perf: Do not get values from disabled counters in group format read

It's possible some of the counters in the group could be
disabled when sampling member of the event group is reading
the rest via PERF_SAMPLE_READ sample type processing. Disabled
counters could then produce wrong numbers.

Fixing that by reading only enabled counters for PERF_SAMPLE_READ
sample type processing.

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-wwkjb0bbcuslnz0klrmqi26r@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 5200b608b4818a7a80887a5127dc276b96200ce0..e82e70025d4233ea67cbb9b3ae280f759896ba09 100644 (file)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -4388,7 +4388,8 @@ static void perf_output_read_group(struct perf_output_handle *handle,
        list_for_each_entry(sub, &leader->sibling_list, group_entry) {
                n = 0;
 
-               if (sub != event)
+               if ((sub != event) &&
+                   (sub->state == PERF_EVENT_STATE_ACTIVE))
                        sub->pmu->read(sub);
 
                values[n++] = perf_event_count(sub);