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Commit 8f31bfe5 authored by Li Zefan's avatar Li Zefan Committed by Ingo Molnar
Browse files

tracing/events: clean up for ftrace_set_clr_event() 



Add a helper function __ftrace_set_clr_event(), and replace some
ftrace_set_clr_event() calls with this helper, thus we don't need any
kstrdup() or kmalloc().

As a side effect, this patch fixes an issue in self tests code, which is
similar to the one fixed in commit d6bf81ef
("tracing: append ":*" to internal setting of system events")

It's a small issue and won't cause any bug in fact, but we should do things
right anyway.

[ Impact: prevent spurious event-enabling in tracing self-tests ]

Signed-off-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
Acked-by: default avatarSteven Rostedt <rostedt@goodmis.org>
Acked-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4A03998E.3020503@cn.fujitsu.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 74f4fd21

kernel/trace/trace_events.c

+46 −80
Original line number Diff line number Diff line
@@ -111,11 +111,44 @@ static void ftrace_event_enable_disable(struct ftrace_event_call *call, 
	}

}



static int ftrace_set_clr_event(char *buf, int set)

/*

 * __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events.

 */

static int __ftrace_set_clr_event(const char *match, const char *sub,

				  const char *event, int set)

{

	struct ftrace_event_call *call;

	int ret;



	mutex_lock(&event_mutex);

	list_for_each_entry(call, &ftrace_events, list) {



		if (!call->name || !call->regfunc)

			continue;



		if (match &&

		    strcmp(match, call->name) != 0 &&

		    strcmp(match, call->system) != 0)

			continue;



		if (sub && strcmp(sub, call->system) != 0)

			continue;



		if (event && strcmp(event, call->name) != 0)

			continue;



		ftrace_event_enable_disable(call, set);



		ret = 0;

	}

	mutex_unlock(&event_mutex);



	return ret;

}



static int ftrace_set_clr_event(char *buf, int set)

{

	char *event = NULL, *sub = NULL, *match;

	int ret = -EINVAL;



	/*

	 * The buf format can be <subsystem>:<event-name>
@@ -141,30 +174,7 @@ static int ftrace_set_clr_event(char *buf, int set) 
			event = NULL;

	}



	mutex_lock(&event_mutex);

	list_for_each_entry(call, &ftrace_events, list) {



		if (!call->name || !call->regfunc)

			continue;



		if (match &&

		    strcmp(match, call->name) != 0 &&

		    strcmp(match, call->system) != 0)

			continue;



		if (sub && strcmp(sub, call->system) != 0)

			continue;



		if (event && strcmp(event, call->name) != 0)

			continue;



		ftrace_event_enable_disable(call, set);



		ret = 0;

	}

	mutex_unlock(&event_mutex);



	return ret;

	return __ftrace_set_clr_event(match, sub, event, set);

}



/* 128 should be much more than enough */
@@ -408,18 +418,14 @@ system_enable_read(struct file *filp, char __user *ubuf, size_t cnt, 
	struct ftrace_event_call *call;

	char buf[2];

	int set = -1;

	int all = 0;

	int ret;



	if (system[0] == '*')

		all = 1;



	mutex_lock(&event_mutex);

	list_for_each_entry(call, &ftrace_events, list) {

		if (!call->name || !call->regfunc)

			continue;



		if (!all && strcmp(call->system, system) != 0)

		if (system && strcmp(call->system, system) != 0)

			continue;



		/*
@@ -480,7 +486,6 @@ system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt, 
{

	const char *system = filp->private_data;

	unsigned long val;

	char *command;

	char buf[64];

	ssize_t ret;
@@ -500,30 +505,16 @@ system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt, 
	if (ret < 0)

		return ret;



	switch (val) {

	case 0:

	case 1:

		break;



	default:

	if (val != 0 && val != 1)

		return -EINVAL;

	}



	/* +3 for the ":*\0" */

	command = kmalloc(strlen(system)+3, GFP_KERNEL);

	if (!command)

		return -ENOMEM;

	sprintf(command, "%s:*", system);



	ret = ftrace_set_clr_event(command, val);

	ret = __ftrace_set_clr_event(NULL, system, NULL, val);

	if (ret)

		goto out_free;

		goto out;



	ret = cnt;



 out_free:

	kfree(command);



out:

	*ppos += cnt;



	return ret;
@@ -1181,7 +1172,7 @@ static __init int event_trace_init(void) 
			  &ftrace_show_header_fops);



	trace_create_file("enable", 0644, d_events,

			  "*", &ftrace_system_enable_fops);

			  NULL, &ftrace_system_enable_fops);



	for_each_event(call, __start_ftrace_events, __stop_ftrace_events) {

		/* The linker may leave blanks */
@@ -1259,7 +1250,6 @@ static __init void event_trace_self_tests(void) 
{

	struct ftrace_event_call *call;

	struct event_subsystem *system;

	char *sysname;

	int ret;



	pr_info("Running tests on trace events:\n");
@@ -1305,14 +1295,7 @@ static __init void event_trace_self_tests(void) 


		pr_info("Testing event system %s: ", system->name);



		/* ftrace_set_clr_event can modify the name passed in. */

		sysname = kstrdup(system->name, GFP_KERNEL);

		if (WARN_ON(!sysname)) {

			pr_warning("Can't allocate memory, giving up!\n");

			return;

		}

		ret = ftrace_set_clr_event(sysname, 1);

		kfree(sysname);

		ret = __ftrace_set_clr_event(NULL, system->name, NULL, 1);

		if (WARN_ON_ONCE(ret)) {

			pr_warning("error enabling system %s\n",

				   system->name);
@@ -1321,14 +1304,7 @@ static __init void event_trace_self_tests(void) 


		event_test_stuff();



		sysname = kstrdup(system->name, GFP_KERNEL);

		if (WARN_ON(!sysname)) {

			pr_warning("Can't allocate memory, giving up!\n");

			return;

		}

		ret = ftrace_set_clr_event(sysname, 0);

		kfree(sysname);



		ret = __ftrace_set_clr_event(NULL, system->name, NULL, 0);

		if (WARN_ON_ONCE(ret))

			pr_warning("error disabling system %s\n",

				   system->name);
@@ -1341,15 +1317,8 @@ static __init void event_trace_self_tests(void) 
	pr_info("Running tests on all trace events:\n");

	pr_info("Testing all events: ");



	sysname = kmalloc(4, GFP_KERNEL);

	if (WARN_ON(!sysname)) {

		pr_warning("Can't allocate memory, giving up!\n");

		return;

	}

	memcpy(sysname, "*:*", 4);

	ret = ftrace_set_clr_event(sysname, 1);

	ret = __ftrace_set_clr_event(NULL, NULL, NULL, 1);

	if (WARN_ON_ONCE(ret)) {

		kfree(sysname);

		pr_warning("error enabling all events\n");

		return;

	}
@@ -1357,10 +1326,7 @@ static __init void event_trace_self_tests(void) 
	event_test_stuff();



	/* reset sysname */

	memcpy(sysname, "*:*", 4);

	ret = ftrace_set_clr_event(sysname, 0);

	kfree(sysname);



	ret = __ftrace_set_clr_event(NULL, NULL, NULL, 0);

	if (WARN_ON_ONCE(ret)) {

		pr_warning("error disabling all events\n");

		return;