On 7/25/17 1:32 AM, Hangbin Liu wrote: > On Mon, Jul 24, 2017 at 09:28:07PM -0600, David Ahern wrote: >> On 7/24/17 6:08 PM, Hangbin Liu wrote: >>> That's why I think we should remove both rt->dst.error and ip6_null_entry >>> check in inet6_rtm_getroute(). And even further, remove the ip6_null_entry >>> check in rt6_dump_route(). >> >> git blame net/ipv6/route.c >> >> find the commits and review. > > Hi David, > > Sorry, would you like to give me more hints? > > I saw your commit 1f17e2f2c8a8 ("net: ipv6: ignore null_entry on route > dumps"). But I think this issue has been fixed by > > 2f460933f58e ("ipv6: initialize route null entry in addrconf_init()") and > 242d3a49a2a1 ("ipv6: reorder ip6_route_dev_notifier after ipv6_dev_notf") > > I use a reproducer which add unreachable route in netns with lo down. And I > could not trigger Panic in the fixed kernel. That's why I think we could > remove ip6_null_entry check in rt6_dump_route().
Understood. Cong's patch to fix the intialization order (lo device before route init) makes sure the idev is not null. That said, the null_entry route is internal ipv6 logic and is not a route entry to be returned to userspace.