From patchwork Mon Nov 8 08:38:40 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yafang Shao X-Patchwork-Id: 12608025 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 649D8C433F5 for ; Mon, 8 Nov 2021 08:40:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4A61C61163 for ; Mon, 8 Nov 2021 08:40:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238252AbhKHInA (ORCPT ); Mon, 8 Nov 2021 03:43:00 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45744 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238172AbhKHImj (ORCPT ); Mon, 8 Nov 2021 03:42:39 -0500 Received: from mail-pj1-x102d.google.com (mail-pj1-x102d.google.com [IPv6:2607:f8b0:4864:20::102d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A57BBC061570; Mon, 8 Nov 2021 00:39:55 -0800 (PST) Received: by mail-pj1-x102d.google.com with SMTP id j5-20020a17090a318500b001a6c749e697so6128436pjb.1; Mon, 08 Nov 2021 00:39:55 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=yrH87tfprvHWh1UM/Pxd5vb7Nmf3wgq3PePQi/OQ3fM=; b=UXeJsykeaTS2gyNy6C+oQj/glOemNbibLh5K9uUAexVW98PENGloN1a1DQBKk79Sfz 97shWEXQKatj7t9wk3efdtyJuTylV/6D4GHU0LBtL4lvH3+9MqfldW+cxMZG7wHSw7Ty JLqnQNmZvMc9EnMjtW5gpgosJOELC0bm0xHfIqED/x296LBWnK2O39c5TcdIQL6syzJs lKYZXVvLw8Sof1pb9lqgZlUdGLs32Xc7bpwlrnX91/zOCUhNZuzGTihu/4zP+IG+9zvA kFLxPD0E7Jc0wFI8ssDHUG9vbV7+mB0nHoLZw5HfSgwe+1a4TqmO2ejzjJmLS2U3/+EK uUkw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=yrH87tfprvHWh1UM/Pxd5vb7Nmf3wgq3PePQi/OQ3fM=; b=Vr4hvQM2yvbPRMQXQfzxkWgT7toBVQxNKz8EZsCpRNMY4QUkQvFtUAbaKMnCkXqGsg f1PhSztDXhRdP9FH0Fq7PxzD/oqkvI2ZASVknaQ/MLgJnwtLJwyVrWziCF2gXwaT4do6 VR/gf1q3ox5ACZsPABJdkafQs5DleLuU361WGzufmrFpcNt7sRIetjivV2aK111UbSlk SOfJrTo8zoTqpRJ1CpaCIo8rNUdc1N5ZYMhrnJD/tYLxyIUB94iXCSed/nGu3yaFMrbx pnMlrOZeF3U0YQiWYJ7+2x3CG7erpKQ4GDvZxFXvHvjU420KQcf2Fq7zoM5WOV+Ov+aY 845w== X-Gm-Message-State: AOAM533wW/8Q0r3hoctqKEIM5AjJW3xeZABTdNxbqK9TFETMj4Dhp1MW ApKD4ieupJqHfKIfBsEASqI= X-Google-Smtp-Source: ABdhPJzwe6vL48ZC4bLnBtXKY3tyRaqx6od1EbhiMSxN08dDtV62OsE+sTwHtDjbGUZBdCwHWVvgzg== X-Received: by 2002:a17:90b:180d:: with SMTP id lw13mr38098294pjb.225.1636360795243; Mon, 08 Nov 2021 00:39:55 -0800 (PST) Received: from localhost.localdomain ([45.63.124.202]) by smtp.gmail.com with ESMTPSA id w3sm12253206pfd.195.2021.11.08.00.39.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 08 Nov 2021 00:39:54 -0800 (PST) From: Yafang Shao To: akpm@linux-foundation.org Cc: netdev@vger.kernel.org, bpf@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, oliver.sang@intel.com, lkp@intel.com, Yafang Shao , Andrii Nakryiko , Mathieu Desnoyers , Arnaldo Carvalho de Melo , Andrii Nakryiko , Michal Miroslaw , Peter Zijlstra , Steven Rostedt , Matthew Wilcox , David Hildenbrand , Al Viro , Kees Cook , Petr Mladek Subject: [PATCH 7/7] tools/testing/selftests/bpf: make it adopt to task comm size change Date: Mon, 8 Nov 2021 08:38:40 +0000 Message-Id: <20211108083840.4627-8-laoar.shao@gmail.