This is a note to let you know that I've just added the patch titled
caif_virtio: fix race between virtio_device_ready() and ndo_open()
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
caif_virtio-fix-race-between-virtio_device_ready-and-ndo_open.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 11a37eb66812ce6a06b79223ad530eb0e1d7294d Mon Sep 17 00:00:00 2001
From: Jason Wang <jasowang@xxxxxxxxxx>
Date: Mon, 20 Jun 2022 13:11:14 +0800
Subject: caif_virtio: fix race between virtio_device_ready() and ndo_open()
From: Jason Wang <jasowang@xxxxxxxxxx>
commit 11a37eb66812ce6a06b79223ad530eb0e1d7294d upstream.
We currently depend on probe() calling virtio_device_ready() -
which happens 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 (e.g. TX) 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: 0d2e1a2926b18 ("caif_virtio: Introduce caif over virtio")
Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
Message-Id: <20220620051115.3142-3-jasowang@xxxxxxxxxx>
Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/caif/caif_virtio.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
--- a/drivers/net/caif/caif_virtio.c
+++ b/drivers/net/caif/caif_virtio.c
@@ -727,13 +727,21 @@ static int cfv_probe(struct virtio_devic
/* Carrier is off until netdevice is opened */
netif_carrier_off(netdev);
+ /* serialize netdev register + virtio_device_ready() with ndo_open() */
+ rtnl_lock();
+
/* register Netdev */
- err = register_netdev(netdev);
+ err = register_netdevice(netdev);
if (err) {
+ rtnl_unlock();
dev_err(&vdev->dev, "Unable to register netdev (%d)\n", err);
goto err;
}
+ virtio_device_ready(vdev);
+
+ rtnl_unlock();
+
debugfs_init(cfv);
return 0;
Patches currently in stable-queue which might be from jasowang@xxxxxxxxxx are
queue-4.9/caif_virtio-fix-race-between-virtio_device_ready-and-ndo_open.patch
