[BISECTED] [4.17.0-rc6] IPv6 link-local address not getting added

[BISECTED] [4.17.0-rc6] IPv6 link-local address not getting added

[Sowmini Varadhan]

Hi David,

An IPv6 regression has been introduced in 4.17.0-rc6 by
  8308f3f net/ipv6: Add support for specifying metric of connected routes

The regression is that some interfaces on my test machine come
up with link-local addrs but the fe80 prefix is missing.
After this bug, I cannot send any packets to anyone onlink 
(including my routers). 

Here are the symptoms:

When everything is fine, "ip -6 route|grep eno" shows

2606:b400:400:18c8::/64 dev eno1 proto ra metric 100  pref medium
fe80::5:73ff:fea0:52d dev eno1 proto static metric 100  pref medium
fe80::/64 dev eno1 proto kernel metric 256  pref medium
fe80::/64 dev eno3 proto kernel metric 256  pref medium
fe80::/64 dev eno4 proto kernel metric 256  pref medium
default via fe80::5:73ff:fea0:52d dev eno1 proto static metric 100  pref medium

But after 8308f3f, I only find

# ip -6 route|grep eno
2606:b400:400:18c8::/64 dev eno1 proto ra metric 100  pref medium
fe80::5:73ff:fea0:52d dev eno1 proto static metric 100  pref medium
fe80::/64 dev eno1 proto kernel metric 256  pref medium
default via fe80::5:73ff:fea0:52d dev eno1 proto static metric 100  pref medium

(note that eno2 is not enabled in my config, so its absence is expected)

Please have a look, thanks.
--Sowmini

Re: [BISECTED] [4.17.0-rc6] IPv6 link-local address not getting added

[David Ahern]

On 6/27/18 6:35 PM, Sowmini Varadhan wrote:
> 
> Hi David,
> 
> An IPv6 regression has been introduced in 4.17.0-rc6 by
>   8308f3f net/ipv6: Add support for specifying metric of connected routes
> 
> The regression is that some interfaces on my test machine come
> up with link-local addrs but the fe80 prefix is missing.
> After this bug, I cannot send any packets to anyone onlink 
> (including my routers). 
> 
> Here are the symptoms:
> 
> When everything is fine, "ip -6 route|grep eno" shows
> 
> 2606:b400:400:18c8::/64 dev eno1 proto ra metric 100  pref medium
> fe80::5:73ff:fea0:52d dev eno1 proto static metric 100  pref medium
> fe80::/64 dev eno1 proto kernel metric 256  pref medium
> fe80::/64 dev eno3 proto kernel metric 256  pref medium
> fe80::/64 dev eno4 proto kernel metric 256  pref medium
> default via fe80::5:73ff:fea0:52d dev eno1 proto static metric 100  pref medium
> 
> But after 8308f3f, I only find
> 
> # ip -6 route|grep eno
> 2606:b400:400:18c8::/64 dev eno1 proto ra metric 100  pref medium
> fe80::5:73ff:fea0:52d dev eno1 proto static metric 100  pref medium
> fe80::/64 dev eno1 proto kernel metric 256  pref medium
> default via fe80::5:73ff:fea0:52d dev eno1 proto static metric 100  pref medium
> 
> (note that eno2 is not enabled in my config, so its absence is expected)
> 
> Please have a look, thanks.
> --Sowmini
> 

interesting. I am not seeing that. Using your static LL routes:

# ip -6 ro ls
::1 dev lo proto kernel metric 256 pref medium
2001:db8:2::/120 dev eth2 proto kernel metric 256 pref medium
fe80::5:73ff:fea0:52d dev eth4 metric 100 pref medium
fe80::/64 dev eth4 proto kernel metric 256 pref medium
fe80::/64 dev eth5 proto kernel metric 256 pref medium
fe80::/64 dev eth6 proto kernel metric 256 pref medium
fe80::/64 dev eth7 proto kernel metric 256 pref medium
fe80::/64 dev eth8 proto kernel metric 256 pref medium
fe80::/64 dev eth2 proto kernel metric 256 pref medium
default via fe80::5:73ff:fea0:52d dev eth4 metric 100 pref medium

can you send me the network config files (off list is fine)? What's the
interface manager and any routing daemon in use?