todays dom0 kernel going splat via fdcattach

["S.P.Zeidler" <spz%NetBSD.org@localhost>]

Hi,

it said:
[other boot messages elided]
[   1.0000030] fdc0 at isa0 port 0x3f0-0x3f7 irq 6 drq 2
[   1.0000030] uvm_fault(0xffffffff80d12860, 0x0, 1) -> e
[   1.0000030] fatal page fault in supervisor mode
[   1.0000030] trap type 6 code 0 rip 0xffffffff8021d6f8 cs 0xe030 rflags 0x10286 cr2 0x10 ilevel 0x8 rsp 0xffffffff810722c0
[   1.0000030] curlwp 0xffffffff80b47a80 pid 0.0 lowest kstack 0xffffffff8106e2c0
kernel: page fault trap, code=0
Stopped in pid 0.0 (system) at  netbsd:bus_dmamap_create+0x1a:  testb   $0x1,10(
%rdi)
bus_dmamap_create() at netbsd:bus_dmamap_create+0x1a
_isa_dmamap_create() at netbsd:_isa_dmamap_create+0x4b
fdcattach() at netbsd:fdcattach+0xb2
fdc_isa_attach() at netbsd:fdc_isa_attach+0xfe
config_attach_internal() at netbsd:config_attach_internal+0x197
config_attach() at netbsd:config_attach+0x49
isasearch() at netbsd:isasearch+0x1ee
mapply() at netbsd:mapply+0x23
config_search_internal() at netbsd:config_search_internal+0x179
config_search() at netbsd:config_search+0x7d
isarescan() at netbsd:isarescan+0xb4
isaattach() at netbsd:isaattach+0xad
config_attach_internal() at netbsd:config_attach_internal+0x197
config_found() at netbsd:config_found+0xc1
pcibrescan() at netbsd:pcibrescan+0xc1
pcib_callback() at netbsd:pcib_callback+0x12
config_process_deferred() at netbsd:config_process_deferred+0xbc
config_attach_internal() at netbsd:config_attach_internal+0x225
config_found() at netbsd:config_found+0xc1
mp_pci_scan() at netbsd:mp_pci_scan+0xd6
hypervisor_attach() at netbsd:hypervisor_attach+0x56c
config_attach_internal() at netbsd:config_attach_internal+0x197
config_found() at netbsd:config_found+0xc1
xen_mainbus_attach() at netbsd:xen_mainbus_attach+0x9c
mainbus_attach() at netbsd:mainbus_attach+0x4a
config_attach_internal() at netbsd:config_attach_internal+0x197
config_rootfound() at netbsd:config_rootfound+0x77
cpu_configure() at netbsd:cpu_configure+0x25
main() at netbsd:main+0x32c
ds          0
es          2a40
fs          6970
gs          6f69
rdi         0
rsi         0
rbp         ffffffff81072330
rbx         0
rdx         1
rcx         0
rax         ffffffff80c81be0    x86_isa_chipset+0x40
r8          0
r9          3
r10         0
r11         ffffffff80b00394    cpu_info_primary+0x694
r12         0
r13         ffffb680025ad940
r14         3
r15         ffffffff80b559c0    cfdata+0x3720
rip         ffffffff8021d6f8    bus_dmamap_create+0x1a
cs          e030
rflags      10286
rsp         ffffffff810722c0
ss          e02b
netbsd:bus_dmamap_create+0x1a:  testb   $0x1,10(%rdi)

This specific boot is with a 4.15 xenkernel but it showed the same
behaviour with a 4.8 xenkernel.

regards,
	spz