[media] v4l2-ctrls.c: add NULL check

Check that the control whose events we want to delete is still there.

Normally this will always be the case, but I am not 100% certain if
there aren't any corner cases when a device is forcibly unbound.

In any case, this will satisfy static checkers and simply make it more
robust.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Reported-by: Shaobo <shaobo@cs.utah.edu>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c
index 47001e25fd9e..b9e08e3d6e0e 100644
--- a/drivers/media/v4l2-core/v4l2-ctrls.c
+++ b/drivers/media/v4l2-core/v4l2-ctrls.c
@@ -3367,6 +3367,9 @@ static void v4l2_ctrl_del_event(struct v4l2_subscribed_event *sev)
 {
         struct v4l2_ctrl *ctrl = v4l2_ctrl_find(sev->fh->ctrl_handler, sev->id);
 
+        if (ctrl == NULL)
+                return;
+
         v4l2_ctrl_lock(ctrl);
         list_del(&sev->node);
         v4l2_ctrl_unlock(ctrl);