[media] V4L: sh_mobile_ceu_camera: fix Oops when USERPTR mapping fails

If vb2_dma_contig_get_userptr() fails on a videobuffer, driver's
.buf_init() method will not be called and the list will not be
initialised. Trying to remove an uninitialised element from a list leads
to a NULL-dereference.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Tested-by: Bastian Hecht <hechtb@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 6 insertions, 2 deletions

diff --git a/drivers/media/video/sh_mobile_ceu_camera.c b/drivers/media/video/sh_mobile_ceu_camera.c
index f86550703f8e..e54089802b6b 100644
--- a/drivers/media/video/sh_mobile_ceu_camera.c
+++ b/drivers/media/video/sh_mobile_ceu_camera.c
@@ -422,8 +422,12 @@ static void sh_mobile_ceu_videobuf_release(struct vb2_buffer *vb)
                 pcdev->active = NULL;
         }
 
-        /* Doesn't hurt also if the list is empty */
-        list_del_init(&buf->queue);
+        /*
+         * Doesn't hurt also if the list is empty, but it hurts, if queuing the
+         * buffer failed, and .buf_init() hasn't been called
+         */
+        if (buf->queue.next)
+                list_del_init(&buf->queue);
 
         spin_unlock_irq(&pcdev->lock);
 }