Subject: Re: [PATCH] ipv6: reallocate addrconf router for ipv6 address when lo device up

From: Gao feng <[email-masked]>
Date: Fri, 24 Jan 2014 09:14:04 +0800

On 01/24/2014 05:03 AM, Hannes Frederic Sowa wrote:
> On Thu, Jan 23, 2014 at 02:57:57PM +0800, Gao feng wrote:
>> commit 25fb6ca4ed9cad72f14f61629b68dc03c0d9713f
>> "net IPv6 : Fix broken IPv6 routing table after loopback down-up"
>> allocates addrconf router for ipv6 address when lo device up.
>> but commit a881ae1f625c599b460cc8f8a7fcb1c438f699ad
>> "ipv6:don't call addrconf_dst_alloc again when enable lo" breaks
>> this behavior.
>>
>> Since the addrconf router is moved to the garbage list when
>> lo device down, we should delete this router and rellocate
>> a new one for ipv6 address when lo device up.
>>
>> This patch solves bug 67951 on bugzilla
>> https://bugzilla.kernel.org/show_bug.cgi?id=67951
>>
>> CC: Sabrina Dubroca <[email-masked]>
>> CC: Hannes Frederic Sowa <[email-masked]>
>> Reported-by: Weilong Chen <[email-masked]>
>> Signed-off-by: Weilong Chen <[email-masked]>
>> Signed-off-by: Gao feng <[email-masked]>
>> ---
>>  net/ipv6/addrconf.c | 13 +++++++++++--
>>  1 file changed, 11 insertions(+), 2 deletions(-)
>>
>> diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
>> index 4b6b720..6eecd9d 100644
>> --- a/net/ipv6/addrconf.c
>> +++ b/net/ipv6/addrconf.c
>> @@ -2611,8 +2611,17 @@ static void init_loopback(struct net_device *dev)
>>  			if (sp_ifa->flags & (IFA_F_DADFAILED | IFA_F_TENTATIVE))
>>  				continue;
>>  
>> -			if (sp_ifa->rt)
>> -				continue;
>> +			if (sp_ifa->rt) {
>> +				/* This dst has been added to garbage list when
>> +				 * lo device down, delete this obsolete dst and
>> +				 * reallocate a new router for ifa.
>> +				 */
>> +				if (sp_ifa->rt->dst.obsolete > 0) {
>> +					ip6_del_rt(sp_ifa->rt);
> 
> We should not delete dst.obsolete > 0 routes. I think a ip6_put_rt is just
> fine here, no?
> 

Yes, definitely. this route has already been delete from route tree in fib6_clean_all.
no need delete it again.

Thanks, I will post v2 patch.