perf tools: Fix probing the kernel API with cpu-wide events
Fall back to probing with the current pid if cpu-wide probing fails.
This primarily affects the setting of comm_exec flag when the user is
un-privileged and /proc/sys/kernel/perf_event_paranoid > 0.
The change to comm_exec can be observed by using -vv with perf record
and a kernel that supports comm_exec.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1407855871-15024-4-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/record.c b/tools/perf/util/record.c
index 58267a8..e778afd 100644
--- a/tools/perf/util/record.c
+++ b/tools/perf/util/record.c
@@ -14,6 +14,7 @@
struct perf_evsel *evsel;
unsigned long flags = perf_event_open_cloexec_flag();
int err = -EAGAIN, fd;
+ static pid_t pid = -1;
evlist = perf_evlist__new();
if (!evlist)
@@ -24,14 +25,22 @@
evsel = perf_evlist__first(evlist);
- fd = sys_perf_event_open(&evsel->attr, -1, cpu, -1, flags);
- if (fd < 0)
- goto out_delete;
+ while (1) {
+ fd = sys_perf_event_open(&evsel->attr, pid, cpu, -1, flags);
+ if (fd < 0) {
+ if (pid == -1 && errno == EACCES) {
+ pid = 0;
+ continue;
+ }
+ goto out_delete;
+ }
+ break;
+ }
close(fd);
fn(evsel);
- fd = sys_perf_event_open(&evsel->attr, -1, cpu, -1, flags);
+ fd = sys_perf_event_open(&evsel->attr, pid, cpu, -1, flags);
if (fd < 0) {
if (errno == EINVAL)
err = -EINVAL;
@@ -201,6 +210,7 @@
struct perf_evsel *evsel;
int err, fd, cpu;
bool ret = false;
+ pid_t pid = -1;
temp_evlist = perf_evlist__new();
if (!temp_evlist)
@@ -221,12 +231,20 @@
cpu = evlist->cpus->map[0];
}
- fd = sys_perf_event_open(&evsel->attr, -1, cpu, -1,
- perf_event_open_cloexec_flag());
- if (fd >= 0) {
- close(fd);
- ret = true;
+ while (1) {
+ fd = sys_perf_event_open(&evsel->attr, pid, cpu, -1,
+ perf_event_open_cloexec_flag());
+ if (fd < 0) {
+ if (pid == -1 && errno == EACCES) {
+ pid = 0;
+ continue;
+ }
+ goto out_delete;
+ }
+ break;
}
+ close(fd);
+ ret = true;
out_delete:
perf_evlist__delete(temp_evlist);
