[076/126] ARM: 7698/1: perf: fix group validation when using enable_on_exec

[Steven Rostedt]

3.6.11.3 stable review patch.
If anyone has any objections, please let me know.

------------------

From: Will Deacon <will.deacon@xxxxxxx>

[ Upstream commit cb2d8b342aa084d1f3ac29966245dec9163677fb ]

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@xxxxxxxxxxxxxxx
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Reported-by: Sudeep KarkadaNagesha <Sudeep.KarkadaNagesha@xxxxxxx>
Signed-off-by: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
 arch/arm/kernel/perf_event.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c
index ab243b8..5770b9d 100644
--- a/arch/arm/kernel/perf_event.c
+++ b/arch/arm/kernel/perf_event.c
@@ -316,7 +316,10 @@ 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;
-- 
1.7.10.4


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