netdev - Re: [PATCH net-next] net: ipv6: ignore null

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Message-ID: <95b123db-a760-b73a-a858-9be0516799fc@cumulusnetworks.com>
Date:   Tue, 24 Jan 2017 18:35:02 -0700
From:   David Ahern <dsa@...ulusnetworks.com>
To:     David Miller <davem@...emloft.net>
Cc:     netdev@...r.kernel.org, xiaolong.ye@...el.com
Subject: Re: [PATCH net-next] net: ipv6: ignore null_entry on route dumps

On 1/23/17 9:51 AM, David Ahern wrote:
> On 1/22/17 9:58 PM, David Miller wrote:
>> David, please slow down.
>>
>> How is the NULL entry getting selected to be dumped and passed
>> down here in the first place?
> The null_entry might be a 'marker' but is integral to the ipv6 fib.

As I mentioned in my last response the null_entry is tb6_root.leaf for all tables making it part of the table. Since the dump walks the table and sends each route to rt6_dump_route, the dump includes the null_entry.

ip6_null_entry->rt6i_idev is NULL because ip6_route_net_init is run before addrconf_init has initialized the loopback device.

Given that, it seems like a check is needed somewhere ...  be it 'rt == net->ipv6.ip6_null_entry' in rt6_dump_route or fib6_dump_node, or a check for rt6i_idev NULL in rt6_fill_node.

You marked the last patch as changes needed meaning another needs to be sent.

Suggestion?