[PATCH] s390: fix preempt_count of idle thread with cpu hotplug

Set preempt_count of idle_thread to zero before switching off cpu.  Otherwise
the preempt_count will be wrong if the cpu is switched on again since the
thread will be reused.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

arch/s390/kernel/process.c

@@ -128,8 +128,10 @@ void default_idle(void)
 	__ctl_set_bit(8, 15);
 
 #ifdef CONFIG_HOTPLUG_CPU
-	if (cpu_is_offline(cpu))
+	if (cpu_is_offline(cpu)) {
+		preempt_enable_no_resched();
 		cpu_die();
+	}
 #endif
 
 	local_mcck_disable();