[PATCH 1/2] perf: Reset detached siblings' group_flags

[Namhyung Kim <namhyung@kernel.org>]

From: Namhyung Kim <namhyung.kim@lge.com>

Currently if a group_leader event is deleted, the sibling events are
upgraded to singleton events of a same group list.  At this time, the
siblings inherit the leader's group_flags.

However, if the group has mixed hw/sw events the leader's group_flag
does not contain PERF_GROUP_SOFTWARE so sibling sw events will miss
the flag also.  Fix it.

Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 kernel/events/core.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 5c75791d7269..007dfe846d4d 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -1107,8 +1107,9 @@ static void perf_group_detach(struct perf_event *event)
 			list_move_tail(&sibling->group_entry, list);
 		sibling->group_leader = sibling;
 
-		/* Inherit group flags from the previous leader */
-		sibling->group_flags = event->group_flags;
+		/* Reset group flags for each siblings */
+		sibling->group_flags = is_software_event(sibling) ?
+						PERF_GROUP_SOFTWARE : 0;
 	}
 
 out:
-- 
1.7.11.7