On Thu, Mar 07, 2024 at 10:12:54AM +0000, Simon Horman wrote: > Hi Linus, > > this appears to be a fix and as such I think it warrants a Fixes tag. > You should be able to just add it to this thread if no other changes > are required - no need for a v2 just to address this. > > ... Hi Simon, >From reading the code and git logs I suspect this commit, which introduced icmpv6_error(): 9fb9cbb1082d [NETFILTER]: Add nf_conntrack subsystem. (introduced in: Linux v2.6.15 / 2006) Unfortunately, I was only able to reproduce it in practice on a Debian 5 / Linux 2.6.26 in a VM so far. I could boot a Debian 4 + Linux 2.6.15, but wasn't able to insert conntrack rules with ip6tables there though, even with some iptables + kernel rebuilds/reconfigure attempts. Also this related fix introduced in v2.6.29 should hint to the age of this issue: 3f9007135c1d netfilter: nf_conntrack_ipv6: don't track ICMPv6 negotiation message Which only picked/fixed a few ICMPv6 types but not ICMPv6 MRD though. tl;dr: for me this would be ok, if it were ok for others, too, that I couldn't fully bisect to it in practice... : Fixes: 9fb9cbb1082d ("[NETFILTER]: Add nf_conntrack subsystem.")