1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/s390/char/vmcp.c b/drivers/s390/char/vmcp.c
index 2f419b0ea628..bf3dc6e0e33a 100644
--- a/drivers/s390/char/vmcp.c
+++ b/drivers/s390/char/vmcp.c
@@ -16,6 +16,7 @@
 #include <linux/kernel.h>
 #include <linux/miscdevice.h>
 #include <linux/module.h>
+#include <linux/smp_lock.h>
 #include <asm/cpcmd.h>
 #include <asm/debug.h>
 #include <asm/uaccess.h>
@@ -39,11 +40,14 @@ static int vmcp_open(struct inode *inode, struct file *file)
         session = kmalloc(sizeof(*session), GFP_KERNEL);
         if (!session)
                 return -ENOMEM;
+
+        lock_kernel();
         session->bufsize = PAGE_SIZE;
         session->response = NULL;
         session->resp_size = 0;
         mutex_init(&session->mutex);
         file->private_data = session;
+        unlock_kernel();
         return nonseekable_open(inode, file);
 }