diff options
| -rw-r--r-- | kernel/trace/Kconfig | 12 | ||||
| -rw-r--r-- | kernel/trace/Makefile | 1 | ||||
| -rw-r--r-- | kernel/trace/kprobe_event_gen_test.c | 225 |
3 files changed, 238 insertions, 0 deletions
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 4f2041166a2f..4484e783f68d 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -787,6 +787,18 @@ 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 32012f50fb79..f9dcd19165fa 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..18b0f1cbb947 --- /dev/null +++ b/kernel/trace/kprobe_event_gen_test.c @@ -0,0 +1,225 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Test module for in-kernel kprobe event creation and generation. + * + * Copyright (C) 2019 Tom Zanussi <zanussi@kernel.org> + */ + +#include <linux/module.h> +#include <linux/trace_events.h> + +/* + * This module is a simple test of basic functionality for in-kernel + * kprobe/kretprobe event creation. The first test uses + * kprobe_event_gen_cmd_start(), kprobe_event_add_fields() and + * kprobe_event_gen_cmd_end() to create a kprobe event, which is then + * enabled in order to generate trace output. The second creates a + * kretprobe event using kretprobe_event_gen_cmd_start() and + * kretprobe_event_gen_cmd_end(), 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_event_cmd_init(&cmd, buf, MAX_DYNEVENT_CMD_LEN); + + /* + * Define the gen_kprobe_test event with the first 2 kprobe + * fields. + */ + ret = kprobe_event_gen_cmd_start(&cmd, "gen_kprobe_test", + "do_sys_open", + "dfd=%ax", "filename=%dx"); + if (ret) + goto free; + + /* Use kprobe_event_add_fields to add the rest of the fields */ + + ret = kprobe_event_add_fields(&cmd, "flags=%cx", "mode=+4($stack)"); + if (ret) + goto free; + + /* + * This actually creates the event. + */ + ret = kprobe_event_gen_cmd_end(&cmd); + if (ret) + goto free; + + /* + * Now get the gen_kprobe_test event file. We need to prevent + * the instance and event from disappearing from underneath + * us, which trace_get_event_file() does (though in this case + * we're using the top-level instance which never goes away). + */ + gen_kprobe_test = trace_get_event_file(NULL, "kprobes", + "gen_kprobe_test"); + if (IS_ERR(gen_kprobe_test)) { + ret = PTR_ERR(gen_kprobe_test); + goto delete; + } + + /* Enable the event or you won't see anything */ + ret = trace_array_set_clr_event(gen_kprobe_test->tr, + "kprobes", "gen_kprobe_test", true); + if (ret) { + trace_put_event_file(gen_kprobe_test); + goto delete; + } + out: + return ret; + delete: + /* We got an error after creating the event, delete it */ + ret = kprobe_event_delete("gen_kprobe_test"); + free: + kfree(buf); + + goto out; +} + +/* + * Test to make sure we can create a kretprobe event. + */ +static int __init test_gen_kretprobe_cmd(void) +{ + struct dynevent_cmd cmd; + char *buf; + int ret; + + /* Create a buffer to hold the generated command */ + buf = kzalloc(MAX_DYNEVENT_CMD_LEN, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + /* Before generating the command, initialize the cmd object */ + kprobe_event_cmd_init(&cmd, buf, MAX_DYNEVENT_CMD_LEN); + + /* + * Define the kretprobe event. + */ + ret = kretprobe_event_gen_cmd_start(&cmd, "gen_kretprobe_test", + "do_sys_open", + "$retval"); + if (ret) + goto free; + + /* + * This actually creates the event. + */ + ret = kretprobe_event_gen_cmd_end(&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 trace_get_event_file() does (though in + * this case we're using the top-level instance which never + * goes away). + */ + gen_kretprobe_test = trace_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) { + trace_put_event_file(gen_kretprobe_test); + goto delete; + } + out: + return ret; + delete: + /* We got an error after creating the event, delete it */ + ret = kprobe_event_delete("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)); + trace_put_event_file(gen_kretprobe_test); + WARN_ON(kprobe_event_delete("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 */ + trace_put_event_file(gen_kprobe_test); + + /* Now unregister and free the event */ + WARN_ON(kprobe_event_delete("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 */ + trace_put_event_file(gen_kretprobe_test); + + /* Now unregister and free the event */ + WARN_ON(kprobe_event_delete("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"); |