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Commit 5e45187c authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Arnaldo Carvalho de Melo
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perf probe: Fix --list option to show events only with uprobe events 



Current perf probe --list doesn't work if only CONFIG_UPROBE_EVENTS=y
because it aborts when it fails to open kprobe_events file before
checking uprobe_events file.

This fixes --list option to show dynamic events if it can open either
kprobe_events or uprobe_events. Only if it failed to open both of them,
it shows an error message and aborts.

Without this patch, if we run perf probe -l on the kernel configured
with CONFIG_KPROBE_EVENTS=n and CONFIG_UPROBE_EVENTS=y,

  # perf probe -l
  /sys/kernel/debug/tracing/kprobe_events file does not exist - please rebuild ker
    Error: Failed to show event list.

With this patch,

  # perf probe -l
    probe_perf:alloc_event (on alloc_event@lib/traceevent/event-parse.c in /home/fedora/ksrc/linux-3/tools/perf/perf)

Changes in v2:
 - Use strerror_r instead of strerror.

Reported-by: default avatarNaohiro Aota <naota@elisp.net>
Signed-off-by: default avatarMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Naohiro Aota <naota@elisp.net>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20140813161248.26440.84370.stgit@kbuild-fedora.novalocal


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent d5b4130a

tools/perf/util/probe-event.c

+59 −30
Original line number Diff line number Diff line
@@ -1780,10 +1780,11 @@ static void clear_probe_trace_event(struct probe_trace_event *tev) 
	memset(tev, 0, sizeof(*tev));

}



static void print_warn_msg(const char *file, bool is_kprobe)

static void print_open_warning(int err, bool is_kprobe)

{

	char sbuf[128];



	if (errno == ENOENT) {

	if (err == -ENOENT) {

		const char *config;



		if (!is_kprobe)
@@ -1791,25 +1792,26 @@ static void print_warn_msg(const char *file, bool is_kprobe) 
		else

			config = "CONFIG_KPROBE_EVENTS";



		pr_warning("%s file does not exist - please rebuild kernel"

				" with %s.\n", file, config);

	} else

		pr_warning("Failed to open %s file: %s\n", file,

				strerror(errno));

		pr_warning("%cprobe_events file does not exist"

			   " - please rebuild kernel with %s.\n",

			   is_kprobe ? 'k' : 'u', config);

	} else if (err == -ENOTSUP)

		pr_warning("Debugfs is not mounted.\n");

	else

		pr_warning("Failed to open %cprobe_events: %s\n",

			   is_kprobe ? 'k' : 'u',

			   strerror_r(-err, sbuf, sizeof(sbuf)));

}



static int open_probe_events(const char *trace_file, bool readwrite,

				bool is_kprobe)

static int open_probe_events(const char *trace_file, bool readwrite)

{

	char buf[PATH_MAX];

	const char *__debugfs;

	int ret;



	__debugfs = debugfs_find_mountpoint();

	if (__debugfs == NULL) {

		pr_warning("Debugfs is not mounted.\n");

		return -ENOENT;

	}

	if (__debugfs == NULL)

		return -ENOTSUP;



	ret = e_snprintf(buf, PATH_MAX, "%s/%s", __debugfs, trace_file);

	if (ret >= 0) {
@@ -1820,19 +1822,19 @@ static int open_probe_events(const char *trace_file, bool readwrite, 
			ret = open(buf, O_RDONLY, 0);



		if (ret < 0)

			print_warn_msg(buf, is_kprobe);

			ret = -errno;

	}

	return ret;

}



static int open_kprobe_events(bool readwrite)

{

	return open_probe_events("tracing/kprobe_events", readwrite, true);

	return open_probe_events("tracing/kprobe_events", readwrite);

}



static int open_uprobe_events(bool readwrite)

{

	return open_probe_events("tracing/uprobe_events", readwrite, false);

	return open_probe_events("tracing/uprobe_events", readwrite);

}



/* Get raw string list of current kprobe_events  or uprobe_events */
@@ -1940,27 +1942,47 @@ static int __show_perf_probe_events(int fd, bool is_kprobe) 
/* List up current perf-probe events */

int show_perf_probe_events(void)

{

	int fd, ret;

	int kp_fd, up_fd, ret;



	setup_pager();

	fd = open_kprobe_events(false);



	if (fd < 0)

		return fd;



	ret = init_symbol_maps(false);

	if (ret < 0)

		return ret;



	ret = __show_perf_probe_events(fd, true);

	close(fd);

	kp_fd = open_kprobe_events(false);

	if (kp_fd >= 0) {

		ret = __show_perf_probe_events(kp_fd, true);

		close(kp_fd);

		if (ret < 0)

			goto out;

	}



	fd = open_uprobe_events(false);

	if (fd >= 0) {

		ret = __show_perf_probe_events(fd, false);

		close(fd);

	up_fd = open_uprobe_events(false);

	if (kp_fd < 0 && up_fd < 0) {

		/* Both kprobes and uprobes are disabled, warn it. */

		if (kp_fd == -ENOTSUP && up_fd == -ENOTSUP)

			pr_warning("Debugfs is not mounted.\n");

		else if (kp_fd == -ENOENT && up_fd == -ENOENT)

			pr_warning("Please rebuild kernel with "

				   "CONFIG_KPROBE_EVENTS or/and "

				   "CONFIG_UPROBE_EVENTS.\n");

		else {

			char sbuf[128];

			pr_warning("Failed to open kprobe events: %s.\n",

				   strerror_r(-kp_fd, sbuf, sizeof(sbuf)));

			pr_warning("Failed to open uprobe events: %s.\n",

				   strerror_r(-up_fd, sbuf, sizeof(sbuf)));

		}

		ret = kp_fd;

		goto out;

	}



	if (up_fd >= 0) {

		ret = __show_perf_probe_events(up_fd, false);

		close(up_fd);

	}

out:

	exit_symbol_maps();

	return ret;

}
@@ -2075,8 +2097,11 @@ static int __add_probe_trace_events(struct perf_probe_event *pev, 
	else

		fd = open_kprobe_events(true);



	if (fd < 0)

	if (fd < 0) {

		print_open_warning(fd, !pev->uprobes);

		return fd;

	}



	/* Get current event names */

	namelist = get_probe_trace_event_names(fd, false);

	if (!namelist) {
@@ -2449,13 +2474,17 @@ int del_perf_probe_events(struct strlist *dellist) 


	/* Get current event names */

	kfd = open_kprobe_events(true);

	if (kfd < 0)

	if (kfd < 0) {

		print_open_warning(kfd, true);

		return kfd;

	}



	namelist = get_probe_trace_event_names(kfd, true);

	ufd = open_uprobe_events(true);



	if (ufd >= 0)

	if (ufd < 0)

		print_open_warning(ufd, false);

	else

		unamelist = get_probe_trace_event_names(ufd, true);



	if (namelist == NULL && unamelist == NULL)