[PATCH 4.9 49/59] bus: arm-ccn: Prevent hotplug callback leak

[Greg Kroah-Hartman]

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

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

From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

commit 26242b330093fd14c2e94fb6cbdf0f482ab26576 upstream.

In case the driver registration fails, the hotplug callback is leaked.

Not fatal, because it's never invoked as there are no instances registered,
but wrong nevertheless.

Fixes: fdc15a36d84e ("bus/arm-ccn: Convert to hotplug statemachine")
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Pawel Moll <pawel.moll@xxxxxxx>
Cc: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/bus/arm-ccn.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/drivers/bus/arm-ccn.c
+++ b/drivers/bus/arm-ccn.c
@@ -1570,7 +1570,10 @@ static int __init arm_ccn_init(void)
 	for (i = 0; i < ARRAY_SIZE(arm_ccn_pmu_events); i++)
 		arm_ccn_pmu_events_attrs[i] = &arm_ccn_pmu_events[i].attr.attr;
 
-	return platform_driver_register(&arm_ccn_driver);
+	ret = platform_driver_register(&arm_ccn_driver);
+	if (ret)
+		cpuhp_remove_multi_state(CPUHP_AP_PERF_ARM_CCN_ONLINE);
+	return ret;
 }
 
 static void __exit arm_ccn_exit(void)