I try to use a Raspi4 as DSL router. That works fine with mpd5. For IPv6 I use dhcpcd but when I try my setup with CURRENT the kernel panics (with Raspi3 or Raspi4) when I start dhcpcd. With a Raspi3 and 12.1 the same setup works fine. Here the panic: panic: prefix 0xffffa000060c6000 has referencing addresses cpuid = 0 time = 1607078839 KDB: stack backtrace: db_trace_self() at db_trace_self_wrapper+0x30 pc = 0xffff00000055ae28 lr = 0xffff00000005eb10 sp = 0xffff00061d8dae40 fp = 0xffff00061d8db050 db_trace_self_wrapper() at vpanic+0x194 pc = 0xffff00000005eb10 lr = 0xffff00000029346c sp = 0xffff00061d8db060 fp = 0xffff00061d8db0e0 vpanic() at panic+0x44 pc = 0xffff00000029346c lr = 0xffff0000002934f8 sp = 0xffff00061d8db0f0 fp = 0xffff00061d8db170 panic() at nd6_prefix_del+0x224 pc = 0xffff0000002934f8 lr = 0xffff00000052f1dc sp = 0xffff00061d8db180 fp = 0xffff00061d8db2d0 nd6_prefix_del() at nd6_ioctl+0x54c pc = 0xffff00000052f1dc lr = 0xffff00000052d6dc sp = 0xffff00061d8db2e0 fp = 0xffff00061d8db310 nd6_ioctl() at ifioctl+0x528 pc = 0xffff00000052d6dc lr = 0xffff0000005729dc sp = 0xffff00061d8db320 fp = 0xffff00061d8db3d0 ifioctl() at kern_ioctl+0x2ec pc = 0xffff0000005729dc lr = 0xffff00000055c874 sp = 0xffff00061d8db3e0 fp = 0xffff00061d8db4f0 kern_ioctl() at sys_ioctl+0x144 pc = 0xffff00000055c874 lr = 0xffff00005996674c sp = 0xffff00061d8db500 fp = 0xffff00061d8db580 sys_ioctl() at do_el0_sync+0x454 pc = 0xffff00005996674c lr = 0xffff00000039e000 sp = 0xffff00061d8db590 fp = 0xffff00061d8db5b0 do_el0_sync() at handle_el0_sync+0x90 pc = 0xffff00000039e000 lr = 0xffff000000266a68 sp = 0xffff00061d8db5c0 fp = 0xffff00061d8db8e0 handle_el0_sync() at 0x251e84 pc = 0xffff000000266a68 lr = 0xffff000000268120 sp = 0xffff00061d8db8f0 fp = 0xffff00061d8db920 KDB: enter: panic [ thread pid 1260 tid 100123 ] Stopped at 0x40459e44 (the values of the registers are not correct since I only had a screenshot of the panic and needed to type it in by hand and used another panic as template, the rest is correct though)
Looks like you're triggering this KASSERT http://fxr.watson.org/fxr/source/netinet6/nd6_rtr.c#L1309 It's likely that the kernel received a RA before dhcpcd had a chance to take over. Ensure that FreeBSD rc.conf and interface setup has zero IPv6 config and that net.inet6.ip6.accept_rtadv is 0. Then you should not hit that KASSERT.
with the release of the freebsd 13 ISO of alpha 2 the bug is not there anymore.