1 files changed, 7 insertions, 2 deletions

diff --git a/drivers/misc/phantom.c b/drivers/misc/phantom.c
index 71d1c84e2fa8..186162470090 100644
--- a/drivers/misc/phantom.c
+++ b/drivers/misc/phantom.c
@@ -22,6 +22,7 @@
 #include <linux/interrupt.h>
 #include <linux/cdev.h>
 #include <linux/phantom.h>
+#include <linux/smp_lock.h>
 
 #include <asm/atomic.h>
 #include <asm/io.h>
@@ -212,13 +213,17 @@ static int phantom_open(struct inode *inode, struct file *file)
         struct phantom_device *dev = container_of(inode->i_cdev,
                         struct phantom_device, cdev);
 
+        lock_kernel();
         nonseekable_open(inode, file);
 
-        if (mutex_lock_interruptible(&dev->open_lock))
+        if (mutex_lock_interruptible(&dev->open_lock)) {
+                unlock_kernel();
                 return -ERESTARTSYS;
+        }
 
         if (dev->opened) {
                 mutex_unlock(&dev->open_lock);
+                unlock_kernel();
                 return -EINVAL;
         }
 
@@ -229,7 +234,7 @@ static int phantom_open(struct inode *inode, struct file *file)
         atomic_set(&dev->counter, 0);
         dev->opened++;
         mutex_unlock(&dev->open_lock);
-
+        unlock_kernel();
         return 0;
 }