From patchwork Sun Apr 16 08:49:26 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Vernet X-Patchwork-Id: 13212736 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 5AD85C77B72 for ; Sun, 16 Apr 2023 08:49:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230184AbjDPItk (ORCPT ); Sun, 16 Apr 2023 04:49:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58570 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229976AbjDPItj (ORCPT ); Sun, 16 Apr 2023 04:49:39 -0400 Received: from mail-qv1-f53.google.com (mail-qv1-f53.google.com [209.85.219.53]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 52CB3106; Sun, 16 Apr 2023 01:49:38 -0700 (PDT) Received: by mail-qv1-f53.google.com with SMTP id qh25so12361541qvb.1; Sun, 16 Apr 2023 01:49:38 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1681634977; x=1684226977; 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=bf8/DhXyxhQVxCLkoC9tNfxIfJDkgAT+2/+mmZzl0Og=; b=ckLo63LLv3aC872kK+l7PHvn16dsLcSt5FzZ5LHtFhEpCHLQqJ8m0Yek7lWlrUxKlO yLtdQ5/dRJNL6KsOZNFfe2OszMrnOZXuJ9oWHdEYwLpZBu2k6oToEeLKeNeOLADLACkI VpsrTY2eIkj+kzu+UHzHt+SrY3jfMmPmgTBuwF1w/vteg62fy40tmEgVXqDf1QRjtXF7 lPLlBX1yiiAtqIH8JlCIdWd20m3AMOauukbOSqPDGabLblpIKxuxoRsTd0Xs6vfrQcgN /qU+hbT/LPWfQBpqndxZCFjm80dVM8Q380rpfIQuZxlsdnyq7DkCMmljbbhbOHiXCya0 zv8g== X-Gm-Message-State: AAQBX9ej0JaJBNz1hviSb3IyCgft37sh7Ssad8Fu9jh8ASGb8i7rkcHH G11nYHQJm5zIyN9YrjvmZTSWX8hIkCkruQcE4YXDZg== X-Google-Smtp-Source: AKy350YkDXYDeTE1tPQM4QuNTo3oOLWXHxs8/nddkF4/XRhDcd7uRJUgO2tBH7420HK5vj9e/zZb2g== X-Received: by 2002:a05:6214:5090:b0:5ef:67b9:8d37 with SMTP id kk16-20020a056214509000b005ef67b98d37mr4173633qvb.13.1681634976964; Sun, 16 Apr 2023 01:49:36 -0700 (PDT) Received: from localhost ([24.1.27.177]) by smtp.gmail.com with ESMTPSA id s14-20020ad44b2e000000b005eee5c22f30sm2298803qvw.139.2023.04.16.01.49.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 16 Apr 2023 01:49:36 -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, memxor@gmail.com Subject: [PATCH bpf-next v2 1/3] bpf: Remove bpf_kfunc_call_test_kptr_get() test kfunc Date: Sun, 16 Apr 2023 03:49:26 -0500 Message-Id: <20230416084928.326135-2-void@manifault.com> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230416084928.326135-1-void@manifault.com> References: <20230416084928.326135-1-void@manifault.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net We've managed to improve the UX for kptrs significantly over the last 9 months. All of the prior main use cases, struct bpf_cpumask *, struct task_struct *, and struct cgroup *, have all been updated to be synchronized mainly using RCU. In other words, their KF_ACQUIRE kfunc calls are all KF_RCU, and the pointers themselves are MEM_RCU and can be accessed in an RCU read region in BPF. In a follow-on change, we'll be removing the KF_KPTR_GET kfunc flag. This patch prepares for that by removing the bpf_kfunc_call_test_kptr_get() kfunc, and all associated selftests. Signed-off-by: David Vernet --- net/bpf/test_run.c | 12 --- tools/testing/selftests/bpf/progs/map_kptr.c | 40 ++-------- .../selftests/bpf/progs/map_kptr_fail.c | 78 ------------------- .../testing/selftests/bpf/verifier/map_kptr.c | 27 ------- 4 files changed, 5 insertions(+), 152 deletions(-) diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c index 0b9bd9b39990..f170e8a17974 100644 --- a/net/bpf/test_run.c +++ b/net/bpf/test_run.c @@ -679,17 +679,6 @@ __bpf_kfunc void bpf_kfunc_call_int_mem_release(int *p) { } -__bpf_kfunc struct