The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 50c0ada627f56c92f5953a8bf9158b045ad026a1 Mon Sep 17 00:00:00 2001
From: Jason Wang <jasowang@xxxxxxxxxx>
Date: Fri, 17 Jun 2022 15:29:49 +0800
Subject: [PATCH] virtio-net: fix race between ndo_open() and
virtio_device_ready()
We currently call virtio_device_ready() after netdev
registration. Since ndo_open() can be called immediately
after register_netdev, this means there exists a race between
ndo_open() and virtio_device_ready(): the driver may start to use the
device before DRIVER_OK which violates the spec.
Fix this by switching to use register_netdevice() and protect the
virtio_device_ready() with rtnl_lock() to make sure ndo_open() can
only be called after virtio_device_ready().
Fixes: 4baf1e33d0842 ("virtio_net: enable VQs early")
Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
Message-Id: <20220617072949.30734-1-jasowang@xxxxxxxxxx>
Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index db05b5e930be..8a5810bcb839 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -3655,14 +3655,20 @@ static int virtnet_probe(struct virtio_device *vdev)
if (vi->has_rss || vi->has_rss_hash_report)
virtnet_init_default_rss(vi);
- err = register_netdev(dev);
+ /* serialize netdev register + virtio_device_ready() with ndo_open() */
+ rtnl_lock();
+
+ err = register_netdevice(dev);
if (err) {
pr_debug("virtio_net: registering device failed\n");
+ rtnl_unlock();
goto free_failover;
}
virtio_device_ready(vdev);
+ rtnl_unlock();
+
err = virtnet_cpu_notif_add(vi);
if (err) {
pr_debug("virtio_net: registering cpu notifier failed\n");
