From 896d81fefe5d1919537db2c2150ab6384e4a6610 Mon Sep 17 00:00:00 2001
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: Wed, 29 Mar 2017 07:50:49 +0200
Subject: [PATCH] Revert "tty: Fix ldisc crash on reopened tty"

This reverts commit 71472fa9c52b1da27663c275d416d8654b905f05.  It caused
merge issues, and Dmitry found some review issues.

Reported-by: Dmitry Vyukov <dvyukov@google.com>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: Michael Neuling <mikey@neuling.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/tty/tty_ldisc.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c
index 4ee7742..68947f6 100644
--- a/drivers/tty/tty_ldisc.c
+++ b/drivers/tty/tty_ldisc.c
@@ -669,17 +669,16 @@ int tty_ldisc_reinit(struct tty_struct *tty, int disc)
 		tty_ldisc_put(tty->ldisc);
 	}
 
+	/* switch the line discipline */
+	tty->ldisc = ld;
 	tty_set_termios_ldisc(tty, disc);
-	retval = tty_ldisc_open(tty, ld);
+	retval = tty_ldisc_open(tty, tty->ldisc);
 	if (retval) {
 		if (!WARN_ON(disc == N_TTY)) {
-			tty_ldisc_put(ld);
-			ld = NULL;
+			tty_ldisc_put(tty->ldisc);
+			tty->ldisc = NULL;
 		}
 	}
-
-	/* switch the line discipline */
-	smp_store_release(&tty->ldisc, ld);
 	return retval;
 }
 
-- 
2.7.4