It is possible that a failure can occur during the scheduling of a pinned event. The initial portion of perf_event_read_local() contains the various error checks an event should pass before it can be considered valid. Ensure that the potential scheduling failure of a pinned event is checked for and have a credible error.
Link: http://lkml.kernel.org/r/20180807093615.gy2...@hirez.programming.kicks-ass.net Suggested-by: Peter Zijlstra <pet...@infradead.org> Signed-off-by: Reinette Chatre <reinette.cha...@intel.com> --- kernel/events/core.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/kernel/events/core.c b/kernel/events/core.c index 80cca2b30c4f..005d0f2519fd 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -3940,6 +3940,12 @@ int perf_event_read_local(struct perf_event *event, u64 *value, goto out; } + /* If this is a pinned event it must be running on this CPU */ + if (event->attr.pinned && event->oncpu != smp_processor_id()) { + ret = -EBUSY; + goto out; + } + /* * If the event is currently on this CPU, its either a per-task event, * or local to this CPU. Furthermore it means its ACTIVE (otherwise -- 2.17.0
