From 4e72f13d58c4245c177a9d5f54579345554f354d Mon Sep 17 00:00:00 2001 From: Hans Verkuil Date: Mon, 29 Jun 2026 08:47:05 +0200 Subject: [PATCH] media: v4l2-async: Unregister sub-device if asc_list is empty When my em28xx USB device that uses the i2c tvp5150 driver is disconnected, it crashes. The cause is that the tvp5150 i2c module uses v4l2_async, but the em28xx driver does not since it predates v4l2_async. In that corner case sd->asc_list is empty, so v4l2_async_unregister_subdev() never calls v4l2_device_unregister_subdev(). Modify the code so that, if sd->asc_list is empty, v4l2_device_unregister_subdev() is still called. Fixes: 28a1295795d8 ("media: v4l: async: Allow multiple connections between entities") Signed-off-by: Hans Verkuil Acked-by: Sakari Ailus Tested-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- drivers/media/v4l2-core/v4l2-async.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core/v4l2-async.c index 888a2e213b08..f36d60e6ff41 100644 --- a/drivers/media/v4l2-core/v4l2-async.c +++ b/drivers/media/v4l2-core/v4l2-async.c @@ -898,9 +898,18 @@ void v4l2_async_unregister_subdev(struct v4l2_subdev *sd) sd->subdev_notifier = NULL; if (sd->asc_list.next) { - list_for_each_entry_safe(asc, asc_tmp, &sd->asc_list, - asc_subdev_entry) { - v4l2_async_unbind_subdev_one(asc->notifier, asc); + if (list_empty(&sd->asc_list)) { + /* + * If the sub-device was registered through other means + * than v4l2-async, there are no async connections but + * the sub-device may still well be registered. + * Unregister it now. + */ + v4l2_device_unregister_subdev(sd); + } else { + list_for_each_entry_safe(asc, asc_tmp, &sd->asc_list, + asc_subdev_entry) + v4l2_async_unbind_subdev_one(asc->notifier, asc); } }