From mboxrd@z Thu Jan 1 00:00:00 1970 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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 AC0E0C33CA4 for ; Fri, 10 Jan 2020 20:35:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 815B2205F4 for ; Fri, 10 Jan 2020 20:35:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578688554; bh=Bix0dUf7a7fsuKuY6E6H+bdNW+apm7NX4GXgPTHh/wM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:In-Reply-To: References:List-ID:From; b=ceDQhskP8boDniU3CZgDtePizG/GnhUcYdbP4wmCihZ/pL31TgLJU0PSIj2uE1S4L Y7KQsr++kqJvDd2vReXUuZ+w0bmlF71O08gbZ8MSehXyZ0k36inYszf9UKImsGNpWU lHtJE7HaNJYht6IVrSmr3OdsNayiQqBqMfSqk6ek= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727446AbgAJUfx (ORCPT ); Fri, 10 Jan 2020 15:35:53 -0500 Received: from mail.kernel.org ([198.145.29.99]:58652 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727261AbgAJUfl (ORCPT ); Fri, 10 Jan 2020 15:35:41 -0500 Received: from localhost.localdomain (c-98-220-238-81.hsd1.il.comcast.net [98.220.238.81]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 3F9582187F; Fri, 10 Jan 2020 20:35:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578688540; bh=Bix0dUf7a7fsuKuY6E6H+bdNW+apm7NX4GXgPTHh/wM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:In-Reply-To: References:From; b=y/FzATzJtiwpDxYfyM3djDisjdh2HrznDtj9QQfBVqi+C9mN6ax/0PjVHxrD6YNmJ QFdQUpz44/2iQ7QFMX8KYKOKAGqAmc0zQJyLLltPAQH552iJaYvuvfUA++47LAxKxe jY/tN8CvcWV32KNVPgBvi+dA2+mGl6qA0IzqMzjU= From: Tom Zanussi To: rostedt@goodmis.org Cc: artem.bityutskiy@linux.intel.com, mhiramat@kernel.org, linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org Subject: [PATCH v2 11/12] tracing: Add kprobe event command generation test module Date: Fri, 10 Jan 2020 14:35:17 -0600 Message-Id: X-Mailer: git-send-email 2.14.1 In-Reply-To: References: In-Reply-To: References: Sender: linux-rt-users-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rt-users@vger.kernel.org Add a test module that checks the basic functionality of the in-kernel kprobe event command generation API by creating kprobe events from a module. Signed-off-by: Tom Zanussi --- kernel/trace/Kconfig | 12 ++ kernel/trace/Makefile | 1 + kernel/trace/kprobe_event_gen_test.c | 223 +++++++++++++++++++++++++++++++++++ 3 files changed, 236 insertions(+) create mode 100644 kernel/trace/kprobe_event_gen_test.c diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 0597d60158b4..3e1b34ada52a 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -788,6 +788,18 @@ config SYNTH_EVENT_GEN_TEST If unsure, say N. +config KPROBE_EVENT_GEN_TEST + tristate "Test module for in-kernel kprobe event generation" + depends on KPROBE_EVENTS + help + This option creates a test module to check the base + functionality of in-kernel kprobe event definition. + + To test, insert the module, and then check the trace buffer + for the generated kprobe events. + + If unsure, say N. + config TRACE_EVAL_MAP_FILE bool "Show eval mappings for trace events" depends on TRACING diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile index 99de699c6062..0da59827babd 100644 --- a/kernel/trace/Makefile +++ b/kernel/trace/Makefile @@ -45,6 +45,7 @@ obj-$(CONFIG_TRACING) += trace_printk.o obj-$(CONFIG_TRACING_MAP) += tracing_map.o obj-$(CONFIG_PREEMPTIRQ_DELAY_TEST) += preemptirq_delay_test.o obj-$(CONFIG_SYNTH_EVENT_GEN_TEST) += synth_event_gen_test.o +obj-$(CONFIG_KPROBE_EVENT_GEN_TEST) += kprobe_event_gen_test.o obj-$(CONFIG_CONTEXT_SWITCH_TRACER) += trace_sched_switch.o obj-$(CONFIG_FUNCTION_TRACER) += trace_functions.o obj-$(CONFIG_PREEMPTIRQ_TRACEPOINTS) += trace_preemptirq.o diff --git a/kernel/trace/kprobe_event_gen_test.c b/kernel/trace/kprobe_event_gen_test.c new file mode 100644 index 000000000000..06d99c62b29b --- /dev/null +++ b/kernel/trace/kprobe_event_gen_test.c @@ -0,0 +1,223 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Test module for in-kernel kprobe event creation and generation. + * + * Copyright (C) 2019 Tom Zanussi + */ + +#include +#include +#include "trace.h" + +/* + * This module is a simple test of basic functionality for in-kernel + * kprobe/kretprobe event creation. The first test uses + * gen_kprobe_event(), add_probe_fields() and create_dynevent() to + * create a kprobe event, which is then enabled in order to generate + * trace output. The second creates a kretprobe event using + * gen_kretprobe_event() and create_dynevent, and is also then + * enabled. + * + * To test, select CONFIG_KPROBE_EVENT_GEN_TEST and build the module. + * Then: + * + * # insmod kernel/trace/kprobe_event_gen_test.ko + * # cat /sys/kernel/debug/tracing/trace + * + * You should see many instances of the "gen_kprobe_test" and + * "gen_kretprobe_test" events in the trace buffer. + * + * To