[PATCH 5.17 288/298] virtio-rng: make device ready before making request

[Greg Kroah-Hartman]

From: Jason Wang <jasowang@xxxxxxxxxx>

commit 228432551bd8783211e494ab35f42a4344580502 upstream.

Current virtio-rng does a entropy request before DRIVER_OK, this
violates the spec:

virtio spec requires that all drivers set DRIVER_OK
before using devices.

Further, kernel will ignore the interrupt after commit
8b4ec69d7e09 ("virtio: harden vring IRQ").

Fixing this by making device ready before the request.

Cc: stable@xxxxxxxxxxxxxxx
Fixes: 8b4ec69d7e09 ("virtio: harden vring IRQ")
Fixes: f7f510ec1957 ("virtio: An entropy device, as suggested by hpa.")
Reported-and-tested-by: syzbot+5b59d6d459306a556f54@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
Message-Id: <20220608061422.38437-1-jasowang@xxxxxxxxxx>
Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
Reviewed-by: Laurent Vivier <lvivier@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/char/hw_random/virtio-rng.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/char/hw_random/virtio-rng.c
+++ b/drivers/char/hw_random/virtio-rng.c
@@ -159,6 +159,8 @@ static int probe_common(struct virtio_de
 		goto err_find;
 	}
 
+	virtio_device_ready(vdev);
+
 	/* we always have a pending entropy request */
 	request_entropy(vi);