ARM: perf: fix group validation when using enable_on_exec

Events may be created with attr->disabled == 1 and attr->enable_on_exec
== 1, which confuses the group validation code because events with the
PERF_EVENT_STATE_OFF are not considered candidates for scheduling, which
may lead to failure at group scheduling time.

This patch fixes the validation check for ARM, so that events in the
OFF state are still considered when enable_on_exec is true.

Cc: stable@vger.kernel.org
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Jiri Olsa <jolsa@redhat.com>
Reported-by: Sudeep KarkadaNagesha <Sudeep.KarkadaNagesha@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c
index 146157dfe27c6c991b8507c2c3f248d810754cc0..8c3094d0f7b78426e367e2cf3ed538e54d686cbd 100644 (file)
--- a/arch/arm/kernel/perf_event.c
+++ b/arch/arm/kernel/perf_event.c
@@ -253,7 +253,10 @@ validate_event(struct pmu_hw_events *hw_events,
        struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
        struct pmu *leader_pmu = event->group_leader->pmu;
 
-       if (event->pmu != leader_pmu || event->state <= PERF_EVENT_STATE_OFF)
+       if (event->pmu != leader_pmu || event->state < PERF_EVENT_STATE_OFF)
+               return 1;
+
+       if (event->state == PERF_EVENT_STATE_OFF && !event->attr.enable_on_exec)
                return 1;
 
        return armpmu->get_event_idx(hw_events, event) >= 0;