1 files changed, 8 insertions, 4 deletions

diff --git a/drivers/s390/char/fs3270.c b/drivers/s390/char/fs3270.c
index 78f8bda81dae..ef205ddd31a4 100644
--- a/drivers/s390/char/fs3270.c
+++ b/drivers/s390/char/fs3270.c
@@ -424,11 +424,15 @@ fs3270_open(struct inode *inode, struct file *filp)
         minor = iminor(filp->f_dentry->d_inode);
         /* Check for minor 0 multiplexer. */
         if (minor == 0) {
-                if (!current->signal->tty)
+                struct tty_struct *tty;
+                mutex_lock(&tty_mutex);
+                tty = get_current_tty();
+                if (!tty || tty->driver->major != IBM_TTY3270_MAJOR) {
+                        mutex_unlock(&tty_mutex);
                         return -ENODEV;
-                if (current->signal->tty->driver->major != IBM_TTY3270_MAJOR)
-                        return -ENODEV;
-                minor = current->signal->tty->index + RAW3270_FIRSTMINOR;
+                }
+                minor = tty->index + RAW3270_FIRSTMINOR;
+                mutex_unlock(&tty_mutex);
         }
         /* Check if some other program is already using fullscreen mode. */
         fp = (struct fs3270 *) raw3270_find_view(&fs3270_fn, minor);