IPv6: 2.4.2/3 autoconfiguration sometimes didn't work

[Peter Bieringer <pb@xxxxxxxxxxxx>]

Hi,

testing the new RedHat 7.1 distribution I ran into a strange problem 
regarding the work of autoconfiguration:

Scenario:
worker (RH7.1) [..:9205] --- LAN --- gate (2.2.19pre16, running radvd) 
[..:b4f5]

Tested kernels on worker:
2.4.2-2 (RH 7.1)
2.4.3 vanilla, fresh compiled

Kernel on gate:
2.2.19pre16 vanilla
Radvd-Version: 0.6.2pl1


After booting, all is ok, IPv6 is autoconfigured.

If I run "/etc/rc.d/init.d/network restart", autoconfiguration doesn't work 
anymore.

Packets on the LAN:

09:06:49.887982 :: > ff02::1:ff90:9205: icmp6: neighbor sol: who has 
fe80::2e0:18ff:fe90:9205
09:06:50.728393 fe80::250:bfff:fe06:b4f5 > ff02::1: icmp6: router advertisement
09:06:53.888279 fe80::2e0:18ff:fe90:9205 > ff02::2: icmp6: router solicitation
09:06:53.898402 fe80::250:bfff:fe06:b4f5 > ff02::1: icmp6: router advertisement
09:07:03.788411 fe80::250:bfff:fe06:b4f5 > ff02::1: icmp6: router advertisement
09:07:12.448429 fe80::250:bfff:fe06:b4f5 > ff02::1: icmp6: router advertisement

Nothing happens on worker anymore.

If I shut down the interface by hand "ifconfig eth0 down", wait some 
seconds and put it up again "ifconfig eth0 up" most of the time 
autoconfiguration works again:

09:07:13.929671 :: > ff02::1:ff90:9205: icmp6: neighbor sol: who has 
fe80::2e0:18ff:fe90:9205
09:07:17.288425 fe80::250:bfff:fe06:b4f5 > ff02::1: icmp6: router advertisement
09:07:17.929976 fe80::2e0:18ff:fe90:9205 > ff02::2: icmp6: router solicitation
09:07:18.248493 fe80::250:bfff:fe06:b4f5 > ff02::1:ff90:9205: icmp6: 
neighbor sol: who has fe80::2e0:18ff:fe90:9205
09:07:18.248677 fe80::2e0:18ff:fe90:9205 > fe80::250:bfff:fe06:b4f5: icmp6: 
neighbor adv: tgt is fe80::2e0:18ff:fe90:9205
09:07:18.248778 fe80::250:bfff:fe06:b4f5 > fe80::2e0:18ff:fe90:9205: icmp6: 
router advertisement
09:07:18.749995 :: > ff02::1:ff90:9205: icmp6: neighbor sol: who has 
2002:d950:249d:f101:2e0:18ff:fe90:92
05
09:07:26.698501 fe80::250:bfff:fe06:b4f5 > ff02::1: icmp6: router advertisement


Very strange! As far as I remember, with USAGI patches on 2.4 kernel such 
problem never occurs.

Can someone reproduce this?

Is there a timer somewhere which is not cleared on interface shutdown or 
something else?

TIA,
        Peter