From patchwork Mon Oct 9 16:14:13 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Vernet X-Patchwork-Id: 13414002 X-Patchwork-Delegate: bpf@iogearbox.net Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 97CF338BA8 for ; Mon, 9 Oct 2023 16:14:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=none Received: from mail-il1-f176.google.com (mail-il1-f176.google.com [209.85.166.176]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3B222D8; Mon, 9 Oct 2023 09:14:21 -0700 (PDT) Received: by mail-il1-f176.google.com with SMTP id e9e14a558f8ab-3526c9c401aso15576715ab.1; Mon, 09 Oct 2023 09:14:21 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1696868061; x=1697472861; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=2oz2+J9eLTjHyn4qVA1tue5CmqKBSnkz6z7OJvEmTc0=; b=kHJhqvPwQU6jb5ZG0u1Az33HdKVJyFPDl5jiBUDtAUctOpU6Jq5UJLyj+uSJIHfTpg TJC9B8pITZ/qez3Y155oz6T/gZsMVmqyoqcJwp1JUc9wM/QwRKIxty8YSRAMhmqS2+yi n8xD7p1tt7vCsfaf65uTxJpf6MhS0zeyAHCd67inSxrUegE06eo3zSBKA5u7jhGUPt7U nXMEmiqyTePqtgKFEmPGzeKvvtOV/QmbPI727HN1/N0M2degSmvAe/F6XqEoEyOCP+sv JcmTjgwWIoKDTkGNxhPvm3bdlusmJixVyLefcRDfJUcTeo2tS66GU/Cchps2NTy/lDgj SXPA== X-Gm-Message-State: AOJu0YzOHUPWQ86RwQlU93Ca7+h2ilYaX7ZvtATiuCxy0RqlKCI9I9lq nT402+haGDiB0kt+dl5E+kPB1pfZ78R4Aqit X-Google-Smtp-Source: AGHT+IEPd5aeYH+JcNEYASnuKN/+aGbFmVjrwPIXtxlZDhvg9/Wu+bU96dcz1arMg7m9ai4g/l2/gw== X-Received: by 2002:a05:6e02:178f:b0:350:f0e6:a7c5 with SMTP id y15-20020a056e02178f00b00350f0e6a7c5mr10686419ilu.16.1696868060761; Mon, 09 Oct 2023 09:14:20 -0700 (PDT) Received: from localhost (c-24-1-27-177.hsd1.il.comcast.net. [24.1.27.177]) by smtp.gmail.com with ESMTPSA id dp19-20020a0566381c9300b0043a1a45a7b2sm2208240jab.62.2023.10.09.09.14.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 09 Oct 2023 09:14:20 -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, yonghong.song@linux.dev, 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 1/2] bpf: Fix verifier log for async callback return values Date: Mon, 9 Oct 2023 11:14:13 -0500 Message-ID: <20231009161414.235829-1-void@manifault.com> X-Mailer: git-send-email 2.41.0 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam-Status: No, score=-1.4 required=5.0 tests=BAYES_00, FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS, RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-Delegate: bpf@iogearbox.net The verifier, as part of check_return_code(), verifies that async callbacks such as from e.g. timers, will return 0. It does this by correctly checking that R0->var_off is in tnum_const(0), which effectively checks that it's in a range of 0. If this condition fails, however, it prints an error message which says that the value should have been in (0x0; 0x1). This results in possibly confusing output such as the following in which an async callback returns 1: At async callback the register R0 has value (0x1; 0x0) should have been in (0x0; 0x1) The fix is easy -- we should just pass the tnum_const(0) as the correct range to verbose_invalid_scalar(), which will then print the following: At async callback the register R0 has value (0x1; 0x0) should have been in (0x0; 0x0) Fixes: bfc6bb74e4f1 ("bpf: Implement verifier support for validation of async callbacks.") Signed-off-by: David Vernet --- kernel/bpf/verifier.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index eed7350e15f4..9093fb74c88e 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -14729,7 +14729,7 @@ static int check_return_code(struct bpf_verifier_env *env, int regno) struct tnum enforce_attach_type_range = tnum_unknown; const struct bpf_prog *prog = env->prog; struct bpf_reg_state *reg; - struct tnum range = tnum_range(0, 1); + struct tnum range = tnum_range(0, 1), const_0 = tnum_const(0); enum bpf_prog_type prog_type = resolve_prog_type(env->prog); int err; struct bpf_func_state *frame = env->cur_state->frame[0]; @@ -14777,8 +14777,8 @@ static int check_return_code(struct bpf_verifier_env *env, int regno) return -EINVAL; } - if (!tnum_in(tnum_const(0), reg->var_off)) { - verbose_invalid_scalar(env, reg, &range, "async callback", "R0"); + if (!tnum_in(const_0, reg->var_off)) { + verbose_invalid_scalar(env, reg, &const_0, "async callback", "R0"); return -EINVAL; } return 0; From patchwork Mon Oct 9 16:14:14 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Vernet X-Patchwork-Id: 13414001 X-Patchwork-Delegate: bpf@iogearbox.net Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9017135887 for ; Mon, 9 Oct 2023 16:14:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=none Received: