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

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

From: Lenny Szubowicz <redacted>

[ Upstream commit 8b29d29abc484d638213dd79a18a95ae7e5bb402 ]

Fix once per second (round_robin_time) memory leak of about 1 KB in
each acpi_pad kernel idling thread that is activated.

Found by testing with kmemleak.

Signed-off-by: Lenny Szubowicz <redacted>
Signed-off-by: Rafael J. Wysocki <redacted>
Signed-off-by: Sasha Levin <redacted>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/acpi/acpi_pad.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/acpi/acpi_pad.c
+++ b/drivers/acpi/acpi_pad.c

@@ -109,6 +109,7 @@ static void round_robin_cpu(unsigned int
 		cpumask_andnot(tmp, cpu_online_mask, pad_busy_cpus);
 	if (cpumask_empty(tmp)) {
 		mutex_unlock(&round_robin_lock);
+		free_cpumask_var(tmp);
 		return;
 	}
 	for_each_cpu(cpu, tmp) {

@@ -126,6 +127,8 @@ static void round_robin_cpu(unsigned int
 	mutex_unlock(&round_robin_lock);
 
 	set_cpus_allowed_ptr(current, cpumask_of(preferred_cpu));
+
+	free_cpumask_var(tmp);
 }
 
 static void exit_round_robin(unsigned int tsk_index)