DragonFlyBSD

I got a kernel panic on my vkernel trying to ping6 another vkernel on the same host.
I might have done an incorrect network configuration, but I guess it shouldn't panic anyway.

Here is what I've done.

Two fresh vkernels with ipv6_enable=yes in rc.conf started with:

/boot/kernel/kernel -m 1g -r /vhost/vm0.img -I /var/run/vknet

and

/boot/kernel/kernel -m 1g -r /vhost/vm1.img -I /var/run/vknet

vknetd is executed as "/usr/sbin/vknetd -U -t tap0".

I run the following version of DragonFly (on all three machines: host and both vkernels):

1. uname -a
   DragonFly 5.8-RELEASE DragonFly v5.8.0rc1.28.g3e3e37-RELEASE #2: Sun Mar 1 17:46:44 CET 2020 root@fi.zta.lk:/usr/obj/usr/src/sys/VKERNEL64 x86_64

On one of the vkernels I first check that I can ping the other one:

1. ping6 fe80::201:71ff:fe0c:f607%vke0
   PING6 fe80::201:68ff:fef8:f5f8%vke0 --> fe80::201:71ff:fe0c:f607%vke0
   16 bytes from fe80::201:71ff:fe0c:f607%vke0, icmp_seq=1 hlim=64 time=0.371 ms
   16 bytes from fe80::201:71ff:fe0c:f607%vke0, icmp_seq=2 hlim=64 time=0.262 ms
   ^C
   --- fe80::201:71ff:fe0c:f607%vke0 ping6 statistics ---
   3 packets transmitted, 2 packets received, 33.3% packet loss
   round-trip min/avg/max/std-dev = 0.262/0.317/0.371/0.054 ms

Then do the following to get the panic:

1. route add -inet6 fe80::201:71ff:fe0c:f607 -iface vke0
   add host fe80::201:71ff:fe0c:f607: gateway vke0

1. ping6 fe80::201:71ff:fe0c:f607
   PING6 fe80::201:68ff:fef8:f5f8%vke0 --> fe80::201:71ff:fe0c:f607
   panic: assertion "sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0" failed in nd6_resolve at /usr/src/sys/netinet6/nd6.c:2031
   cpuid = 0
   Trace beginning at frame 0x8026783680
   nd6_resolve() at 0x60ab55
   nd6_resolve() at 0x60ab55
   ether_output_frame() at 0x59427c
   ip6_output() at 0x6026a1
   rip6_output() at 0x610e9f
   rip6_output() at 0x611446
   Debugger("panic")

CPU0 stopping CPUs: 0x0000000000000002
stopped
Stopped at 0x70bde9: movb $0,0xa0c83c(%rip)
db> trace
Debugger() at 0x70bde9
panic() at 0x4c7710
nd6_resolve() at 0x60ab55
ether_output_frame() at 0x59427c
ip6_output() at 0x6026a1
rip6_output() at 0x610e9f
rip6_output() at 0x611446
netmsg_sync_handler() at 0x5a1739

--
Aleksej Lebedev