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20211108083840.4627-1-laoar.shao@gmail.com> References: <20211108083840.4627-1-laoar.shao@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net The hard-coded 16 is used in various bpf progs. These progs get task comm either via bpf_get_current_comm() or prctl() or bpf_core_read_str(), all of which can work well even if the task comm size is changed. In these BPF programs, one thing to be improved is the sched:sched_switch tracepoint args. As the tracepoint args are derived from the kernel, we'd better make it same with the kernel. So the macro TASK_COMM_LEN is converted to type enum, then all the BPF programs can get it through BTF. The BPF program which wants to use TASK_COMM_LEN should include the header vmlinux.h. Regarding the test_stacktrace_map and test_tracepoint, as the type defined in linux/bpf.h are also defined in vmlinux.h, so we don't need to include linux/bpf.h again. Signed-off-by: Yafang Shao Acked-by: Andrii Nakryiko Cc: Mathieu Desnoyers Cc: Arnaldo Carvalho de Melo Cc: Andrii Nakryiko Cc: Michal Miroslaw Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Matthew Wilcox Cc: David Hildenbrand Cc: Al Viro Cc: Kees Cook Cc: Petr Mladek Acked-by: David Hildenbrand --- include/linux/sched.h | 9 +++++++-- tools/testing/selftests/bpf/progs/test_stacktrace_map.c | 6 +++--- tools/testing/selftests/bpf/progs/test_tracepoint.c | 6 +++--- 3 files changed, 13 insertions(+), 8 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index e0454e60fe8f..1c456691f890 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -274,8 +274,13 @@ struct task_group; #define get_current_state() READ_ONCE(current->__state) -/* Task command name length: */ -#define TASK_COMM_LEN 16 +/* + * Define the task command name length as enum, then it can be visible to + * BPF programs. + */ +enum { + TASK_COMM_LEN = 16, +}; extern void scheduler_tick(void); diff --git a/tools/testing/selftests/bpf/progs/test_stacktrace_map.c b/tools/testing/selftests/bpf/progs/test_stacktrace_map.c index 00ed48672620..e9b602a6dc1b 100644 --- a/tools/testing/selftests/bpf/progs/test_stacktrace_map.c +++ b/tools/testing/selftests/bpf/progs/test_stacktrace_map.c @@ -1,7 +1,7 @@ // SPDX-License-Identifier: GPL-2.0 // Copyright (c) 2018 Facebook -#include +#include #include #ifndef PERF_MAX_STACK_DEPTH @@ -41,11 +41,11 @@ struct { /* taken from /sys/kernel/debug/tracing/events/sched/sched_switch/format */ struct sched_switch_args { unsigned long long pad; - char prev_comm[16]; + char prev_comm[TASK_COMM_LEN]; int prev_pid; int prev_prio; long long prev_state; - char next_comm[16]; + char next_comm[TASK_COMM_LEN]; int next_pid; int next_prio; }; diff --git a/tools/testing/selftests/bpf/progs/test_tracepoint.c b/tools/testing/selftests/bpf/progs/test_tracepoint.c index 4b825ee122cf..f21982681e28 100644 --- a/tools/testing/selftests/bpf/progs/test_tracepoint.c +++ b/tools/testing/selftests/bpf/progs/test_tracepoint.c @@ -1,17 +1,17 @@ // SPDX-License-Identifier: GPL-2.0 // Copyright (c) 2017 Facebook -#include +#include #include /* taken from /sys/kernel/debug/tracing/events/sched/sched_switch/format */ struct sched_switch_args { unsigned long long pad; - char prev_comm[16]; + char prev_comm[TASK_COMM_LEN]; int prev_pid; int prev_prio; long long prev_state; - char next_comm[16]; + char next_comm[TASK_COMM_LEN]; int next_pid; int next_prio; };