virtio_console: fix misc probe bugs

BugLink: https://bugs.launchpad.net/bugs/2097301

[ Upstream commit b9efbe2 ]

This fixes the following issue discovered by code review:

after vqs have been created, a buggy device can send an interrupt.

A control vq callback will then try to schedule control_work which has
not been initialized yet. Similarly for config interrupt.  Further, in
and out vq callbacks invoke find_port_by_vq which attempts to take
ports_lock which also has not been initialized.

To fix, init all locks and work before creating vqs.

Message-ID: <ad982e975a6160ad110c623c016041311ca15b4f.1726511547.git.mst@redhat.com>
Fixes: 17634ba ("virtio: console: Add a new MULTIPORT feature, support for generic ports")
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Manuel Diewald <manuel.diewald@canonical.com>
Signed-off-by: Koichiro Den <koichiro.den@canonical.com>

Author: mstsirkin

drivers/char/virtio_console.c

@@ -2016,25 +2016,27 @@ static int virtcons_probe(struct virtio_device *vdev)
 		multiport = true;
 	}
 
-	err = init_vqs(portdev);
-	if (err < 0) {
-		dev_err(&vdev->dev, "Error %d initializing vqs\n", err);
-		goto free_chrdev;
-	}
-
 	spin_lock_init(&portdev->ports_lock);
 	INIT_LIST_HEAD(&portdev->ports);
 	INIT_LIST_HEAD(&portdev->list);
 
-	virtio_device_ready(portdev->vdev);
-
 	INIT_WORK(&portdev->config_work, &config_work_handler);
 	INIT_WORK(&portdev->control_work, &control_work_handler);
 
 	if (multiport) {
 		spin_lock_init(&portdev->c_ivq_lock);
 		spin_lock_init(&portdev->c_ovq_lock);
+	}
 
+	err = init_vqs(portdev);
+	if (err < 0) {
+		dev_err(&vdev->dev, "Error %d initializing vqs\n", err);
+		goto free_chrdev;
+	}
+
+	virtio_device_ready(portdev->vdev);
+
+	if (multiport) {
 		err = fill_queue(portdev->c_ivq, &portdev->c_ivq_lock);
 		if (err < 0) {
 			dev_err(&vdev->dev,