[PATCH 4.14 12/46] virtio_net: Dont enable NAPI when interface is down

Greg Kroah-Hartman
2019-02-04T10:44:34Z

From: Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp>

[ Upstream commit 8be4d9a492f88b96d4d3a06c6cbedbc40ca14c83 ]

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 <makita.toshiaki@lab.ntt.co.jp>
Acked-by: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/virtio_net.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -2034,8 +2034,10 @@ static int virtnet_xdp_set(struct net_de
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;