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media: atomisp: Fix deadlock when the /dev/video# node is closed while still streaming

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atomisp_release() was taking pipe->vb_queue_mutex + isp->mutex at the
same time. But if the /dev/video# node is closed while still streaming
then vb2_queue_release() will call atomisp_stop_streaming() which takes
isp->mutex itself, leading to a deadlock.

To fix this only take isp->mutex after cleaning up the v4l2_fh /
the vb2_queue. While at it switch to vb2_fop_release() which will take
pipe->vb_queue_mutex for us, which also resolves a FIXME comment.

Reviewed-by: Andy Shevchenko <andy@kernel.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
This commit is contained in:
Hans de Goede 2022-10-23 21:22:14 +01:00 committed by Mauro Carvalho Chehab
parent ac8dd062aa
commit da0dd507fa
1 changed files with 5 additions and 16 deletions
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21
drivers/staging/media/atomisp/pci/atomisp_fops.c
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@ -860,23 +860,14 @@ static int atomisp_release(struct file *file)
v4l2_fh_init(&fh.vfh, vdev);
mutex_lock(&pipe->vb_queue_mutex);
mutex_lock(&isp->mutex);
dev_dbg(isp->dev, "release device %s\n", vdev->name);
asd->subdev.devnode = vdev;
/*
* FIXME This if is copied from _vb2_fop_release, this cannot use that
* because that calls v4l2_fh_release() earlier then this function.
* Maybe we can release the fh earlier though, it does not look like
* anything needs it after this.
*/
if (file->private_data == vdev->queue->owner) {
vb2_queue_release(vdev->queue);
vdev->queue->owner = NULL;
}
/* Note file must not be used after this! */
vb2_fop_release(file);
mutex_lock(&isp->mutex);
pipe->users--;
if (pipe->users)
@ -939,9 +930,7 @@ done:
V4L2_SEL_TGT_COMPOSE, 0,
&clear_compose);
mutex_unlock(&isp->mutex);
mutex_unlock(&pipe->vb_queue_mutex);
return v4l2_fh_release(file);
return 0;
}
const struct v4l2_file_operations atomisp_fops = {