From: Mauro Carvalho Chehab <m.chehab@samsung.com>
Date: Wed, 3 Sep 2014 17:32:26 +0000 (-0300)
Subject: dmxdev: don't use before checking file->private_data
X-Git-Tag: accepted/tizen/common/20141215.134117~7
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=687e6ad9f5edd1c91a75532d4996bcb613a85f29;p=platform%2Fkernel%2Flinux-3.10.git

dmxdev: don't use before checking file->private_data

As reported by smatch:
	drivers/media/dvb-core/dmxdev.c:1091 dvb_demux_poll() warn: variable dereferenced before check 'dmxdevfilter' (see line 1088)

This was introduced by changeset d102cac8097c.

We need to test before using it.

Change-Id: I4e51d508c466b915338bd0a88a7afb49f4dbeb4d
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
Signed-off-by: Changbing Xiong <cb.xiong@samsung.com>
---

diff --git a/drivers/media/dvb-core/dmxdev.c b/drivers/media/dvb-core/dmxdev.c
index 42b5e70..abff803 100644
--- a/drivers/media/dvb-core/dmxdev.c
+++ b/drivers/media/dvb-core/dmxdev.c
@@ -1085,10 +1085,9 @@ static long dvb_demux_ioctl(struct file *file, unsigned int cmd,
 static unsigned int dvb_demux_poll(struct file *file, poll_table *wait)
 {
 	struct dmxdev_filter *dmxdevfilter = file->private_data;
-	struct dmxdev *dmxdev = dmxdevfilter->dev;
 	unsigned int mask = 0;
 
-	if ((!dmxdevfilter) || (dmxdev->exit))
+	if ((!dmxdevfilter) || dmxdevfilter->dev->exit)
 		return POLLERR;
 
 	poll_wait(file, &dmxdevfilter->buffer.queue, wait);