linux-kernel - [ 016/105] [media] au0828: fix case where STREAMOFF being called on stopped stream causes BUG()

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Message-Id: <20121028231541.944810096@decadent.org.uk>
Date:	Sun, 28 Oct 2012 23:15:52 +0000
From:	Ben Hutchings <ben@...adent.org.uk>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:	akpm@...ux-foundation.org, alan@...rguk.ukuu.org.uk,
	Devin Heitmueller <dheitmueller@...nellabs.com>,
	Larry Finger <larry.finger@...inger.net>,
	Jay Harbeston <jharbestonus@...il.com>,
	Mauro Carvalho Chehab <mchehab@...hat.com>
Subject: [ 016/105] [media] au0828: fix case where STREAMOFF being called on stopped
 stream causes BUG()

3.2-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Devin Heitmueller <dheitmueller@...nellabs.com>

commit a595c1ce4c9d572cf53513570b9f1a263d7867f2 upstream.

We weren't checking whether the resource was in use before calling
res_free(), so applications which called STREAMOFF on a v4l2 device that
wasn't already streaming would cause a BUG() to be hit (MythTV).

Reported-by: Larry Finger <larry.finger@...inger.net>
Reported-by: Jay Harbeston <jharbestonus@...il.com>
Signed-off-by: Devin Heitmueller <dheitmueller@...nellabs.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@...hat.com>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 drivers/media/video/au0828/au0828-video.c |   12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/media/video/au0828/au0828-video.c b/drivers/media/video/au0828/au0828-video.c
index df92322..4d5b670 100644
--- a/drivers/media/video/au0828/au0828-video.c
+++ b/drivers/media/video/au0828/au0828-video.c
@@ -1702,14 +1702,18 @@ static int vidioc_streamoff(struct file *file, void *priv,
 			(AUVI_INPUT(i).audio_setup)(dev, 0);
 		}
 
-		videobuf_streamoff(&fh->vb_vidq);
-		res_free(fh, AU0828_RESOURCE_VIDEO);
+		if (res_check(fh, AU0828_RESOURCE_VIDEO)) {
+			videobuf_streamoff(&fh->vb_vidq);
+			res_free(fh, AU0828_RESOURCE_VIDEO);
+		}
 	} else if (fh->type == V4L2_BUF_TYPE_VBI_CAPTURE) {
 		dev->vbi_timeout_running = 0;
 		del_timer_sync(&dev->vbi_timeout);
 
-		videobuf_streamoff(&fh->vb_vbiq);
-		res_free(fh, AU0828_RESOURCE_VBI);
+		if (res_check(fh, AU0828_RESOURCE_VBI)) {
+			videobuf_streamoff(&fh->vb_vbiq);
+			res_free(fh, AU0828_RESOURCE_VBI);
+		}
 	}
 
 	return 0;


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