Subject: Re: getting VF link info seems to be broken in 3.9-rc8

From: Alexander Duyck <[email-masked]>
Date: Thu, 25 Apr 2013 13:20:24 -0700

On 04/25/2013 12:24 PM, David Miller wrote:
> From: Alexander Duyck <[email-masked]>
> Date: Thu, 25 Apr 2013 11:29:04 -0700
>
>> I did a bit of digging and it looks like the issue is that the
>> ext_filter_mask is not being found in the message received in
>> rtnl_dump_ifinfo.  I'm still trying to figure out why the kernel isn't
>> finding the flag when it was finding it previously, but I'm not much of
>> a netlink expert.
> I wonder if this has something to do with this commit:
>
> ====================
> From 88c5b5ce5cb57af6ca2a7cf4d5715fa320448ff9 Mon Sep 17 00:00:00 2001
> From: Michael Riesch <[email-masked]>
> Date: Mon, 8 Apr 2013 05:45:26 +0000
> Subject: [PATCH] rtnetlink: Call nlmsg_parse() with correct header length
>
> Signed-off-by: Michael Riesch <[email-masked]>
> Cc: "David S. Miller" <[email-masked]>
> Cc: Greg Kroah-Hartman <[email-masked]>
> Cc: Jiri Benc <[email-masked]>
> Cc: "Theodore Ts'o" <[email-masked]>
> Cc: [email-masked]
> Acked-by: Mark Rustad <[email-masked]>
> Signed-off-by: David S. Miller <[email-masked]>
> ---
>  net/core/rtnetlink.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
> index b65441d..23854b5 100644
> --- a/net/core/rtnetlink.c
> +++ b/net/core/rtnetlink.c
> @@ -1072,7 +1072,7 @@ static int rtnl_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb)
>  	rcu_read_lock();
>  	cb->seq = net->dev_base_seq;
>  
> -	if (nlmsg_parse(cb->nlh, sizeof(struct rtgenmsg), tb, IFLA_MAX,
> +	if (nlmsg_parse(cb->nlh, sizeof(struct ifinfomsg), tb, IFLA_MAX,
>  			ifla_policy) >= 0) {
>  
>  		if (tb[IFLA_EXT_MASK])
> @@ -1922,7 +1922,7 @@ static u16 rtnl_calcit(struct sk_buff *skb, struct nlmsghdr *nlh)
>  	u32 ext_filter_mask = 0;
>  	u16 min_ifinfo_dump_size = 0;
>  
> -	if (nlmsg_parse(nlh, sizeof(struct rtgenmsg), tb, IFLA_MAX,
> +	if (nlmsg_parse(nlh, sizeof(struct ifinfomsg), tb, IFLA_MAX,
>  			ifla_policy) >= 0) {
>  		if (tb[IFLA_EXT_MASK])
>  			ext_filter_mask = nla_get_u32(tb[IFLA_EXT_MASK]);

I thought that as well.  I tried reverting it and the issue is still there.

However, I do think this may be part of the issue since I added a printk
to dump nlmsg_attrlen before going into the nlmsg_parse and with
ifinfomsg the attrlen is -12, with rtgenmsg it is 0.

Thanks,

Alex