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 186c8cb982c543a2cc1631796b34376151b33702..85d63329769e75f5039892ee889b818fd5615e93 100644 (file)
--- a/arch/arm/kernel/perf_event.c
+++ b/arch/arm/kernel/perf_event.c
@@ -319,7 +319,10 @@ validate_event(struct pmu_hw_events *hw_events,
        struct hw_perf_event fake_event = event->hw;
        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, &fake_event) >= 0;