linux-kernel - [PATCH] media: fix null pointer dereference in v4l_vb2q_enable_media

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Date:	Thu,  3 Mar 2016 19:24:58 -0700
From:	Shuah Khan <shuahkh@....samsung.com>
To:	mchehab@....samsung.com, olli.salonen@....fi
Cc:	Shuah Khan <shuahkh@....samsung.com>, linux-media@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] media: fix null pointer dereference in v4l_vb2q_enable_media_source()

Fix the null pointer dereference in v4l_vb2q_enable_media_source().
DVB only drivers don't have valid struct v4l2_fh pointer.

[  548.443272] BUG: unable to handle kernel NULL pointer dereference
at 0000000000000010
[  548.452036] IP: [<ffffffffc020ffc9>]
v4l_vb2q_enable_media_source+0x9/0x50 [videodev]
[  548.460792] PGD b820e067 PUD bb3df067 PMD 0
[  548.465582] Oops: 0000 [#1] SMP

Signed-off-by: Shuah Khan <shuahkh@....samsung.com>
Reported-by: Olli Salonen <olli.salonen@....fi>
---
 drivers/media/v4l2-core/v4l2-mc.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/media/v4l2-core/v4l2-mc.c b/drivers/media/v4l2-core/v4l2-mc.c
index 643686d..a39a3cd 100644
--- a/drivers/media/v4l2-core/v4l2-mc.c
+++ b/drivers/media/v4l2-core/v4l2-mc.c
@@ -214,6 +214,8 @@ int v4l_vb2q_enable_media_source(struct vb2_queue *q)
 {
 	struct v4l2_fh *fh = q->owner;
 
-	return v4l_enable_media_source(fh->vdev);
+	if (fh && fh->vdev)
+		return v4l_enable_media_source(fh->vdev);
+	return 0;
 }
 EXPORT_SYMBOL_GPL(v4l_vb2q_enable_media_source);
-- 
2.5.0