prog_test_ref_kfunc * -bpf_kfunc_call_test_kptr_get(struct prog_test_ref_kfunc **pp, int a, int b) -{ - struct prog_test_ref_kfunc *p = READ_ONCE(*pp); - - if (!p) - return NULL; - refcount_inc(&p->cnt); - return p; -} - struct prog_test_pass1 { int x0; struct { @@ -804,7 +793,6 @@ BTF_ID_FLAGS(func, bpf_kfunc_call_test_get_rdwr_mem, KF_RET_NULL) BTF_ID_FLAGS(func, bpf_kfunc_call_test_get_rdonly_mem, KF_RET_NULL) BTF_ID_FLAGS(func, bpf_kfunc_call_test_acq_rdonly_mem, KF_ACQUIRE | KF_RET_NULL) BTF_ID_FLAGS(func, bpf_kfunc_call_int_mem_release, KF_RELEASE) -BTF_ID_FLAGS(func, bpf_kfunc_call_test_kptr_get, KF_ACQUIRE | KF_RET_NULL | KF_KPTR_GET) BTF_ID_FLAGS(func, bpf_kfunc_call_test_pass_ctx) BTF_ID_FLAGS(func, bpf_kfunc_call_test_pass1) BTF_ID_FLAGS(func, bpf_kfunc_call_test_pass2) diff --git a/tools/testing/selftests/bpf/progs/map_kptr.c b/tools/testing/selftests/bpf/progs/map_kptr.c index dae5dab1bbf7..d7150041e5d1 100644 --- a/tools/testing/selftests/bpf/progs/map_kptr.c +++ b/tools/testing/selftests/bpf/progs/map_kptr.c @@ -115,8 +115,6 @@ DEFINE_MAP_OF_MAP(BPF_MAP_TYPE_HASH_OF_MAPS, hash_malloc_map, hash_of_hash_mallo DEFINE_MAP_OF_MAP(BPF_MAP_TYPE_HASH_OF_MAPS, lru_hash_map, hash_of_lru_hash_maps); extern struct prog_test_ref_kfunc *bpf_kfunc_call_test_acquire(unsigned long *sp) __ksym; -extern struct prog_test_ref_kfunc * -bpf_kfunc_call_test_kptr_get(struct prog_test_ref_kfunc **p, int a, int b) __ksym; extern void bpf_kfunc_call_test_release(struct prog_test_ref_kfunc *p) __ksym; void bpf_kfunc_call_test_ref(struct prog_test_ref_kfunc *p) __ksym; @@ -187,25 +185,10 @@ static void test_kptr_ref(struct map_value *v) bpf_kfunc_call_test_release(p); } -static void test_kptr_get(struct map_value *v) -{ - struct prog_test_ref_kfunc *p; - - p = bpf_kfunc_call_test_kptr_get(&v->ref_ptr, 0, 0); - if (!p) - return; - if (p->a + p->b > 100) { - bpf_kfunc_call_test_release(p); - return; - } - bpf_kfunc_call_test_release(p); -} - static void test_kptr(struct map_value *v) { test_kptr_unref(v); test_kptr_ref(v); - test_kptr_get(v); } SEC("tc") @@ -338,38 +321,25 @@ int test_map_kptr_ref_pre(struct map_value *v) if (p_st->cnt.refs.counter != ref) return 4; - p = bpf_kfunc_call_test_kptr_get(&v->ref_ptr, 0, 0); - if (!p) - return 5; - ref++; - if (p_st->cnt.refs.counter != ref) { - ret = 6; - goto end; - } - bpf_kfunc_call_test_release(p); - ref--; - if (p_st->cnt.refs.counter != ref) - return 7; - p = bpf_kptr_xchg(&v->ref_ptr, NULL); if (!p) - return 8; + return 5; bpf_kfunc_call_test_release(p); ref--; if (p_st->cnt.refs.counter != ref) - return 9; + return 6; p = bpf_kfunc_call_test_acquire(&arg); if (!p) - return 10; + return 7; ref++; p = bpf_kptr_xchg(&v->ref_ptr, p); if (p) { - ret = 11; + ret = 8; goto end; } if (p_st->cnt.refs.counter != ref) - return 12; + return 9; /* Leave in map */ return 0; diff --git a/tools/testing/selftests/bpf/progs/map_kptr_fail.c b/tools/testing/selftests/bpf/progs/map_kptr_fail.c index 15bf3127dba3..da8c724f839b 100644 --- a/tools/testing/selftests/bpf/progs/map_kptr_fail.c +++ b/tools/testing/selftests/bpf/progs/map_kptr_fail.c @@ -21,8 +21,6 @@ struct array_map { extern struct prog_test_ref_kfunc *bpf_kfunc_call_test_acquire(unsigned long *sp) __ksym; extern void bpf_kfunc_call_test_release(struct prog_test_ref_kfunc *p) __ksym; -extern struct prog_test_ref_kfunc * -bpf_kfunc_call_test_kptr_get(struct prog_test_ref_kfunc **p, int a, int b) __ksym; SEC("?tc") __failure __msg("kptr access