[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: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 3 insertions, 1 deletions

diff --git a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c
index 008c74526fd3..da6fbae8df91 100644
--- a/arch/s390/kernel/process.c
+++ b/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();