From: Peter Zijlstra peterz@infradead.org
[ Upstream commit a9cd8194e1e6bd09619954721dfaf0f94fe2003e ]
Event timestamps are serialized using ctx->lock, make sure to hold it over reading all values.
Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Peter Zijlstra peterz@infradead.org Cc: Thomas Gleixner tglx@linutronix.de Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Sasha Levin alexander.levin@verizon.com --- kernel/events/core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/events/core.c b/kernel/events/core.c index 10cdb9c26b5d..4f1d4bfc607a 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -4433,6 +4433,8 @@ static int __perf_read_group_add(struct perf_event *leader, if (ret) return ret;
+ raw_spin_lock_irqsave(&ctx->lock, flags); + /* * Since we co-schedule groups, {enabled,running} times of siblings * will be identical to those of the leader, so we only publish one @@ -4455,8 +4457,6 @@ static int __perf_read_group_add(struct perf_event *leader, if (read_format & PERF_FORMAT_ID) values[n++] = primary_event_id(leader);
- raw_spin_lock_irqsave(&ctx->lock, flags); - list_for_each_entry(sub, &leader->sibling_list, group_entry) { values[n++] += perf_event_count(sub); if (read_format & PERF_FORMAT_ID)