1 files changed, 4 insertions, 0 deletions

diff --git a/arch/m68k/mvme16x/rtc.c b/arch/m68k/mvme16x/rtc.c
index e341387787ab..432a9f13b2ed 100644
--- a/arch/m68k/mvme16x/rtc.c
+++ b/arch/m68k/mvme16x/rtc.c
@@ -10,6 +10,7 @@
 #include <linux/errno.h>
 #include <linux/miscdevice.h>
 #include <linux/slab.h>
+#include <linux/smp_lock.h>
 #include <linux/ioport.h>
 #include <linux/capability.h>
 #include <linux/fcntl.h>
@@ -127,11 +128,14 @@ static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 
 static int rtc_open(struct inode *inode, struct file *file)
 {
+        lock_kernel();
         if( !atomic_dec_and_test(&rtc_ready) )
         {
                 atomic_inc( &rtc_ready );
+                unlock_kernel();
                 return -EBUSY;
         }
+        unlock_kernel();
 
         return 0;
 }