1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/s390/char/monreader.c b/drivers/s390/char/monreader.c
index f0e4c96afbf8..35fd8dfcaaa6 100644
--- a/drivers/s390/char/monreader.c
+++ b/drivers/s390/char/monreader.c
@@ -10,6 +10,7 @@
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/init.h>
+#include <linux/smp_lock.h>
 #include <linux/errno.h>
 #include <linux/types.h>
 #include <linux/kernel.h>
@@ -291,6 +292,7 @@ static int mon_open(struct inode *inode, struct file *filp)
         /*
          * only one user allowed
          */
+        lock_kernel();
         rc = -EBUSY;
         if (test_and_set_bit(MON_IN_USE, &mon_in_use))
                 goto out;
@@ -327,6 +329,7 @@ static int mon_open(struct inode *inode, struct file *filp)
                 goto out_path;
         }
         filp->private_data = monpriv;
+        unlock_kernel();
         return nonseekable_open(inode, filp);
 
 out_path:
@@ -336,6 +339,7 @@ out_priv:
 out_use:
         clear_bit(MON_IN_USE, &mon_in_use);
 out:
+        unlock_kernel();
         return rc;
 }