[PATCH] tty: Fix UML console breakage

[Peter Hurley]

User-Mode Linux supplies an alternate TTY_MAJOR driver for stdio console,
so the noctty check in tty_open() must apply only to VT driver tty0
devnode and not the UML console driver tty0 devnode.

Fixes: 11e1d4aa4da1 ("tty: Consolidate noctty checks in tty_open()")
Reported-by: Richard Weinberger <richard.weinberger@xxxxxxxxx>
Signed-off-by: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>
---
 drivers/tty/tty_io.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 608beb6..6931df3 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -2158,7 +2158,7 @@ retry_open:
 	read_lock(&tasklist_lock);
 	spin_lock_irq(&current->sighand->siglock);
 	noctty = (filp->f_flags & O_NOCTTY) ||
-			device == MKDEV(TTY_MAJOR, 0) ||
+			(IS_ENABLED(CONFIG_VT) && device == MKDEV(TTY_MAJOR, 0)) ||
 			device == MKDEV(TTYAUX_MAJOR, 1) ||
 			(tty->driver->type == TTY_DRIVER_TYPE_PTY &&
 			 tty->driver->subtype == PTY_TYPE_MASTER);
-- 
2.8.0