netdev - Re: [net] net: fix double free issue of skbuff

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Date:	Mon, 29 Feb 2016 15:58:21 +0300
From:	Sergei Shtylyov <sergei.shtylyov@...entembedded.com>
To:	Zhang Shengju <zhangshengju@...s.chinamobile.com>,
	davem@...emloft.net, netdev@...r.kernel.org
Subject: Re: [net] net: fix double free issue of skbuff

Hello.

On 2/29/2016 3:22 PM, Zhang Shengju wrote:

> If skb_reorder_vlan_header() failed, skb is freed and NULL is returned.
> Then at skb_vlan_untag(), it will free skbuff again which cause double
> free.
>
> This patch removes kfree_skb() call in function skb_reorder_vlan_header().
>
> Signed-off-by: Zhang Shengju <zhangshengju@...s.chinamobile.com>
> ---
>   net/core/skbuff.c | 1 -
>   1 file changed, 1 deletion(-)
>
> diff --git a/net/core/skbuff.c b/net/core/skbuff.c
> index 488566b..1312d4b 100644
> --- a/net/core/skbuff.c
> +++ b/net/core/skbuff.c
> @@ -4350,7 +4350,6 @@ EXPORT_SYMBOL_GPL(skb_gso_transport_seglen);
>   static struct sk_buff *skb_reorder_vlan_header(struct sk_buff *skb)
>   {
>   	if (skb_cow(skb, skb_headroom(skb)) < 0) {
> -		kfree_skb(skb);
>   		return NULL;
>   	}

    You now need to remove {}.

MBR, Sergei