From da5a0fc6743df9b5a3e9f915a1ed16f45465d529 Mon Sep 17 00:00:00 2001
From: Peter Hurley <peter@hurleysoftware.com>
Date: Thu, 31 Mar 2016 17:05:30 -0700
Subject: tty: Fix UML console breakage

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@gmail.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 8d26ed7..876878a 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);
-- 
cgit v0.10.2


From 5e00bbfbc5ec21e87d24e206bba9fc2cbe6631a1 Mon Sep 17 00:00:00 2001
From: Peter Hurley <peter@hurleysoftware.com>
Date: Thu, 31 Mar 2016 17:47:07 -0700
Subject: tty: Fix merge of "tty: Refactor tty_open()"

Commit e9036d066236 ("tty: Drop krefs for interrupted tty lock")
fixed a tty reference counting problem introduced in
commit 0bfd464d3fdd ("tty: Wait interruptibly for tty lock on reopen"),
so v4.5.0 is correct.

However, commit d6203d0c7b73 ("tty: Refactor tty_open()") moved the
relevant code for 4.6-rc1; correct the merge.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 876878a..9b04d72 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -2049,14 +2049,13 @@ static struct tty_struct *tty_open_by_driver(dev_t device, struct inode *inode,
 	if (tty) {
 		mutex_unlock(&tty_mutex);
 		retval = tty_lock_interruptible(tty);
+		tty_kref_put(tty);  /* drop kref from tty_driver_lookup_tty() */
 		if (retval) {
 			if (retval == -EINTR)
 				retval = -ERESTARTSYS;
 			tty = ERR_PTR(retval);
 			goto out;
 		}
-		/* safe to drop the kref from tty_driver_lookup_tty() */
-		tty_kref_put(tty);
 		retval = tty_reopen(tty);
 		if (retval < 0) {
 			tty_unlock(tty);
-- 
cgit v0.10.2