4.18-stable review patch. If anyone has any objections, please let me know.
------------------ From: Reinette Chatre <[email protected]> commit befb1b3c2703897c5b8ffb0044dc5d0e5f27c5d7 upstream. 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. Suggested-by: Peter Zijlstra <[email protected]> Signed-off-by: Reinette Chatre <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Acked-by: Peter Zijlstra (Intel) <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Link: https://lkml.kernel.org/r/6486385d1f30336e9973b24c8c65f5079543d3d3.1537377064.git.reinette.cha...@intel.com Signed-off-by: Greg Kroah-Hartman <[email protected]> --- kernel/events/core.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -3940,6 +3940,12 @@ int perf_event_read_local(struct perf_ev 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
