From: "Michael S. Tsirkin" <mst@redhat•com>
To: Eric Dumazet <eric.dumazet@gmail•com>
Cc: David Miller <davem@davemloft•net>,
netdev <netdev@vger•kernel.org>, Jason Wang <jasowang@redhat•com>
Subject: Re: [PATCH net] virtio-net: add a missing synchronize_net()
Date: Wed, 16 Nov 2016 15:55:46 +0200 [thread overview]
Message-ID: <20161116155537-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <1479277452.8455.156.camel@edumazet-glaptop3.roam.corp.google.com>
On Tue, Nov 15, 2016 at 10:24:12PM -0800, Eric Dumazet wrote:
> From: Eric Dumazet <edumazet@google•com>
>
> 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>
> ---
> drivers/net/virtio_net.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index fd8b1e62301f..7276d5a95bd0 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -1497,6 +1497,11 @@ static void virtnet_free_queues(struct virtnet_info *vi)
> 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);
> }
>
next prev parent reply other threads:[~2016-11-16 13:55 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-16 6:24 [PATCH net] virtio-net: add a missing synchronize_net() Eric Dumazet
2016-11-16 13:55 ` Michael S. Tsirkin [this message]
2016-11-16 20:12 ` David Miller
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