On 2019/1/17 下午7:20, Toshiaki Makita wrote:
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.toshi...@lab.ntt.co.jp>
---
  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;


Acked-by: Jason Wang <jasow...@redhat.com>


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