From patchwork Thu Mar 16 05:40:26 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Vernet X-Patchwork-Id: 13177005 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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 15E92C6FD1F for ; Thu, 16 Mar 2023 05:40:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229830AbjCPFkq (ORCPT ); Thu, 16 Mar 2023 01:40:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47218 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229802AbjCPFkm (ORCPT ); Thu, 16 Mar 2023 01:40:42 -0400 Received: from mail-qt1-f175.google.com (mail-qt1-f175.google.com [209.85.160.175]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1CAA75F21D; Wed, 15 Mar 2023 22:40:40 -0700 (PDT) Received: by mail-qt1-f175.google.com with SMTP id t9so630315qtx.8; Wed, 15 Mar 2023 22:40:40 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1678945239; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=fa2fhlw1TqFXS4nJVOwTl5oF6HLkgTrJ78c4jwZcDqU=; b=J1aGYm4XpzzJNzoci0JgQFAA5Yb5hgQwylVi/6HvBAnpI72YsuZj3CumC2gNQm7cwu qDlCeZi4h7DgNg9vNEY+5Fm9A3bxJGAK3WcKjeWOmwzCACg/Kmj5VWzuddxLwZDKf8zZ 885sIOorIvcz8K1Bp7zoCtI+ziyP5C1zu0zrqQOJlML1mSDDXzhVbnAZrXf6WLNdinVa 5Ubu7oWm1v5n44Y2SXIeDlsunluOFEzeFBtSpTVuwLawJoIz5kgBPjIzgqY4gGkg+MPC xkn9zJlYfWeXMyT2gH3kpp9NLApSuvJWPLAFpVQLDBHbRlnbo4EI+Fd0VS53rvAWTI/B Mgog== X-Gm-Message-State: AO0yUKU1BwDviIYwGrE1RerHzSLnW24zIJl3Jk362HmGNNCGq9LitiG+ D/AmzUMZ/Kppe0mLu9/c4ODDr66Ivzqi1JGD X-Google-Smtp-Source: AK7set+rZ9Aply+gc6/6dEFQe9Yi92wuLTMOtrpEXExmliE4f0Rsh6NZRkibpaiPeVAVFtxP2d+kgw== X-Received: by 2002:a05:622a:174c:b0:3bf:db29:b793 with SMTP id l12-20020a05622a174c00b003bfdb29b793mr4696811qtk.20.1678945239228; Wed, 15 Mar 2023 22:40:39 -0700 (PDT) Received: from localhost ([2620:10d:c091:400::5:7f57]) by smtp.gmail.com with ESMTPSA id d192-20020ae9efc9000000b00745df1fac2bsm3876535qkg.76.2023.03.15.22.40.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 Mar 2023 22:40:38 -0700 (PDT) From: David Vernet To: bpf@vger.kernel.org Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, martin.lau@linux.dev, song@kernel.org, yhs@fb.com, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@google.com, haoluo@google.com, jolsa@kernel.org, linux-kernel@vger.kernel.org, kernel-team@meta.com Subject: [PATCH bpf-next v2 3/5] bpf/selftests: Test using global cpumask kptr with RCU Date: Thu, 16 Mar 2023 00:40:26 -0500 Message-Id: <20230316054028.88924-4-void@manifault.com> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20230316054028.88924-1-void@manifault.com> References: <20230316054028.88924-1-void@manifault.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Now that struct bpf_cpumask * is considered an RCU-safe type according to the verifier, we should add tests that validate its common usages. This patch adds those tests to the cpumask test suite. A subsequent changes will remove bpf_cpumask_kptr_get(), and will adjust the selftest and BPF documentation accordingly. Signed-off-by: David Vernet --- .../selftests/bpf/prog_tests/cpumask.c | 1 + .../selftests/bpf/progs/cpumask_common.h | 6 ++ .../selftests/bpf/progs/cpumask_failure.c | 62 +++++++++++++++++++ .../selftests/bpf/progs/cpumask_success.c | 33 ++++++++++ 4 files changed, 102 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/cpumask.c b/tools/testing/selftests/bpf/prog_tests/cpumask.c index 5fbe457c4ebe..6c0fe23498c7 100644 --- a/tools/testing/selftests/bpf/prog_tests/cpumask.c +++ b/tools/testing/selftests/bpf/prog_tests/cpumask.c @@ -17,6 +17,7 @@ static const char * const cpumask_success_testcases[] = { "test_insert_leave", "test_insert_remove_release", "test_insert_kptr_get_release", + "test_global_mask_rcu", }; static