netdev - Re: [PATCH net 1/4 v2] ipvlan: fix addr hash list corruption

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Message-ID: <55159524.8010104@cogentembedded.com>
Date:	Fri, 27 Mar 2015 20:36:36 +0300
From:	Sergei Shtylyov <sergei.shtylyov@...entembedded.com>
To:	Jiri Benc <jbenc@...hat.com>, netdev@...r.kernel.org
CC:	Mahesh Bandewar <maheshb@...gle.com>,
	Dan Williams <dcbw@...hat.com>
Subject: Re: [PATCH net 1/4 v2] ipvlan: fix addr hash list corruption

Hello.

On 03/27/2015 08:30 PM, Jiri Benc wrote:

> When ipvlan interface with IP addresses attached is brought down and then
> deleted, the assigned addresses are deleted twice from the address hash
> list, first on the interface down and second on the link deletion.
> Similarly, when an address is added while the interface is down, it is added
> second time once the interface is brought up.

> When the interface is down, the addresses should be kept off the hash list
> for performance reasons. Ensure this is true, which also fixes the double add
> problem. To fix the double free, check whether the address is hashed before
> removing it.

> Reported-by: Dan Williams <dcbw@...hat.com>
> Signed-off-by: Jiri Benc <jbenc@...hat.com>
> ---

> Changes since v1: check hlist_unhashed on deletion instead of depending on
> netif_running

[...]

> diff --git a/drivers/net/ipvlan/ipvlan_main.c b/drivers/net/ipvlan/ipvlan_main.c
> index 4f4099d5603d..dbaf67c722a0 100644
> --- a/drivers/net/ipvlan/ipvlan_main.c
> +++ b/drivers/net/ipvlan/ipvlan_main.c
> @@ -622,7 +622,10 @@ static int ipvlan_add_addr6(struct ipvl_dev *ipvlan, struct in6_addr *ip6_addr)
>   	addr->atype = IPVL_IPV6;
>   	list_add_tail_rcu(&addr->anode, &ipvlan->addrs);
>   	ipvlan->ipv6cnt++;
> -	ipvlan_ht_addr_add(ipvlan, addr);
> +	/* If the interface is not up, the address will be added to the hash
> +	 * list by ipvlan_open. */

    The preferred multi-line comment style in the networking code is:

/* Like
  * this.
  */

[...]
> @@ -690,7 +693,10 @@ static int ipvlan_add_addr4(struct ipvl_dev *ipvlan, struct in_addr *ip4_addr)
>   	addr->atype = IPVL_IPV4;
>   	list_add_tail_rcu(&addr->anode, &ipvlan->addrs);
>   	ipvlan->ipv4cnt++;
> -	ipvlan_ht_addr_add(ipvlan, addr);
> +	/* If the interface is not up, the address will be added to the hash
> +	 * list by ipvlan_open. */

    Likewise.

[...]

WBR, Sergei

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