r314708: panic: Assertion err == 0 failed at /usr/src/sys/net/iflib.c:2241

This came up at shutdown in r314708. I don't yet know if I will have a
core to diagnose.

> panic: Assertion err == 0 failed at /usr/src/sys/net/iflib.c:2241
> cpuid = 0
> KDB: stack backtrace:
> db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe349a7f9940
> vpanic() at vpanic+0x186/frame 0xfffffe349a7f99c0
> _kassert_panic() at _kassert_panic+0x12f/frame 0xfffffe349a7f9a40
> _task_fn_rx() at _task_fn_rx+0x19d/frame 0xfffffe349a7f9b20
> gtaskqueue_run_locked() at gtaskqueue_run_locked+0x139/frame 0xfffffe349a7f9b80
> gtaskqueue_thread_loop() at gtaskqueue_thread_loop+0x88/frame 0xfffffe349a7f9bb0
> fork_exit() at fork_exit+0x84/frame 0xfffffe349a7f9bf0
> fork_trampoline() at fork_trampoline+0xe/frame 0xfffffe349a7f9bf0
> --- trap 0, rip = 0, rsp = 0, rbp = 0 ---
> KDB: enter: panic
> [ thread pid 0 tid 100038 ]
> Stopped at      kdb_enter+0x3b: movq    $0,kdb_why

-- 
Regards,
Bryan Drewery