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Date: Wed, 21 Jul 2004 18:45:47 +0400
From: "Vladimir B. Savkin" <master@sectorb.msk.ru>
To: linux-kernel@vger.kernel.org
Subject: UNIX98 pty indices leak
Message-ID: <20040721144546.GA9740@tentacle.sectorb.msk.ru>
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X-Organization: Moscow State Univ., Dept. of Mechanics and Mathematics
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Hello!

I noticed that our PPPoE/PPtP access concentrator leaks pty devices.
When all 4096 indices are leaked, there was need to reboot it.

The following patch fixes this problem (tested on 2.6.7-mm7,
but applies cleanly to 2.6.8-rc2).

--- tmp/linux-2.6.7/drivers/char/tty_io.c	Wed Jul 21 17:47:18 2004
+++ linux-2.6.7/drivers/char/tty_io.c	Wed Jul 21 17:54:33 2004
@@ -1060,7 +1060,7 @@
 {
 	struct tty_struct *tty, *o_tty;
 	int	pty_master, tty_closing, o_tty_closing, do_sleep;
-	int	devpts_master;
+	int	devpts_master, devpts;
 	int	idx;
 	char	buf[64];
 	
@@ -1075,7 +1075,8 @@
 	idx = tty->index;
 	pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
 		      tty->driver->subtype == PTY_TYPE_MASTER);
-	devpts_master = pty_master && (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM);
+	devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0;
+	devpts_master = pty_master && devpts;
 	o_tty = tty->link;
 
 #ifdef TTY_PARANOIA_CHECK
@@ -1300,7 +1301,7 @@
 
 #ifdef CONFIG_UNIX98_PTYS
 	/* Make this pty number available for reallocation */
-	if (devpts_master) {
+	if (devpts) {
 		down(&allocated_ptys_lock);
 		idr_remove(&allocated_ptys, idx);
 		up(&allocated_ptys_lock);

~
:wq
                                        With best regards, 
                                           Vladimir Savkin.