linux-kernel - Re: [PATCH net] virtio-net: fix pages leaking when building skb in big mode

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Date:   Sat, 18 Sep 2021 09:56:13 +0800
From:   Xuan Zhuo <xuanzhuo@...ux.alibaba.com>
To:     Jason Wang <jasowang@...hat.com>
Cc:     mst@...hat.com, jasowang@...hat.com,
        virtualization@...ts.linux-foundation.org, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH net] virtio-net: fix pages leaking when building skb in
 big mode

On Fri, 17 Sep 2021 16:34:06 +0800, Jason Wang <jasowang@...hat.com> wrote:
> We try to use build_skb() if we had sufficient tailroom. But we forget
> to release the unused pages chained via private in big mode which will
> leak pages. Fixing this by release the pages after building the skb in
> big mode.
>
> Cc: Xuan Zhuo <xuanzhuo@...ux.alibaba.com>
> Fixes: fb32856b16ad ("virtio-net: page_to_skb() use build_skb when there's sufficient tailroom")
> Signed-off-by: Jason Wang <jasowang@...hat.com>

LGTM

Reviewed-by: Xuan Zhuo <xuanzhuo@...ux.alibaba.com>

Thanks.


> ---
>  drivers/net/virtio_net.c | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 271d38c1d9f8..79bd2585ec6b 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -423,6 +423,10 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi,
>
>  		skb_reserve(skb, p - buf);
>  		skb_put(skb, len);
> +
> +		page = (struct page *)page->private;
> +		if (page)
> +			give_pages(rq, page);
>  		goto ok;
>  	}
>
> --
> 2.25.1
>