# verbatim transcript, guest root shell, stock kernel
/tmp/dfv3 drift
(config pipe ok / flowset ok / flowset ok lines as in other runs)
[+] sent 2 x 1400B udp pkt(s) -> 127.0.0.1:3001     # flow A: 1 stays backlogged
[+] del pipe ok                                      # purge; backlogged stays 1
[+] config pipe ok                                   # recreate pipe: sum=0
[+] sent 2 x 1400B udp pkt(s) -> 127.0.0.1:3002     # flow B: backlogged=1+1, sum=1
[+] del flowset ok                                   # sum -= 1*2 -> sum = -1
[+] sent 1 x 28B udp pkt(s) -> 127.0.0.1:4001       # flow C: sum += 1 -> 0
[*] waiting for wfq fire -> divide error...
(ssh session dies: kernel panics ~1.4s later when the wfq event fires)
# serial console (dfbsd-qemu/vm.sh log):
DUMMYNET initialized (011031)
++ ref to pipe 1 from fs 300        <-- dn_unref_pipe_cb kprintf (ip_dummynet3.c:1624):
                                        proof the pipe-deletion purge path ran
Fatal trap 18: integer divide fault while in kernel mode
cpuid = 0; lapic id = 0
instruction pointer	= 0x8:0xffffffff8264a441
stack pointer	        = 0x10:0xfffff8008d1f89c0
frame pointer	        = 0x10:0xfffff8008d1f8a20
current process		= Idle
kernel: type 18 trap, code=0
CPU0 stopping CPUs: 0x0000003e
Stopped at      ready_event_wfq+0xd1:   divq    %rcx,%eax
db>