From: Darrick J. Wong <darrick.wong@oracle.com>
Date: Fri, 10 May 2013 22:40:13 +0000 (-0700)
Subject: ttyprintk: Fix NULL pointer deref by setting tty_port ops after initializing port
X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=b5325a02aa84c794cf520d6d68cae4b150988a32;p=sagit-ice-cold%2Fkernel_xiaomi_msm8998.git

ttyprintk: Fix NULL pointer deref by setting tty_port ops after initializing port

tty_port_init() zeroes out the tty port, which means that we have to set the
ops pointer /after/, not before this call.  Otherwise, tty_port_open will crash
when it tries to deref ops, which is now a NULL pointer.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/char/ttyprintk.c b/drivers/char/ttyprintk.c
index 4945bd3d18d0..d5d2e4a985aa 100644
--- a/drivers/char/ttyprintk.c
+++ b/drivers/char/ttyprintk.c
@@ -179,7 +179,6 @@ static int __init ttyprintk_init(void)
 {
 	int ret = -ENOMEM;
 
-	tpk_port.port.ops = &null_ops;
 	mutex_init(&tpk_port.port_write_mutex);
 
 	ttyprintk_driver = tty_alloc_driver(1,
@@ -190,6 +189,7 @@ static int __init ttyprintk_init(void)
 		return PTR_ERR(ttyprintk_driver);
 
 	tty_port_init(&tpk_port.port);
+	tpk_port.port.ops = &null_ops;
 
 	ttyprintk_driver->driver_name = "ttyprintk";
 	ttyprintk_driver->name = "ttyprintk";