[media] 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@osg.samsung.com>
Reported-by: Olli Salonen <olli.salonen@iki.fi>
Tested-by: Olli Salonen <olli.salonen@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

diff --git a/drivers/media/v4l2-core/v4l2-mc.c b/drivers/media/v4l2-core/v4l2-mc.c
index 7291018..f8b6e3b 100644 (file)
--- a/drivers/media/v4l2-core/v4l2-mc.c
+++ b/drivers/media/v4l2-core/v4l2-mc.c
@@ -240,7 +240,9 @@ 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);