Merge tag 'topic/atomic-core-2015-01-05' of git://anongit.freedesktop.org/drm-intel...

[firefly-linux-kernel-4.4.55.git] / drivers / tty / tty_ldisc.c

diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c
index b66a81d0549e3171420ae948ec3a24ef74987836..3737f55272d2c1184463edc3714f89fb2724730e 100644 (file)
--- a/drivers/tty/tty_ldisc.c
+++ b/drivers/tty/tty_ldisc.c
@@ -572,8 +572,11 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc)
                tty_ldisc_restore(tty, old_ldisc);
        }
 
-       if (tty->ldisc->ops->num != old_ldisc->ops->num && tty->ops->set_ldisc)
+       if (tty->ldisc->ops->num != old_ldisc->ops->num && tty->ops->set_ldisc) {
+               down_read(&tty->termios_rwsem);
                tty->ops->set_ldisc(tty);
+               up_read(&tty->termios_rwsem);
+       }
 
        /* At this point we hold a reference to the new ldisc and a
           reference to the old ldisc, or we hold two references to