[PATCH 47/58] arm64: perf: fix event validation for software group leaders

[Kamal Mostafa]

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

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

From: Will Deacon <will.deacon at arm.com>

commit ee7538a008a45050c8f706d38b600f55953169f9 upstream.

This is a port of c95eb3184ea1 ("ARM: 7809/1: perf: fix event validation
for software group leaders") to arm64, which fixes a panic in the arm64
perf backend found as a result of Vince's fuzzing tool.

Signed-off-by: Will Deacon <will.deacon at arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas at arm.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 arch/arm64/kernel/perf_event.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c
index 8a724a1..34e1bca 100644
--- a/arch/arm64/kernel/perf_event.c
+++ b/arch/arm64/kernel/perf_event.c
@@ -322,6 +322,9 @@ 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 (is_software_event(event))
+		return 1;
+
 	if (event->pmu != leader_pmu || event->state <= PERF_EVENT_STATE_OFF)
 		return 1;
 
-- 
1.8.1.2