1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index 41fe8a047d37..fe9d129c8735 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -2353,8 +2353,12 @@ static ssize_t n_tty_write(struct tty_struct *tty, struct file *file,
                         if (tty->ops->flush_chars)
                                 tty->ops->flush_chars(tty);
                 } else {
+                        struct n_tty_data *ldata = tty->disc_data;
+
                         while (nr > 0) {
+                                mutex_lock(&ldata->output_lock);
                                 c = tty->ops->write(tty, b, nr);
+                                mutex_unlock(&ldata->output_lock);
                                 if (c < 0) {
                                         retval = c;
                                         goto break_out;