remove the events, remove the module: + * + * # rmmod kprobe_event_gen_test + * + */ + +static struct trace_event_file *gen_kprobe_test; +static struct trace_event_file *gen_kretprobe_test; + +/* + * Test to make sure we can create a kprobe event, then add more + * fields. + */ +static int __init test_gen_kprobe_cmd(void) +{ + struct dynevent_cmd cmd; + char *buf; + int ret; + + /* Create a buffer to hold the generated command */ + buf = kzalloc(MAX_DYNEVENT_CMD_LEN, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + /* Before generating the command, initialize the cmd object */ + kprobe_dynevent_cmd_init(&cmd, buf, MAX_DYNEVENT_CMD_LEN); + + /* + * Define the gen_kprobe_test event with the first 2 kprobe + * fields. + */ + ret = gen_kprobe_cmd(&cmd, "gen_kprobe_test", "do_sys_open", + "dfd=%ax", "filename=%dx"); + if (ret) + goto free; + + /* Use add_probe_fields to add the rest of the fields */ + + ret = add_probe_fields(&cmd, "flags=%cx", "mode=+4($stack)"); + if (ret) + goto free; + + /* + * This actually creates the event. + */ + ret = create_dynevent(&cmd); + if (ret) + goto free; + + /* + * Now get the gen_kprobe_test event file. We need to prevent + * the instance and event from disappearing from underneath + * us, which get_event_file() does (though in this case we're + * using the top-level instance which never goes away). + */ + gen_kprobe_test = get_event_file(NULL, "kprobes", + "gen_kprobe_test"); + if (IS_ERR(gen_kprobe_test)) { + ret = PTR_ERR(gen_kprobe_test); + goto delete; + } + + /* Enable the event or you won't see anything */ + ret = trace_array_set_clr_event(gen_kprobe_test->tr, + "kprobes", "gen_kprobe_test", true); + if (ret) { + put_event_file(gen_kprobe_test); + goto delete; + } + out: + return ret; + delete: + /* We got an error after creating the event, delete it */ + ret = delete_kprobe_event("gen_kprobe_test"); + free: + kfree(buf); + + goto out; +} + +/* + * Test to make sure we can create a kretprobe event. + */ +static int __init test_gen_kretprobe_cmd(void) +{ + struct dynevent_cmd cmd; + char *buf; + int ret; + + /* Create a buffer to hold the generated command */ + buf = kzalloc(MAX_DYNEVENT_CMD_LEN, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + /* Before generating the command, initialize the cmd object */ + kprobe_dynevent_cmd_init(&cmd, buf, MAX_DYNEVENT_CMD_LEN); + + /* + * Define the kretprobe event. + */ + ret = gen_kretprobe_cmd(&cmd, "gen_kretprobe_test", "do_sys_open", + "$retval"); + if (ret) + goto free; + + /* + * This actually creates the event. + */ + ret = create_dynevent(&cmd); + if (ret) + goto free; + + /* + * Now get the gen_kretprobe_test event file. We need to prevent + * the instance and event from disappearing from underneath + * us, which get_event_file() does (though in this case we're + * using the top-level instance which never goes away). + */ + gen_kretprobe_test = get_event_file(NULL, "kprobes", + "gen_kretprobe_test"); + if (IS_ERR(gen_kretprobe_test)) { + ret = PTR_ERR(gen_kretprobe_test); + goto delete; + } + + /* Enable the event or you won't see anything */ + ret = trace_array_set_clr_event(gen_kretprobe_test->tr, + "kprobes", "gen_kretprobe_test", true); + if (ret) { + put_event_file(gen_kretprobe_test); + goto delete; + } + out: + return ret; + delete: + /* We got an error after creating the event, delete it */ + ret = delete_kprobe_event("gen_kretprobe_test"); + free: + kfree(buf); + + goto out; +} + +static int __init kprobe_event_gen_test_init(void) +{ + int ret; + + ret = test_gen_kprobe_cmd(); + if (ret) + return ret; + + ret = test_gen_kretprobe_cmd(); + if (ret) { + WARN_ON(trace_array_set_clr_event(gen_kretprobe_test->tr, + "kprobes", + "gen_kretprobe_test", false)); + put_event_file(gen_kretprobe_test); + WARN_ON(delete_kprobe_event("gen_kretprobe_test")); + } + + return ret; +} + +static void __exit kprobe_event_gen_test_exit(void) +{ + /* Disable the event or you can't remove it */ + WARN_ON(trace_array_set_clr_event(gen_kprobe_test->tr, + "kprobes", + "gen_kprobe_test", false)); + + /* Now give the file and instance back */ + put_event_file(gen_kprobe_test); + + /* Now unregister and free the event */ + WARN_ON(delete_kprobe_event("gen_kprobe_test")); + + /* Disable the event or you can't remove it */ + WARN_ON(trace_array_set_clr_event(gen_kprobe_test->tr, + "kprobes", + "gen_kretprobe_test", false)); + + /* Now give the file and instance back */ + put_event_file(gen_kretprobe_test); + + /* Now unregister and free the event */ + WARN_ON(delete_kprobe_event("gen_kretprobe_test")); +} + +module_init(kprobe_event_gen_test_init) +module_exit(kprobe_event_gen_test_exit) + +MODULE_AUTHOR("Tom Zanussi"); +MODULE_DESCRIPTION("kprobe event generation test"); +MODULE_LICENSE("GPL v2"); -- 2.14.1