diff options
| -rw-r--r-- | kernel/events/core.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c index a5fc5c8cdfb0..5650f5317e0c 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -3549,9 +3549,10 @@ static int perf_event_read(struct perf_event *event, bool group) .group = group, .ret = 0, }; - smp_call_function_single(event->oncpu, - __perf_event_read, &data, 1); - ret = data.ret; + ret = smp_call_function_single(event->oncpu, __perf_event_read, &data, 1); + /* The event must have been read from an online CPU: */ + WARN_ON_ONCE(ret); + ret = ret ? : data.ret; } else if (event->state == PERF_EVENT_STATE_INACTIVE) { struct perf_event_context *ctx = event->ctx; unsigned long flags; |