V4L/DVB (7891): cx18/ivtv: fix open() kernel oops

Upon error conditions in cx18/ivtv_probe(), the code at the 'err:' label
leaves a NULL entry in cx18/ivtv_cards[]. This can cause a NULL pointer
de-reference in cx18/ivtv_v4l2_open() which is fixed by this patch.

Signed-off-by: Andy Walls <awalls@radix.net>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/media/video/ivtv/ivtv-fileops.c b/drivers/media/video/ivtv/ivtv-fileops.c
index 2b74b0ab147..f2fa434b677 100644
--- a/drivers/media/video/ivtv/ivtv-fileops.c
+++ b/drivers/media/video/ivtv/ivtv-fileops.c
@@ -987,6 +987,8 @@ int ivtv_v4l2_open(struct inode *inode, struct file *filp)
         /* Find which card this open was on */
         spin_lock(&ivtv_cards_lock);
         for (x = 0; itv == NULL && x < ivtv_cards_active; x++) {
+                if (ivtv_cards[x] == NULL)
+                        continue;
                 /* find out which stream this open was on */
                 for (y = 0; y < IVTV_MAX_STREAMS; y++) {
                         s = &ivtv_cards[x]->streams[y];