Subject: Re: [PATCH] ipv6: clear RTF_EXPIRES when call ip6_rt_copy

From: Gao feng <[email-masked]>
Date: Tue, 17 Dec 2013 13:57:55 +0800

On 12/17/2013 11:32 AM, RongQing Li wrote:
> If the ort->rt6i_flags is RTF_EXPIRES|RTF_ADDRCONF, then rt6_set_from will not
> be called, and new created rt will have RTF_EXPIRES, but dst.expires is 0, and
> dst.from is NULL

Ok, but I think you need to add more detail/test purpose of the test case v6LC.4.1.4
{ Reduce PMTU On-link }. just the number of test case is not good for people to know
what's the real problem.

> 
> -Roy
> 
> 2013/12/17 Gao feng <[email-masked]>:
>> On 12/16/2013 04:31 PM, [email-masked] wrote:
>>> From: Li RongQing <[email-masked]>
>>>
>>> The commit ecd9883724b [ipv6: fix race condition regarding dst->expires and
>>> dst->from.] removed rt6_clean_expires in ip6_rt_copy, which causes the TAHI
>>> test case v6LC.4.1.4 { Reduce PMTU On-link } failed, since the newly generated
>>> rt maybe always expired {with RTF_EXPIRES flag, dst.expires is 0, and dst.from
>>> is NULL}.
>>>
>>> Fix it by clearing RTF_EXPIRES as before 1716a96101[ipv6: fix problem with
>>> expired dst cache]
>>>
>>> Signed-off-by: Li RongQing <[email-masked]>
>>> ---
>>>  net/ipv6/route.c |    2 +-
>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/net/ipv6/route.c b/net/ipv6/route.c
>>> index a1a5752..e3d7f21 100644
>>> --- a/net/ipv6/route.c
>>> +++ b/net/ipv6/route.c
>>> @@ -1908,7 +1908,7 @@ static struct rt6_info *ip6_rt_copy(struct rt6_info *ort,
>>>                       rt->rt6i_gateway = ort->rt6i_gateway;
>>>               else
>>>                       rt->rt6i_gateway = *dest;
>>> -             rt->rt6i_flags = ort->rt6i_flags;
>>> +             rt->rt6i_flags = ort->rt6i_flags & ~RTF_EXPIRES;
>>>               if ((ort->rt6i_flags & (RTF_DEFAULT | RTF_ADDRCONF)) ==
>>>                   (RTF_DEFAULT | RTF_ADDRCONF))
>>>                       rt6_set_from(rt, ort);
>>>
>>
>> I don't understand, rt6_set_from already clears the RTF_EXPIRES from rt->rt6i_flags.
>>
>