1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/char/sonypi.c b/drivers/char/sonypi.c
index 58533de59027..85e0eb76eeab 100644
--- a/drivers/char/sonypi.c
+++ b/drivers/char/sonypi.c
@@ -49,6 +49,7 @@
 #include <linux/err.h>
 #include <linux/kfifo.h>
 #include <linux/platform_device.h>
+#include <linux/smp_lock.h>
 
 #include <asm/uaccess.h>
 #include <asm/io.h>
@@ -906,12 +907,14 @@ static int sonypi_misc_release(struct inode *inode, struct file *file)
 
 static int sonypi_misc_open(struct inode *inode, struct file *file)
 {
+        lock_kernel();
         mutex_lock(&sonypi_device.lock);
         /* Flush input queue on first open */
         if (!sonypi_device.open_count)
                 kfifo_reset(sonypi_device.fifo);
         sonypi_device.open_count++;
         mutex_unlock(&sonypi_device.lock);
+        unlock_kernel();
         return 0;
 }