netdev - Re: [PATCH net] adding missing rcu_read_unlock in ipxip6

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Message-ID: <2F365C63-C7DF-4F48-9656-22B4BD7F3F32@fb.com>
Date:   Thu, 7 Dec 2017 00:28:32 +0000
From:   Nikita Shirokov <tehnerd@...com>
To:     David Miller <davem@...emloft.net>
CC:     "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "ast@...nel.org" <ast@...nel.org>,
        "vnuorval@....hut.fi" <vnuorval@....hut.fi>
Subject: Re: [PATCH net] adding missing rcu_read_unlock in ipxip6_rcv



On 12/6/17, 12:50 PM, "David Miller" <davem@...emloft.net> wrote:

    From: "Nikita V. Shirokov" <tehnerd@...com>
    Date: Wed,  6 Dec 2017 10:19:33 -0800
    
    > commit 8d79266bc48c ("ip6_tunnel: add collect_md mode to IPv6 tunnels")
    > introduced new exit point in  ipxip6_rcv. however rcu_read_unlock is
    > missing there. this diff is fixing this
    > 
    > Signed-off-by: Nikita V. Shirokov <tehnerd@...com>
     ...
    > @@ -903,8 +903,10 @@ static int ipxip6_rcv(struct sk_buff *skb, u8 ipproto,
    >  			goto drop;
    >  		if (t->parms.collect_md) {
    >  			tun_dst = ipv6_tun_rx_dst(skb, 0, 0, 0);
    > -			if (!tun_dst)
    > +			if (!tun_dst) {
    > +				rcu_read_unlock();
    >  				return 0;
    > +			}
    >  		}
    >  		ret = __ip6_tnl_rcv(t, skb, tpi, tun_dst, dscp_ecn_decapsulate,
    >  				    log_ecn_error);
    
    Shouldn't it branch to 'drop' otherwise we leak the skb?
    

Fair point, will rework.

--
Nikita