1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/sbus/char/rtc.c b/drivers/sbus/char/rtc.c
index 18d18f1a114e..b0429917154d 100644
--- a/drivers/sbus/char/rtc.c
+++ b/drivers/sbus/char/rtc.c
@@ -12,6 +12,7 @@
  */
 
 #include <linux/module.h>
+#include <linux/smp_lock.h>
 #include <linux/types.h>
 #include <linux/errno.h>
 #include <linux/miscdevice.h>
@@ -213,6 +214,7 @@ static int rtc_open(struct inode *inode, struct file *file)
 {
         int ret;
 
+        lock_kernel();
         spin_lock_irq(&mostek_lock);
         if (rtc_busy) {
                 ret = -EBUSY;
@@ -221,6 +223,7 @@ static int rtc_open(struct inode *inode, struct file *file)
                 ret = 0;
         }
         spin_unlock_irq(&mostek_lock);
+        unlock_kernel();
 
         return ret;
 }