> On Mon, 2016-02-01 at 11:37 -0800, Eric Dumazet wrote:
>
>> I would rather try :
>>
>> diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
>> index 38eeddedfc21..d6b7ab07f914 100644
>> --- a/net/ipv6/addrconf.c
>> +++ b/net/ipv6/addrconf.c
>> @@ -3538,6 +3538,7 @@ static void addrconf_dad_begin(struct inet6_ifaddr
>> *ifp)
>> {
>> struct inet6_dev *idev = ifp->idev;
>> struct net_device *dev = idev->dev;
>> + bool notify = false;
>>
>> addrconf_join_solict(dev, &ifp->addr);
>>
>> @@ -3583,7 +3584,8 @@ static void addrconf_dad_begin(struct inet6_ifaddr
>> *ifp)
>> /* Because optimistic nodes can use this address,
>> * notify listeners. If DAD fails, RTM_DELADDR is sent.
>> */
>> - ipv6_ifa_notify(RTM_NEWADDR, ifp);
>> + notify = true;
>> + in6_ifa_hold(ifp);
>
> Actually the in6_ifa_hold() is not needed.
>
>> }
>> }
>>
>> @@ -3591,6 +3593,10 @@ static void addrconf_dad_begin(struct
>> inet6_ifaddr *ifp)
>> out:
>> spin_unlock(&ifp->lock);
>> read_unlock_bh(&idev->lock);
>> + if (notify) {
>> + ipv6_ifa_notify(RTM_NEWADDR, ifp);
>> + in6_ifa_put(ifp);
>
> And in6_ifa_put() not needed once in6_ifa_hold() is removed.
>
>> + }
>> }
>>
>> static void addrconf_dad_start(struct inet6_ifaddr *ifp)
>>
>>
Thanks Eric. I tested the scenario with your suggestion and I don't see a
RCU stall now. I will send out v2 of this patch.
