X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=drivers%2Ftty%2Fn_tty.c;h=6cfe4019abc63b3f3321df606e57bdd38ed6be72;hb=2156eda2aafa0b0f660656246a11d7c2a9947ff9;hp=6c7fe90ad72d48d2834536331e6826ee2719f94f;hpb=bd2931b5cff6a3bf39bfe15fae051fb8229c0029;p=firefly-linux-kernel-4.4.55.git

diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index 6c7fe90ad72d..6cfe4019abc6 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -2066,8 +2066,12 @@ 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;