virtio-net: fix refill races during restore

During restoring, try_fill_recv() was called with neither napi lock nor napi
disabled. This can lead two try_fill_recv() was called in the same time. Fix
this by refilling before trying to enable napi.

Fixes 0741bcb5584f9e2390ae6261573c4de8314999f2
(virtio: net: Add freeze, restore handlers to support S4).

Cc: Amit Shah <amit.shah@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 6 insertions, 5 deletions

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index d208f8604981..5d776447d9c3 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -1797,16 +1797,17 @@ static int virtnet_restore(struct virtio_device *vdev)
         if (err)
                 return err;
 
-        if (netif_running(vi->dev))
+        if (netif_running(vi->dev)) {
+                for (i = 0; i < vi->curr_queue_pairs; i++)
+                        if (!try_fill_recv(&vi->rq[i], GFP_KERNEL))
+                                schedule_delayed_work(&vi->refill, 0);
+
                 for (i = 0; i < vi->max_queue_pairs; i++)
                         virtnet_napi_enable(&vi->rq[i]);
+        }
 
         netif_device_attach(vi->dev);
 
-        for (i = 0; i < vi->curr_queue_pairs; i++)
-                if (!try_fill_recv(&vi->rq[i], GFP_KERNEL))
-                        schedule_delayed_work(&vi->refill, 0);
-
         mutex_lock(&vi->config_lock);
         vi->config_enable = true;
         mutex_unlock(&vi->config_lock);