From ab18409cf05f8e3d20ae3e5347f431947ecc397c Mon Sep 17 00:00:00 2001 From: Reinette Chatre Date: Wed, 19 Sep 2018 10:29:06 -0700 Subject: [PATCH] perf/core: Add sanity check to deal with pinned event failure 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 Signed-off-by: Reinette Chatre Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra (Intel) Cc: fenghua.yu@intel.com Cc: tony.luck@intel.com Cc: acme@kernel.org Cc: gavin.hindman@intel.com Cc: jithu.joseph@intel.com Cc: dave.hansen@intel.com Cc: hpa@zytor.com Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/6486385d1f30336e9973b24c8c65f5079543d3d3.1537377064.git.reinette.chatre@intel.com Signed-off-by: Greg Kroah-Hartman --- kernel/events/core.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/kernel/events/core.c b/kernel/events/core.c index 812ebf1cbb87..4dbce29a9313 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -3757,6 +3757,12 @@ 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 -- 2.20.1