[PATCH net-next v7 4/4] virtio-net: synchronize probe with ndo_set_features

From: Jason Wang
Date: Wed Aug 14 2024 - 01:24:08 EST


We calculate guest offloads during probe without the protection of
rtnl_lock. This lead to race between probe and ndo_set_features. Fix
this by moving the calculation under the rtnl_lock.

Fixes: 3f93522ffab2 ("virtio-net: switch off offloads on demand if possible on XDP set")
Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
---
drivers/net/virtio_net.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 55b712a71e63..6c79fc43fa31 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -6606,6 +6606,11 @@ static int virtnet_probe(struct virtio_device *vdev)
netif_carrier_on(dev);
}

+ for (i = 0; i < ARRAY_SIZE(guest_offloads); i++)
+ if (virtio_has_feature(vi->vdev, guest_offloads[i]))
+ set_bit(guest_offloads[i], &vi->guest_offloads);
+ vi->guest_offloads_capable = vi->guest_offloads;
+
rtnl_unlock();

err = virtnet_cpu_notif_add(vi);
@@ -6614,11 +6619,6 @@ static int virtnet_probe(struct virtio_device *vdev)
goto free_unregister_netdev;
}

- for (i = 0; i < ARRAY_SIZE(guest_offloads); i++)
- if (virtio_has_feature(vi->vdev, guest_offloads[i]))
- set_bit(guest_offloads[i], &vi->guest_offloads);
- vi->guest_offloads_capable = vi->guest_offloads;
-
pr_debug("virtnet: registered device %s with %d RX and TX vq's\n",
dev->name, max_queue_pairs);

--
2.31.1