Patch "[media] v4l: vsp1: Prevent pipelines from running when not streaming" has been added to the 4.8-stable tree

Patch "[media] v4l: vsp1: Prevent pipelines from running when not streaming" has been added to the 4.8-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    [media] v4l: vsp1: Prevent pipelines from running when not streaming

to the 4.8-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     v4l-vsp1-prevent-pipelines-from-running-when-not-streaming.patch
and it can be found in the queue-4.8 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From e4e70a147a48618a36ae1b81c641516cb9d45993 Mon Sep 17 00:00:00 2001
From: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Date: Fri, 8 Jul 2016 06:20:51 -0300
Subject: [media] v4l: vsp1: Prevent pipelines from running when not streaming

From: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

commit e4e70a147a48618a36ae1b81c641516cb9d45993 upstream.

Pipelines can only be run if all their video nodes are streaming. Commit
b4dfb9b35a19 ("[media] v4l: vsp1: Stop the pipeline upon the first
STREAMOFF") fixed the pipeline stop sequence, but introduced a race
condition that makes it possible to run a pipeline after stopping the
stream on a video node by queuing a buffer on the other side of the
pipeline.

Fix this by clearing the buffers ready flag when stopping the stream,
which will prevent the QBUF handler from running the pipeline.

Fixes: b4dfb9b35a19 ("[media] v4l: vsp1: Stop the pipeline upon the first STREAMOFF")

Reported-by: Kieran Bingham <kieran@bingham.xyz>
Tested-by: Kieran Bingham <kieran@bingham.xyz>
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/media/platform/vsp1/vsp1_video.c |    7 +++++++
 1 file changed, 7 insertions(+)

--- a/drivers/media/platform/vsp1/vsp1_video.c
+++ b/drivers/media/platform/vsp1/vsp1_video.c
@@ -675,6 +675,13 @@ static void vsp1_video_stop_streaming(st
 	unsigned long flags;
 	int ret;
 
+	/* Clear the buffers ready flag to make sure the device won't be started
+	 * by a QBUF on the video node on the other side of the pipeline.
+	 */
+	spin_lock_irqsave(&video->irqlock, flags);
+	pipe->buffers_ready &= ~(1 << video->pipe_index);
+	spin_unlock_irqrestore(&video->irqlock, flags);
+
 	mutex_lock(&pipe->lock);
 	if (--pipe->stream_count == pipe->num_inputs) {
 		/* Stop the pipeline. */


Patches currently in stable-queue which might be from laurent.pinchart+renesas@ideasonboard.com are

queue-4.8/v4l-vsp1-prevent-pipelines-from-running-when-not-streaming.patch