-current panics while iwm(4) is in use

[nia <nia%NetBSD.org@localhost>]

Not reproducable in 9.

db> crash> bt
_KERNEL_OPT_NARCNET() at 0
_KERNEL_OPT_ACPI_SCANPCI() at _KERNEL_OPT_ACPI_SCANPCI+0x7
sys_reboot() at sys_reboot
db_reboot_cmd() at db_reboot_cmd
db_command() at db_command+0x13a
db_command_loop() at db_command_loop+0xa6
db_trap() at db_trap+0xf9
kdb_trap() at kdb_trap+0xe1
trap() at trap+0x2c9
--- trap (number 1) ---
breakpoint() at breakpoint+0x5
vpanic() at vpanic+0x178
kern_assert() at kern_assert+0x48
mi_switch() at mi_switch+0x7dd
sleepq_block() at sleepq_block+0x17e
iwm_firmware_load_sect() at iwm_firmware_load_sect+0x1c9
iwm_load_cpu_sections_7000() at iwm_load_cpu_sections_7000+0x68
iwm_load_ucode_wait_alive() at iwm_load_ucode_wait_alive+0x648
iwm_init_hw() at iwm_init_hw+0xb3
iwm_init() at iwm_init+0x3e
ifmedia_change() at ifmedia_change+0x48
ifmedia_ioctl() at ifmedia_ioctl+0x12c
ieee80211_ioctl() at ieee80211_ioctl+0x398
iwm_ioctl() at iwm_ioctl+0x169
doifioctl() at doifioctl+0x990
sys_ioctl() at sys_ioctl+0x59c
syscall() at syscall+0x299
--- syscall (number 54) ---
734deef681ba:
db> crash> callout
    ticks  wheel               arg  func
crash: _kvm_kvatop(0)
crash: kvm_read(0x0, 16592): invalid translation (invalid level 4 PDE)