from mail-il1-f180.google.com (mail-il1-f180.google.com [209.85.166.180]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2112CDB; Mon, 9 Oct 2023 09:14:23 -0700 (PDT) Received: by mail-il1-f180.google.com with SMTP id e9e14a558f8ab-352a3a95271so18231295ab.0; Mon, 09 Oct 2023 09:14:23 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1696868062; x=1697472862; 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=Nn/6KVXbliEOh9rFCg0BPlbCxwqo18KGwCNTlkH9z2s=; b=ayXOAaNREBHp/zziISJHyEOiUq944jCcZYLXpCblWqKsEyUwScwxcL3XizWB85YfxQ HduAgQV1IzaIe/o73NHwWnPELg5lU46glo7yYqXlzK6Xf0PxsuLdrxPai9NtFdVhehPb VMCpCtGlKRZSAIIrhNn48F57lE8BIrGrBOGZWa/a2GHyUmRHoQQBUpxoh8iTFcKff/in bYP4+9a4muWwCbU9Ufm3v7ZxbEmwyLoyicFUWfI93Brvkx/Ar7Ye8JEGtguxb/NKTc73 Qqz/b8D5etdi0qMwwF3IzvjOF6OHnMmbt/c3qyBlzW35FWJHCrc4YUpFyDnKORzJxbZf 0HJw== X-Gm-Message-State: AOJu0YxA+M+Fq/zNqkCnRChYw9ess8h/6NeOG2axpV1bldrdo1xb9Ih0 Lk1mWpNSzZsuz4lhs/uG1AI5m41qZ4r6LD0G X-Google-Smtp-Source: AGHT+IFwy8aDUIVX5U7FdjzcvhTMzgvv/VgiEcL550rclKOOP1rK8SASnDN56t9rY9oCbs/egGYSAw== X-Received: by 2002:a92:c262:0:b0:34c:cf1f:2a4a with SMTP id h2-20020a92c262000000b0034ccf1f2a4amr19831982ild.4.1696868062029; Mon, 09 Oct 2023 09:14:22 -0700 (PDT) Received: from localhost (c-24-1-27-177.hsd1.il.comcast.net. [24.1.27.177]) by smtp.gmail.com with ESMTPSA id q2-20020a056e02078200b0035163fb9f9fsm2999771ils.43.2023.10.09.09.14.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 09 Oct 2023 09:14:21 -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, yonghong.song@linux.dev, 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 2/2] bpf/selftests: Add testcase for async callback return value failure Date: Mon, 9 Oct 2023 11:14:14 -0500 Message-ID: <20231009161414.235829-2-void@manifault.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20231009161414.235829-1-void@manifault.com> References: <20231009161414.235829-1-void@manifault.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam-Status: No, score=-1.4 required=5.0 tests=BAYES_00, FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS, RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-Delegate: bpf@iogearbox.net A previous commit updated the verifier to print an accurate failure message for when someone specifies a nonzero return value from an async callback. This adds a testcase for validating that the verifier emits the correct message in such a case. Signed-off-by: David Vernet --- .../testing/selftests/bpf/prog_tests/timer.c | 6 ++- .../selftests/bpf/progs/timer_failure.c | 47 +++++++++++++++++++ 2 files changed, 51 insertions(+), 2 deletions(-) create mode 100644 tools/testing/selftests/bpf/progs/timer_failure.c diff --git a/tools/testing/selftests/bpf/prog_tests/timer.c b/tools/testing/selftests/bpf/prog_tests/timer.c index d8bc838445ec..760ad96b4be0 100644 --- a/tools/testing/selftests/bpf/prog_tests/timer.c +++ b/tools/testing/selftests/bpf/prog_tests/timer.c @@ -2,6 +2,7 @@ /* Copyright (c) 2021 Facebook */ #include #include "timer.skel.h" +#include "timer_failure.skel.h" static int timer(struct timer *timer_skel) { @@ -53,10 +54,11 @@ void serial_test_timer(void) timer_skel = timer__open_and_load(); if (!ASSERT_OK_PTR(timer_skel, "timer_skel_load")) - goto cleanup; + return; err = timer(timer_skel); ASSERT_OK(err, "timer"); -cleanup: timer__destroy(timer_skel); + + RUN_TESTS(timer_failure); } diff --git a/tools/testing/selftests/bpf/progs/timer_failure.c b/tools/testing/selftests/bpf/progs/timer_failure.c new file mode 100644 index 000000000000..226d33b5a05c --- /dev/null +++ b/tools/testing/selftests/bpf/progs/timer_failure.c @@ -0,0 +1,47 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */ + +#include +#include +#include +#include +#include "bpf_misc.h" +#include "bpf_tcp_helpers.h" + +char _license[] SEC("license") = "GPL"; + +struct elem { + struct bpf_timer t; +}; + +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __uint(max_entries, 1); + __type(key, int); + __type(value, struct elem); +} timer_map SEC(".maps"); + +static int timer_cb_ret1(void *map, int *key, struct bpf_timer *timer) +{ + if (bpf_get_smp_processor_id() % 2) + return 1; + else + return 0; +} + +SEC("fentry/bpf_fentry_test1") +__failure __msg("should have been in (0x0; 0x0)") +int BPF_PROG2(test_ret_1, int, a) +{ + int key = 0; + struct bpf_timer *timer; + + timer = bpf_map_lookup_elem(&timer_map, &key); + if (timer) { + bpf_timer_init(timer, &timer_map, CLOCK_BOOTTIME); + bpf_timer_set_callback(timer, timer_cb_ret1); + bpf_timer_start(timer, 1000, 0); + } + + return 0; +}