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Subject[PATCH] perf, sched: Do not delete session object prematurely
Date
The session object is released prematurely when processing
events for latency command. The session's thread objects are
used within the output_lat_thread function.

Runnning following commands:

# perf sched record
# perf sched latency

the latter displays incorrect data and might cause access
violation.

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
---
tools/perf/builtin-sched.c | 22 +++++++++++++++-------
1 files changed, 15 insertions(+), 7 deletions(-)
diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index dcfe887..3d5702c 100644
--- a/tools/perf/builtin-sched.c
+++ b/tools/perf/builtin-sched.c
@@ -1637,23 +1637,29 @@ static struct perf_event_ops event_ops = {
.ordered_samples = true,
};

-static int read_events(void)
+static void read_events(bool destroy, struct perf_session **psession)
{
int err = -EINVAL;
struct perf_session *session = perf_session__new(input_name, O_RDONLY,
0, false, &event_ops);
if (session == NULL)
- return -ENOMEM;
+ die("No Memory");

if (perf_session__has_traces(session, "record -R")) {
err = perf_session__process_events(session, &event_ops);
+ if (err)
+ die("Failed to process events, error %d", err);
+
nr_events = session->hists.stats.nr_events[0];
nr_lost_events = session->hists.stats.total_lost;
nr_lost_chunks = session->hists.stats.nr_events[PERF_RECORD_LOST];
}

- perf_session__delete(session);
- return err;
+ if (destroy)
+ perf_session__delete(session);
+
+ if (psession)
+ *psession = session;
}

static void print_bad_events(void)
@@ -1689,9 +1695,10 @@ static void print_bad_events(void)
static void __cmd_lat(void)
{
struct rb_node *next;
+ struct perf_session *session;

setup_pager();
- read_events();
+ read_events(false, &session);
sort_lat();

printf("\n ---------------------------------------------------------------------------------------------------------------\n");
@@ -1717,6 +1724,7 @@ static void __cmd_lat(void)
print_bad_events();
printf("\n");

+ perf_session__delete(session);
}

static struct trace_sched_handler map_ops = {
@@ -1731,7 +1739,7 @@ static void __cmd_map(void)
max_cpu = sysconf(_SC_NPROCESSORS_CONF);

setup_pager();
- read_events();
+ read_events(true, NULL);
print_bad_events();
}

@@ -1744,7 +1752,7 @@ static void __cmd_replay(void)

test_calibrations();

- read_events();
+ read_events(true, NULL);

printf("nr_run_events: %ld\n", nr_run_events);
printf("nr_sleep_events: %ld\n", nr_sleep_events);
--
1.7.1


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