| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.8 02/45] virtio-net: add a missing synchronize_net() | Date | Fri, 9 Dec 2016 17:20:31 +0100 |
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4.8-stable review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet <edumazet@google.com>
[ Upstream commit 963abe5c8a0273a1cf5913556da1b1189de0e57a ]
It seems many drivers do not respect napi_hash_del() contract.
When napi_hash_del() is used before netif_napi_del(), an RCU grace period is needed before freeing NAPI object.
Fixes: 91815639d880 ("virtio-net: rx busy polling support") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Michael S. Tsirkin <mst@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 | 5 +++++ 1 file changed, 5 insertions(+)
--- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -1468,6 +1468,11 @@ static void virtnet_free_queues(struct v netif_napi_del(&vi->rq[i].napi); } + /* We called napi_hash_del() before netif_napi_del(), + * we need to respect an RCU grace period before freeing vi->rq + */ + synchronize_net(); + kfree(vi->rq); kfree(vi->sq); }
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