ARM: 7698/1: perf: fix group validation when using enable_on_exec

commit cb2d8b342aa084d1f3ac29966245dec9163677fb upstream.

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.

Reported-by: Sudeep KarkadaNagesha <Sudeep.KarkadaNagesha@arm.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c
index f9e8657dd24122cf67362e4def103d41cfd25329..23fa6a21e228d15da6698d41a3bff2aae63ff5b9 100644 (file)
--- a/arch/arm/kernel/perf_event.c
+++ b/arch/arm/kernel/perf_event.c
@@ -261,7 +261,10 @@ 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;