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

From: Alexander Duyck <[email-masked]>
Date: Thu, 25 Apr 2013 13:36:06 -0700

On 04/25/2013 01:25 PM, David Miller wrote:
> 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
>>>
>>> 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.
> I wonder if we are seeing two ways tools are making these calls, some are
> passing rtgenmsg and some are passing ifinfomsg.  The latter, I am mostly
> convinced, is what we must see here from properly written applications.
>
> That would be really unfortunate, but seeing a nlmsg_attrlen() of -12 would
> seem to confirm that a rtgenmsg was used.
>
> I guess you're using iproute2?

Yes.  All I am doing is ip link show and previously this would display
VF info as well as PF.  Now the VF info is not there.

>>From what I can tell the problem call is rtnl_wilddump_req_filter since
it is only passing a rtgenmsg and asking us to dump the link with the
RTEXT_FILTER_VF filter mask.

Thanks,

Alex