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perf probe: Fix --list option to show events only with uprobe events

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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: Naohiro Aota <naota@elisp.net>
Signed-off-by: Masami 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: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Masami Hiramatsu 2014-08-13 16:12:48 +00:00 committed by Arnaldo Carvalho de Melo
parent d5b4130ae6
commit 5e45187cc9
1 changed files with 60 additions and 31 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

91
tools/perf/util/probe-event.c
View file

@ -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);
fd = open_uprobe_events(false);
if (fd >= 0) {
ret = __show_perf_probe_events(fd, false);
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;
}
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)