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Commit c7c6b1fe authored by Li Zefan's avatar Li Zefan Committed by Steven Rostedt
Browse files

ftrace: Allow to remove a single function from function graph filter 



I don't see why we can only clear all functions from the filter.

After patching:

  # echo sys_open > set_graph_function
  # echo sys_close >> set_graph_function
  # cat set_graph_function
  sys_open
  sys_close
  # echo '!sys_close' >> set_graph_function
  # cat set_graph_function
  sys_open

Signed-off-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4B726388.2000408@cn.fujitsu.com>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent ede55c9d

kernel/trace/ftrace.c

+31 −20
Original line number Diff line number Diff line
@@ -2426,6 +2426,7 @@ static const struct file_operations ftrace_notrace_fops = { 
static DEFINE_MUTEX(graph_lock);



int ftrace_graph_count;

int ftrace_graph_filter_enabled;

unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;



static void *
@@ -2448,7 +2449,7 @@ static void *g_start(struct seq_file *m, loff_t *pos) 
	mutex_lock(&graph_lock);



	/* Nothing, tell g_show to print all functions are enabled */

	if (!ftrace_graph_count && !*pos)

	if (!ftrace_graph_filter_enabled && !*pos)

		return (void *)1;



	return __g_next(m, pos);
@@ -2494,6 +2495,7 @@ ftrace_graph_open(struct inode *inode, struct file *file) 
	mutex_lock(&graph_lock);

	if ((file->f_mode & FMODE_WRITE) &&

	    (file->f_flags & O_TRUNC)) {

		ftrace_graph_filter_enabled = 0;

		ftrace_graph_count = 0;

		memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));

	}
@@ -2519,7 +2521,7 @@ ftrace_set_func(unsigned long *array, int *idx, char *buffer) 
	struct dyn_ftrace *rec;

	struct ftrace_page *pg;

	int search_len;

	int found = 0;

	int fail = 1;

	int type, not;

	char *search;

	bool exists;
@@ -2530,37 +2532,51 @@ ftrace_set_func(unsigned long *array, int *idx, char *buffer) 


	/* decode regex */

	type = filter_parse_regex(buffer, strlen(buffer), &search, &not);

	if (not)

		return -EINVAL;

	if (!not && *idx >= FTRACE_GRAPH_MAX_FUNCS)

		return -EBUSY;



	search_len = strlen(search);



	mutex_lock(&ftrace_lock);

	do_for_each_ftrace_rec(pg, rec) {



		if (*idx >= FTRACE_GRAPH_MAX_FUNCS)

			break;



		if (rec->flags & (FTRACE_FL_FAILED | FTRACE_FL_FREE))

			continue;



		if (ftrace_match_record(rec, search, search_len, type)) {

			/* ensure it is not already in the array */

			/* if it is in the array */

			exists = false;

			for (i = 0; i < *idx; i++)

			for (i = 0; i < *idx; i++) {

				if (array[i] == rec->ip) {

					exists = true;

					break;

				}

			if (!exists)

			}



			if (!not) {

				fail = 0;

				if (!exists) {

					array[(*idx)++] = rec->ip;

			found = 1;

					if (*idx >= FTRACE_GRAPH_MAX_FUNCS)

						goto out;

				}

			} else {

				if (exists) {

					array[i] = array[--(*idx)];

					array[*idx] = 0;

					fail = 0;

				}

			}

		}

	} while_for_each_ftrace_rec();



out:

	mutex_unlock(&ftrace_lock);



	return found ? 0 : -EINVAL;

	if (fail)

		return -EINVAL;



	ftrace_graph_filter_enabled = 1;

	return 0;

}



static ssize_t
@@ -2570,16 +2586,11 @@ ftrace_graph_write(struct file *file, const char __user *ubuf, 
	struct trace_parser parser;

	ssize_t read, ret;



	if (!cnt || cnt < 0)

	if (!cnt)

		return 0;



	mutex_lock(&graph_lock);



	if (ftrace_graph_count >= FTRACE_GRAPH_MAX_FUNCS) {

		ret = -EBUSY;

		goto out_unlock;

	}



	if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX)) {

		ret = -ENOMEM;

		goto out_unlock;

kernel/trace/trace.h

+2 −1
Original line number Diff line number Diff line
@@ -497,6 +497,7 @@ trace_print_graph_duration(unsigned long long duration, struct trace_seq *s); 
#ifdef CONFIG_DYNAMIC_FTRACE

/* TODO: make this variable */

#define FTRACE_GRAPH_MAX_FUNCS		32

extern int ftrace_graph_filter_enabled;

extern int ftrace_graph_count;

extern unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS];
@@ -504,7 +505,7 @@ static inline int ftrace_graph_addr(unsigned long addr) 
{

	int i;



	if (!ftrace_graph_count)

	if (!ftrace_graph_filter_enabled)

		return 1;



	for (i = 0; i < ftrace_graph_count; i++) {