mirror of https://gitee.com/openkylin/linux.git
226 lines
5.6 KiB
C
226 lines
5.6 KiB
C
|
// 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");
|