The call to smp_call_function_single in perf_event_read() may fail if an invalid or not online CPU index is passed. Warn user if such bug is present and return error.
Signed-off-by: David Carrillo-Cisneros <[email protected]> --- kernel/events/core.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index 803481c..35afbfa 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -3524,9 +3524,11 @@ 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); + /* 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; -- 2.8.0.rc3.226.g39d4020
