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

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Date:	Mon, 29 Feb 2016 22:10:47 +0800
From:	张胜举 <zhangshengju@...s.chinamobile.com>
To:	"'Sergei Shtylyov'" <sergei.shtylyov@...entembedded.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

Thanks Sergei, I will add this in v2. 

BRs,
Shengju