From cc6eddcd37ce6be403b5820ffd84cb84b33b653f Mon Sep 17 00:00:00 2001 From: Hans Verkuil Date: Mon, 21 May 2018 04:54:34 -0400 Subject: media: v4l2-dev: lock req_queue_mutex We need to serialize streamon/off with queueing new requests. These ioctls may trigger the cancellation of a streaming operation, and that should not be mixed with queuing a new request at the same time. Finally close() needs this lock since that too can trigger the cancellation of a streaming operation. We take the req_queue_mutex here before any other locks since it is a very high-level lock. Signed-off-by: Hans Verkuil Signed-off-by: Sakari Ailus Reviewed-by: Mauro Carvalho Chehab Signed-off-by: Mauro Carvalho Chehab --- drivers/media/v4l2-core/v4l2-dev.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) (limited to 'drivers/media/v4l2-core/v4l2-dev.c') diff --git a/drivers/media/v4l2-core/v4l2-dev.c b/drivers/media/v4l2-core/v4l2-dev.c index 69e775930fc4..feb749aaaa42 100644 --- a/drivers/media/v4l2-core/v4l2-dev.c +++ b/drivers/media/v4l2-core/v4l2-dev.c @@ -444,8 +444,22 @@ static int v4l2_release(struct inode *inode, struct file *filp) struct video_device *vdev = video_devdata(filp); int ret = 0; - if (vdev->fops->release) - ret = vdev->fops->release(filp); + /* + * We need to serialize the release() with queueing new requests. + * The release() may trigger the cancellation of a streaming + * operation, and that should not be mixed with queueing a new + * request at the same time. + */ + if (vdev->fops->release) { + if (v4l2_device_supports_requests(vdev->v4l2_dev)) { + mutex_lock(&vdev->v4l2_dev->mdev->req_queue_mutex); + ret = vdev->fops->release(filp); + mutex_unlock(&vdev->v4l2_dev->mdev->req_queue_mutex); + } else { + ret = vdev->fops->release(filp); + } + } + if (vdev->dev_debug & V4L2_DEV_DEBUG_FOP) dprintk("%s: release\n", video_device_node_name(vdev)); -- cgit v1.2.3