Commit 4e09ff536284 ("virtio-net: disable NAPI only when enabled during
XDP set") tried to fix inappropriate NAPI enabling/disabling when
!netif_running(), but was not complete.

On error path virtio_net could enable NAPI even when !netif_running().
This can cause enabling NAPI twice on virtnet_open(), which would
trigger BUG_ON() in napi_enable().

Fixes: 4941d472bf95b ("virtio-net: do not reset during XDP set")
Signed-off-by: Toshiaki Makita <redacted>
---
  drivers/net/virtio_net.c | 6 ++++--
  1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 0237250..a08da9e 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c

@@ -2430,8 +2430,10 @@ static int virtnet_xdp_set(struct net_device *dev, struct bpf_prog *prog,
  	return 0;
  
  err:
-	for (i = 0; i < vi->max_queue_pairs; i++)
-		virtnet_napi_enable(vi->rq[i].vq, &vi->rq[i].napi);
+	if (netif_running(dev)) {
+		for (i = 0; i < vi->max_queue_pairs; i++)
+			virtnet_napi_enable(vi->rq[i].vq, &vi->rq[i].napi);
+	}
  	if (prog)
  		bpf_prog_sub(prog, vi->max_queue_pairs - 1);
  	return err;