panic: mtx_lock() of spin mutex (null) @ sys/netinet/frag6.c:682 cpuid = 0 kdb_backtrace+0x37 panic+0x1d1 _mtx_lock_flags+0x72 frag6_slowtimo+0x26 pfslowtimo+0x5a softclock+0x1c0 ithread_loop+0x179 fork_exit+0xe9 fork_trampoline+0xe This is FreeBSD/amd64 from today's sources of about 30 minutes ago. -- Steve