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Date: Wed, 13 Aug 2014 00:50:55 +0000
From: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
To: Arnaldo Carvalho de Melo <acme@...nel.org>
Cc: Naohiro Aota <naota@...sp.net>, Ingo Molnar <mingo@...hat.com>,
Paul Mackerras <paulus@...ba.org>,
Peter Zijlstra <a.p.zijlstra@...llo.nl>,
LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH 1/2] [BUGFIX] 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@.../traceevent/event-parse.c in /home/fedora/ksrc/linux-3/tools/perf/perf)
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
Reported-by: Naohiro Aota <naota@...sp.net>
Cc: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc: Paul Mackerras <paulus@...ba.org>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Arnaldo Carvalho de Melo <acme@...nel.org>
---
tools/perf/util/probe-event.c | 84 ++++++++++++++++++++++++++---------------
1 file changed, 54 insertions(+), 30 deletions(-)
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 9a0a183..b4f6555 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -1780,10 +1780,10 @@ 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)
{
- if (errno == ENOENT) {
+ if (err == -ENOENT) {
const char *config;
if (!is_kprobe)
@@ -1791,25 +1791,25 @@ 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(-err));
}
-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 +1820,19 @@ 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 +1940,44 @@ 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
+ pr_warning("Failed to open kprobe events: %s.\n" \
+ "Failed to open uprobe events: %s.\n",
+ strerror(-kp_fd), strerror(-up_fd));
+ 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 +2092,11 @@ 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 +2469,17 @@ 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)
--
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