dfrig_nat[go3]: BEFORE dispatch: ch=0xffffffff82601140 ch->dma=0 (NULL means DMA unavailable, ata-dma.c:153) atadev->unit=0 dfrig_nat[go3]: dispatching production ata_national_setmode(dev, ATA_PIO_MAX) (verbatim #included copy) Fatal user address access from kernel mode from sysctl at ffffffff826004b5 Fatal trap 12: page fault while in kernel mode cpuid = 1; lapic id = 1 fault virtual address = 0x58 fault code = supervisor write data, page not present instruction pointer = 0x8:0xffffffff826004b5 stack pointer = 0x10:0xfffff801180ab6d8 frame pointer = 0x10:0xfffff801180ab728 code segment = base 0x0, limit 0xfffff, type 0x1b = DPL 0, pres 1, long 0, def32 0, gran 1 processor eflags = interrupt enabled, resume, IOPL = 0 current process = 1013 current thread = pri 6 kernel: type 12 trap, code=2 CPU1 stopping CPUs: 0x0000003d stopped Stopped at ata_national_setmode+0x65: movl $0x10,0x58(%rax) db>