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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Hans Verkuil <hverkuil-cisco@xs4all.nl>,
        Nicolas Dufresne <nicolas@ndufresne.ca>,
        Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Subject: [PATCH 4.19 51/86] media: v4l2-mem2mem.c: fix broken links
Date:   Tue, 10 Mar 2020 13:45:15 +0100
Message-Id: <20200310124533.550507720@linuxfoundation.org>
In-Reply-To: <20200310124530.808338541@linuxfoundation.org>
References: <20200310124530.808338541@linuxfoundation.org>
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From: Hans Verkuil <hverkuil-cisco@xs4all.nl>

commit 316e730f1d8bb029fe6cec2468fb2a50424485b3 upstream.

The topology that v4l2_m2m_register_media_controller() creates for a
processing block actually created a source-to-source link and a sink-to-sink
link instead of two source-to-sink links.

Unfortunately v4l2-compliance never checked for such bad links, so this
went unreported for quite some time.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Reported-by: Nicolas Dufresne <nicolas@ndufresne.ca>
Cc: <stable@vger.kernel.org>      # for v4.19 and up
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/media/v4l2-core/v4l2-mem2mem.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/media/v4l2-core/v4l2-mem2mem.c
+++ b/drivers/media/v4l2-core/v4l2-mem2mem.c
@@ -787,12 +787,12 @@ int v4l2_m2m_register_media_controller(s
 		goto err_rel_entity1;
 
 	/* Connect the three entities */
-	ret = media_create_pad_link(m2m_dev->source, 0, &m2m_dev->proc, 1,
+	ret = media_create_pad_link(m2m_dev->source, 0, &m2m_dev->proc, 0,
 			MEDIA_LNK_FL_IMMUTABLE | MEDIA_LNK_FL_ENABLED);
 	if (ret)
 		goto err_rel_entity2;
 
-	ret = media_create_pad_link(&m2m_dev->proc, 0, &m2m_dev->sink, 0,
+	ret = media_create_pad_link(&m2m_dev->proc, 1, &m2m_dev->sink, 0,
 			MEDIA_LNK_FL_IMMUTABLE | MEDIA_LNK_FL_ENABLED);
 	if (ret)
 		goto err_rm_links0;