void verify_success(const char *prog_name) diff --git a/tools/testing/selftests/bpf/progs/cpumask_common.h b/tools/testing/selftests/bpf/progs/cpumask_common.h index 65e5496ca1b2..7623782fbd62 100644 --- a/tools/testing/selftests/bpf/progs/cpumask_common.h +++ b/tools/testing/selftests/bpf/progs/cpumask_common.h @@ -9,6 +9,9 @@ int err; +#define private(name) SEC(".bss." #name) __hidden __attribute__((aligned(8))) +private(MASK) static struct bpf_cpumask __kptr * global_mask; + struct __cpumask_map_value { struct bpf_cpumask __kptr * cpumask; }; @@ -51,6 +54,9 @@ void bpf_cpumask_copy(struct bpf_cpumask *dst, const struct cpumask *src) __ksym u32 bpf_cpumask_any(const struct cpumask *src) __ksym; u32 bpf_cpumask_any_and(const struct cpumask *src1, const struct cpumask *src2) __ksym; +void bpf_rcu_read_lock(void) __ksym; +void bpf_rcu_read_unlock(void) __ksym; + static inline const struct cpumask *cast(struct bpf_cpumask *cpumask) { return (const struct cpumask *)cpumask; diff --git a/tools/testing/selftests/bpf/progs/cpumask_failure.c b/tools/testing/selftests/bpf/progs/cpumask_failure.c index cfe83f0ef9e2..9f726d55f747 100644 --- a/tools/testing/selftests/bpf/progs/cpumask_failure.c +++ b/tools/testing/selftests/bpf/progs/cpumask_failure.c @@ -127,3 +127,65 @@ int BPF_PROG(test_cpumask_null, struct task_struct *task, u64 clone_flags) return 0; } + +SEC("tp_btf/task_newtask") +__failure __msg("R2 must be a rcu pointer") +int BPF_PROG(test_global_mask_out_of_rcu, struct task_struct *task, u64 clone_flags) +{ + struct bpf_cpumask *local, *prev; + + local = create_cpumask(); + if (!local) + return 0; + + prev = bpf_kptr_xchg(&global_mask, local); + if (prev) { + bpf_cpumask_release(prev); + err = 3; + return 0; + } + + bpf_rcu_read_lock(); + local = global_mask; + if (!local) { + err = 4; + bpf_rcu_read_unlock(); + return 0; + } + + bpf_rcu_read_unlock(); + + /* RCU region is exited before calling KF_RCU kfunc. */ + + bpf_cpumask_test_cpu(0, (const struct cpumask *)local); + + return 0; +} + +SEC("tp_btf/task_newtask") +__failure __msg("NULL pointer passed to trusted arg1") +int BPF_PROG(test_global_mask_no_null_check, struct task_struct *task, u64 clone_flags) +{ + struct bpf_cpumask *local, *prev; + + local = create_cpumask(); + if (!local) + return 0; + + prev = bpf_kptr_xchg(&global_mask, local); + if (prev) { + bpf_cpumask_release(prev); + err = 3; + return 0; + } + + bpf_rcu_read_lock(); + local = global_mask; + + /* No NULL check is performed on global cpumask kptr. */ + bpf_cpumask_test_cpu(0, (const struct cpumask *)local); + + bpf_rcu_read_unlock(); + + return 0; +} diff --git a/tools/testing/selftests/bpf/progs/cpumask_success.c b/tools/testing/selftests/bpf/progs/cpumask_success.c index 97ed08c4ff03..fe928ff72a06 100644 --- a/tools/testing/selftests/bpf/progs/cpumask_success.c +++ b/tools/testing/selftests/bpf/progs/cpumask_success.c @@ -423,3 +423,36 @@ int BPF_PROG(test_insert_kptr_get_release, struct task_struct *task, u64 clone_f return 0; } + +SEC("tp_btf/task_newtask") +int BPF_PROG(test_global_mask_rcu, struct task_struct *task, u64 clone_flags) +{ + struct bpf_cpumask *local, *prev; + + if (!is_test_task()) + return 0; + + local = create_cpumask(); + if (!local) + return 0; + + prev = bpf_kptr_xchg(&global_mask, local); + if (prev) { + bpf_cpumask_release(prev); + err = 3; + return 0; + } + + bpf_rcu_read_lock(); + local = global_mask; + if (!local) { + err = 4; + bpf_rcu_read_unlock(); + return 0; + } + + bpf_cpumask_test_cpu(0, (const struct cpumask *)local); + bpf_rcu_read_unlock(); + + return 0; +}