[PATCH 02/47] perf: Do not get values from disabled counters in group format read

From: Arnaldo Carvalho de Melo
Date: Wed Aug 07 2013 - 17:19:16 EST

From: Jiri Olsa <jolsa@xxxxxxxxxx>

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@xxxxxxxxxx>
Acked-by: Namhyung Kim <namhyung@xxxxxxxxxx>
Acked-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Corey Ashford <cjashfor@xxxxxxxxxxxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Link: http://lkml.kernel.org/n/tip-wwkjb0bbcuslnz0klrmqi26r@xxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
kernel/events/core.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 5200b60..e82e700 100644
--- 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))

values[n++] = perf_event_count(sub);

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