[PATCH] virtio_console: fix misc probe bugs

From: Michael S. Tsirkin
Date: Mon Sep 16 2024 - 14:33:17 EST


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@xxxxxxxxxx>
---
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