1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/char/ip27-rtc.c b/drivers/char/ip27-rtc.c
index 86e6538a77b0..ec9d0443d92c 100644
--- a/drivers/char/ip27-rtc.c
+++ b/drivers/char/ip27-rtc.c
@@ -27,6 +27,7 @@
 #include <linux/bcd.h>
 #include <linux/module.h>
 #include <linux/kernel.h>
+#include <linux/smp_lock.h>
 #include <linux/types.h>
 #include <linux/miscdevice.h>
 #include <linux/ioport.h>
@@ -163,15 +164,18 @@ static long rtc_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 
 static int rtc_open(struct inode *inode, struct file *file)
 {
+        lock_kernel();
         spin_lock_irq(&rtc_lock);
 
         if (rtc_status & RTC_IS_OPEN) {
                 spin_unlock_irq(&rtc_lock);
+                unlock_kernel();
                 return -EBUSY;
         }
 
         rtc_status |= RTC_IS_OPEN;
         spin_unlock_irq(&rtc_lock);
+        unlock_kernel();
 
         return 0;
 }