On FreeBSD 10.3-RELEASE running with two digium cards and working fine: wctdm24xxp0@pci0:7:0:0: class=0x020000 card=0x2400d161 chip=0x2400d161 rev=0x11 hdr=0x00 te12xp0@pci0:7:2:0: class=0x020000 card=0x8001d161 chip=0x8001d161 rev=0x11 hdr=0x00 when we shuting down this system halts: ... Stopping asterisk dahdi wctdm24xxp0: <6>Freed a Wildcard dahdi: disable_span: span 2 Fatal trap 12: page fault while in kernel mode cpuid = 1; apic id = 01 fault virtual address = 0x28 fault code = supervisor read data, page not present instruction pointer = 0x20:0xffffffff80937699 stack pointer = 0x28:0xfffffe00506817e0 frame pointer = 0x28:0xfffffe0050681800 code segment = base rx0, limit 0xfffff, type 0x1b = DPL 0, pres 1, long 1, def32 0, gran 1 processor eflags = interrupt enabled, resume, IOPL = 0 current process = 931 (kldunload) trap number = 12 panic: page fault cpuid = 1 KDB: stack backtrace: #0 0xffffffff8098e390 at kdb_backtrace+0x60 #1 0xffffffff80951066 at vpanic+0x126 #2 0xffffffff80950f33 at panic+0x43 #3 0xffffffff80d55f7b at trap_fatal+0x36b #4 0xffffffff80d5627d at trap_pfault+0x2ed #5 0xffffffff80d558fa at trap+0x47a #6 0xffffffff80d3b8d2 at calltrap+0x8 #7 0xffffffff81c7cf61 at wctdm_back_out_gracefully+0x401 #8 0xffffffff81c7cb4d at wctdm_release+0xad #9 0xffffffff81c7ca07 at wctdm_remove_one+0x2a7 #10 0xffffffff81c7c748 at wctdm_device_detach+0x38 #11 0xffffffff80983062 at device_detach+0x52 #12 0xffffffff809828bb at devclass_driver_deleted+0x6b #13 0xffffffff809827df at devclass_delete_driver+0x7f #14 0xffffffff80987413 at driver_module_handler+0x43 #15 0xffffffff80935c8e at module_unload+0x4e #16 0xffffffff8092b2da at linker_file_unload+0x29a #17 0xffffffff8092c393 at kern_kldunload+0xd3 Uptime: 7m58s