size must be BPF_DW") @@ -220,67 +218,6 @@ int reject_kptr_xchg_on_unref(struct __sk_buff *ctx) return 0; } -SEC("?tc") -__failure __msg("arg#0 expected pointer to map value") -int reject_kptr_get_no_map_val(struct __sk_buff *ctx) -{ - bpf_kfunc_call_test_kptr_get((void *)&ctx, 0, 0); - return 0; -} - -SEC("?tc") -__failure __msg("arg#0 expected pointer to map value") -int reject_kptr_get_no_null_map_val(struct __sk_buff *ctx) -{ - bpf_kfunc_call_test_kptr_get(bpf_map_lookup_elem(&array_map, &(int){0}), 0, 0); - return 0; -} - -SEC("?tc") -__failure __msg("arg#0 no referenced kptr at map value offset=0") -int reject_kptr_get_no_kptr(struct __sk_buff *ctx) -{ - struct map_value *v; - int key = 0; - - v = bpf_map_lookup_elem(&array_map, &key); - if (!v) - return 0; - - bpf_kfunc_call_test_kptr_get((void *)v, 0, 0); - return 0; -} - -SEC("?tc") -__failure __msg("arg#0 no referenced kptr at map value offset=8") -int reject_kptr_get_on_unref(struct __sk_buff *ctx) -{ - struct map_value *v; - int key = 0; - - v = bpf_map_lookup_elem(&array_map, &key); - if (!v) - return 0; - - bpf_kfunc_call_test_kptr_get(&v->unref_ptr, 0, 0); - return 0; -} - -SEC("?tc") -__failure __msg("kernel function bpf_kfunc_call_test_kptr_get args#0") -int reject_kptr_get_bad_type_match(struct __sk_buff *ctx) -{ - struct map_value *v; - int key = 0; - - v = bpf_map_lookup_elem(&array_map, &key); - if (!v) - return 0; - - bpf_kfunc_call_test_kptr_get((void *)&v->ref_memb_ptr, 0, 0); - return 0; -} - SEC("?tc") __failure __msg("R1 type=rcu_ptr_or_null_ expected=percpu_ptr_") int mark_ref_as_untrusted_or_null(struct __sk_buff *ctx) @@ -428,21 +365,6 @@ int kptr_xchg_ref_state(struct __sk_buff *ctx) return 0; } -SEC("?tc") -__failure __msg("Unreleased reference id=3 alloc_insn=") -int kptr_get_ref_state(struct __sk_buff *ctx) -{ - struct map_value *v; - int key = 0; - - v = bpf_map_lookup_elem(&array_map, &key); - if (!v) - return 0; - - bpf_kfunc_call_test_kptr_get(&v->ref_ptr, 0, 0); - return 0; -} - SEC("?tc") __failure __msg("Possibly NULL pointer passed to helper arg2") int kptr_xchg_possibly_null(struct __sk_buff *ctx) diff --git a/tools/testing/selftests/bpf/verifier/map_kptr.c b/tools/testing/selftests/bpf/verifier/map_kptr.c index d775ccb01989..a0cfc06d75bc 100644 --- a/tools/testing/selftests/bpf/verifier/map_kptr.c +++ b/tools/testing/selftests/bpf/verifier/map_kptr.c @@ -288,33 +288,6 @@ .result = REJECT, .errstr = "off=0 kptr isn't referenced kptr", }, -{ - "map_kptr: unref: bpf_kfunc_call_test_kptr_get rejected", - .insns = { - BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), - BPF_LD_MAP_FD(BPF_REG_6, 0), - BPF_MOV64_REG(BPF_REG_1, BPF_REG_6), - BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4), - BPF_MOV64_IMM(BPF_REG_0, 0), - BPF_ST_MEM(BPF_W, BPF_REG_2, 0, 0), - BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem), - BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1), - BPF_EXIT_INSN(), - BPF_MOV64_REG(BPF_REG_1, BPF_REG_0), - BPF_MOV64_IMM(BPF_REG_2, 0), - BPF_MOV64_IMM(BPF_REG_3, 0), - BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0), - BPF_MOV64_IMM(BPF_REG_0, 0), - BPF_EXIT_INSN(), - }, - .prog_type = BPF_PROG_TYPE_SCHED_CLS, - .fixup_map_kptr = { 1 }, - .result = REJECT, - .errstr = "arg#0 no referenced kptr at map value offset=0", - .fixup_kfunc_btf_id = { - { "bpf_kfunc_call_test_kptr_get", 13 }, - } -}, /* Tests for referenced PTR_TO_BTF_ID */ { "map_kptr: ref: loaded pointer marked as untrusted",