does not cause deadlock */ + syscall(SYS_gettid); + +out: + task_ls_recursion__destroy(skel); +} + void test_task_local_storage(void) { if (test__start_subtest("sys_enter_exit")) test_sys_enter_exit(); if (test__start_subtest("exit_creds")) test_exit_creds(); + if (test__start_subtest("recursion")) + test_recursion(); } diff --git a/tools/testing/selftests/bpf/progs/task_ls_recursion.c b/tools/testing/selftests/bpf/progs/task_ls_recursion.c new file mode 100644 index 0000000000000..564583dca7c85 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/task_ls_recursion.c @@ -0,0 +1,70 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Facebook */ + +#include "vmlinux.h" +#include +#include + +char _license[] SEC("license") = "GPL"; + +struct { + __uint(type, BPF_MAP_TYPE_TASK_STORAGE); + __uint(map_flags, BPF_F_NO_PREALLOC); + __type(key, int); + __type(value, long); +} map_a SEC(".maps"); + +struct { + __uint(type, BPF_MAP_TYPE_TASK_STORAGE); + __uint(map_flags, BPF_F_NO_PREALLOC); + __type(key, int); + __type(value, long); +} map_b SEC(".maps"); + +SEC("fentry/bpf_local_storage_lookup") +int BPF_PROG(on_lookup) +{ + struct task_struct *task = bpf_get_current_task_btf(); + + bpf_task_storage_delete(&map_a, task); + bpf_task_storage_delete(&map_b, task); + return 0; +} + +SEC("fentry/bpf_local_storage_update") +int BPF_PROG(on_update) +{ + struct task_struct *task = bpf_get_current_task_btf(); + long *ptr; + + ptr = bpf_task_storage_get(&map_a, task, 0, + BPF_LOCAL_STORAGE_GET_F_CREATE); + if (ptr) + *ptr += 1; + + ptr = bpf_task_storage_get(&map_b, task, 0, + BPF_LOCAL_STORAGE_GET_F_CREATE); + if (ptr) + *ptr += 1; + + return 0; +} + +SEC("tp_btf/sys_enter") +int BPF_PROG(on_enter, struct pt_regs *regs, long id) +{ + struct task_struct *task; + long *ptr; + + task = bpf_get_current_task_btf(); + ptr = bpf_task_storage_get(&map_a, task, 0, + BPF_LOCAL_STORAGE_GET_F_CREATE); + if (ptr) + *ptr = 200; + + ptr = bpf_task_storage_get(&map_b, task, 0, + BPF_LOCAL_STORAGE_GET_F_CREATE); + if (ptr) + *ptr = 100; + return 0; +}