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.

Fixes: 17634ba25544 ("virtio: console: Add a new MULTIPORT feature, support for generic ports")
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 drivers/char/virtio_console.c | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index de7d720d99fa..bcb05fc44c99 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -2007,25 +2007,27 @@ 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,
-- 
MST

On Mon, 2024-09-16 at 14:32 -0400, Michael S. Tsirkin wrote:
> 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.
> 
> Fixes: 17634ba25544 ("virtio: console: Add a new MULTIPORT feature,
> support for generic ports")
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Reviewed-by: Amit Shah <amit@kernel.org>

On Mon, Sep 16, 2024 at 02:32:56PM -0400, Michael S. Tsirkin wrote:
> 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.
> 
> Fixes: 17634ba25544 ("virtio: console: Add a new MULTIPORT feature, support for generic ports")
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
>  drivers/char/virtio_console.c | 18 ++++++++++--------
>  1 file changed, 10 insertions(+), 8 deletions(-)

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