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Commit 7cf0b79e authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Arnaldo Carvalho de Melo
Browse files

perf probe: Fix error message if get_real_path() failed 



Perf probe -L shows incorrect error message (Dwarf error) if it fails to find
source file. This can confuse users.

# ./perf probe -s /nowhere -L vfs_read
Debuginfo analysis failed. (-2)
  Error: Failed to show lines. (-2)

With this patch, it shows correct message.

# ./perf probe -s /nowhere -L vfs_read
Failed to find source file. (-2)
  Error: Failed to show lines. (-2)

LKML-Reference: <4C36EBDB.4020308@hitachi.com>
Cc: Chase Douglas <chase.douglas@canonical.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Acked-by: default avatarChase Douglas <chase.douglas@canonical.com>
Signed-off-by: default avatarMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 0dd9ac63

tools/perf/util/probe-event.c

+59 −0
Original line number Diff line number Diff line
@@ -195,6 +195,55 @@ static int try_to_find_kprobe_trace_events(struct perf_probe_event *pev, 
	return ntevs;

}



/*

 * Find a src file from a DWARF tag path. Prepend optional source path prefix

 * and chop off leading directories that do not exist. Result is passed back as

 * a newly allocated path on success.

 * Return 0 if file was found and readable, -errno otherwise.

 */

static int get_real_path(const char *raw_path, char **new_path)

{

	if (!symbol_conf.source_prefix) {

		if (access(raw_path, R_OK) == 0) {

			*new_path = strdup(raw_path);

			return 0;

		} else

			return -errno;

	}



	*new_path = malloc((strlen(symbol_conf.source_prefix) +

			    strlen(raw_path) + 2));

	if (!*new_path)

		return -ENOMEM;



	for (;;) {

		sprintf(*new_path, "%s/%s", symbol_conf.source_prefix,

			raw_path);



		if (access(*new_path, R_OK) == 0)

			return 0;



		switch (errno) {

		case ENAMETOOLONG:

		case ENOENT:

		case EROFS:

		case EFAULT:

			raw_path = strchr(++raw_path, '/');

			if (!raw_path) {

				free(*new_path);

				*new_path = NULL;

				return -ENOENT;

			}

			continue;



		default:

			free(*new_path);

			*new_path = NULL;

			return -errno;

		}

	}

}



#define LINEBUF_SIZE 256

#define NR_ADDITIONAL_LINES 2
@@ -244,6 +293,7 @@ int show_line_range(struct line_range *lr) 
	struct line_node *ln;

	FILE *fp;

	int fd, ret;

	char *tmp;



	/* Search a line range */

	ret = init_vmlinux();
@@ -266,6 +316,15 @@ int show_line_range(struct line_range *lr) 
		return ret;

	}



	/* Convert source file path */

	tmp = lr->path;

	ret = get_real_path(tmp, &lr->path);

	free(tmp);	/* Free old path */

	if (ret < 0) {

		pr_warning("Failed to find source file. (%d)\n", ret);

		return ret;

	}



	setup_pager();



	if (lr->function)

tools/perf/util/probe-finder.c

+5 −56
Original line number Diff line number Diff line
@@ -58,55 +58,6 @@ static int strtailcmp(const char *s1, const char *s2) 
	return 0;

}



/*

 * Find a src file from a DWARF tag path. Prepend optional source path prefix

 * and chop off leading directories that do not exist. Result is passed back as

 * a newly allocated path on success.

 * Return 0 if file was found and readable, -errno otherwise.

 */

static int get_real_path(const char *raw_path, char **new_path)

{

	if (!symbol_conf.source_prefix) {

		if (access(raw_path, R_OK) == 0) {

			*new_path = strdup(raw_path);

			return 0;

		} else

			return -errno;

	}



	*new_path = malloc((strlen(symbol_conf.source_prefix) +

			    strlen(raw_path) + 2));

	if (!*new_path)

		return -ENOMEM;



	for (;;) {

		sprintf(*new_path, "%s/%s", symbol_conf.source_prefix,

			raw_path);



		if (access(*new_path, R_OK) == 0)

			return 0;



		switch (errno) {

		case ENAMETOOLONG:

		case ENOENT:

		case EROFS:

		case EFAULT:

			raw_path = strchr(++raw_path, '/');

			if (!raw_path) {

				free(*new_path);

				*new_path = NULL;

				return -ENOENT;

			}

			continue;



		default:

			free(*new_path);

			*new_path = NULL;

			return -errno;

		}

	}

}



/* Line number list operations */



/* Add a line to line number list */
@@ -1256,13 +1207,11 @@ int find_perf_probe_point(int fd, unsigned long addr, 
static int line_range_add_line(const char *src, unsigned int lineno,

			       struct line_range *lr)

{

	int ret;



	/* Copy real path */

	/* Copy source path */

	if (!lr->path) {

		ret = get_real_path(src, &lr->path);

		if (ret != 0)

			return ret;

		lr->path = strdup(src);

		if (lr->path == NULL)

			return -ENOMEM;

	}

	return line_list__add_line(&lr->line_list, lineno);

}
@@ -1460,7 +1409,7 @@ int find_line_range(int fd, struct line_range *lr) 
		}

		off = noff;

	}

	pr_debug("path: %lx\n", (unsigned long)lr->path);

	pr_debug("path: %s\n", lr->path);

	dwarf_end(dbg);



	return (ret < 0) ? ret : lf.found;