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Commit e84e7a56 authored by Amit Shah's avatar Amit Shah Committed by Rusty Russell
Browse files

virtio: rng: disallow multiple device registrations, fixes crashes 



The code currently only supports one virtio-rng device at a time.
Invoking guests with multiple devices causes the guest to blow up.

Check if we've already registered and initialised the driver.  Also
cleanup in case of registration errors or hot-unplug so that a new
device can be used.

Reported-by: default avatarPeter Krempa <pkrempa@redhat.com>
Reported-by: default avatar <yunzheng@redhat.com>
Signed-off-by: default avatarAmit Shah <amit.shah@redhat.com>
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
Cc: stable@kernel.org
parent f7f154f1

drivers/char/hw_random/virtio-rng.c

+11 −2
Original line number Diff line number Diff line
@@ -92,14 +92,22 @@ static int probe_common(struct virtio_device *vdev) 
{

	int err;



	if (vq) {

		/* We only support one device for now */

		return -EBUSY;

	}

	/* We expect a single virtqueue. */

	vq = virtio_find_single_vq(vdev, random_recv_done, "input");

	if (IS_ERR(vq))

		return PTR_ERR(vq);

	if (IS_ERR(vq)) {

		err = PTR_ERR(vq);

		vq = NULL;

		return err;

	}



	err = hwrng_register(&virtio_hwrng);

	if (err) {

		vdev->config->del_vqs(vdev);

		vq = NULL;

		return err;

	}
@@ -112,6 +120,7 @@ static void remove_common(struct virtio_device *vdev) 
	busy = false;

	hwrng_unregister(&virtio_hwrng);

	vdev->config->del_vqs(vdev);

	vq = NULL;

}



static int virtrng_probe(struct virtio_device *vdev)