We have been having rampant issues using Dummynet's IPv6 support, and it's been causing panic's every 24-48 hours. Enabled WITNESS and BREAK_TO_DEBUGGER, and this is the result. -=- lock order reversal: (sleepable after non-sleepable) 1st 0xffffff034809c900 rtentry (rtentry) @ /usr/src/sys/netinet6/ip6_input.c:501 2nd 0xffffffff808dda70 user map (user map) @ /usr/src/sys/vm/vm_map.c:3074 KDB: stack backtrace: witness_checkorder() at witness_checkorder+0x48a _sx_xlock() at _sx_xlock+0x3e vm_map_lookup() at vm_map_lookup+0x44 vm_fault() at vm_fault+0xba trap_pfault() at trap_pfault+0x13c trap() at trap+0x1bd calltrap() at calltrap+0x5 --- trap 0xc, rip = 0xffffffff804c41f7, rsp = 0xffffffffbdf0da60, rbp 0xffffffffbdf0daf0 --- ip6_input() at ip6_input+0xa07 dummynet_send() at dummynet_send+0x17e dummynet() at dummynet+0x21a softclock() at softclock+0x19a ithread_loop() at ithread_loop+0x132 fork_exit() at fork_exit+0x87 fork_trampoline() at fork_trampoline+0xe --- trap 0, rip = 0, rsp = 0xffffffffbdf0dd00, rbp = 0 --- Fatal trap 12: page fault while in kernel mode cpuid = 2; apic id = 06 fault virtual address = 0x98 fault code = supervisor read, page not present instruction pointer = 0x8:0xffffffff804c41f7 stack pointer = 0x10:0xffffffffbdf0da60 frame pointer = 0x10:0xffffffffbdf0daf0 code segment = base 0x0, limit 0xfffff, type 0x1b = DPL 0, pres 1, long 1, def32 0, gran 1 processor eflags = interrupt enabled, resume, IOPL = 0 current process = 15 (swi4: clock sio) [thread pid 15 tid 100009 ] Stopped at ip6_input+0xa07: movq 0x98(%rdi),%rax db> tr Tracing pid 15 tid 100009 td 0xffffff040ff3b000 ip6_input() at ip6_input+0xa07 dummynet_send() at dummynet_send+0x17e dummynet() at dummynet+0x21a softclock() at softclock+0x19a ithread_loop() at ithread_loop+0x132 fork_exit() at fork_exit+0x87 fork_trampoline() at fork_trampoline+0xe --- trap 0, rip = 0, rsp = 0xffffffffbdf0dd00, rbp = 0 --- -=- Any ideas how to proceed? Best Wishes - Peter