smpboot: fix memory leak on error handling

The cpumask is allocated before threads get created. If the latter step
fails, we need to free the cpumask.
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Reviewed-by: NChris Metcalf <cmetcalf@ezchip.com>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

kernel/smpboot.c

@@ -301,6 +301,7 @@ int smpboot_register_percpu_thread(struct smp_hotplug_thread *plug_thread)
 		ret = __smpboot_create_thread(plug_thread, cpu);
 		if (ret) {
 			smpboot_destroy_threads(plug_thread);
+			free_cpumask_var(plug_thread->cpumask);
 			goto out;
 		}
 		smpboot_unpark_thread(plug_thread, cpu);