linux-kernel - [PATCHv6 4/7] tty: Simplify tty->count math in tty

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20181101002452.5483-5-dima@arista.com>
Date:   Thu,  1 Nov 2018 00:24:49 +0000
From:   Dmitry Safonov <dima@...sta.com>
To:     linux-kernel@...r.kernel.org
Cc:     Dmitry Safonov <0x7f454c46@...il.com>,
        Dmitry Safonov <dima@...sta.com>,
        Daniel Axtens <dja@...ens.net>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        Mark Rutland <mark.rutland@....com>,
        Michael Neuling <mikey@...ling.org>,
        Mikulas Patocka <mpatocka@...hat.com>,
        Nathan March <nathan@...net>,
        Pasi Kärkkäinen <pasik@....fi>,
        Peter Hurley <peter@...leysoftware.com>,
        Peter Zijlstra <peterz@...radead.org>,
        "Rong, Chen" <rong.a.chen@...el.com>,
        Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>,
        Tan Xiaojun <tanxiaojun@...wei.com>,
        Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>,
        Jiri Slaby <jslaby@...e.com>, Jiri Slaby <jslaby@...e.cz>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: [PATCHv6 4/7] tty: Simplify tty->count math in tty_reopen()

As notted by Jiri, tty_ldisc_reinit() shouldn't rely on tty counter.
Simplify math by increasing the counter after reinit success.

Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: Jiri Slaby <jslaby@...e.com>
Link: lkml.kernel.org/r/<20180829022353.23568-2-dima@...sta.com>
Suggested-by: Jiri Slaby <jslaby@...e.com>
Reviewed-by: Jiri Slaby <jslaby@...e.cz>
Tested-by: Mark Rutland <mark.rutland@....com>
Signed-off-by: Dmitry Safonov <dima@...sta.com>
---
 drivers/tty/tty_io.c | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index f73d8fa7f02b..57d06eda5b2f 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -1272,16 +1272,13 @@ static int tty_reopen(struct tty_struct *tty)
 	if (retval)
 		return retval;
 
-	tty->count++;
-	if (tty->ldisc)
-		goto out_unlock;
+	if (!tty->ldisc)
+		retval = tty_ldisc_reinit(tty, tty->termios.c_line);
+	tty_ldisc_unlock(tty);
 
-	retval = tty_ldisc_reinit(tty, tty->termios.c_line);
-	if (retval)
-		tty->count--;
+	if (retval == 0)
+		tty->count++;
 
-out_unlock:
-	tty_ldisc_unlock(tty);
 	return retval;
 }
 
-- 
2.19.1