panic just seen during boot

I'm re-sup-ing now to see if this has been fixed....
but if anyone thinks this looks like something they
are working with....
(using LOCK_PROFILING)

[...]
cpu0: <ACPI CPU> on acpi0
cpu1: <ACPI CPU> on acpi0
cpu2: <ACPI CPU> on acpi0
cpu3: <ACPI CPU> on acpi0
pcib0: <ACPI Host-PCI bridge> port 0xcf8-0xcff on acpi0
pci0: <ACPI PCI bus> on pcib0
panic: mtx_lock() of spin mutex  _at_ ../../../kern/kern_sx.c:172
cpuid = 0
KDB: enter: panic
[thread pid 0 tid 0 ]
Stopped at      kdb_enter+0x2b: nop
db>
db> tr
Tracing pid 0 tid 0 td 0xc075c6c8
kdb_enter(c06c926e) at kdb_enter+0x2b
panic(c06c8311,c5f3e640,c06c9a68,ac,0,...) at panic+0x11c
_mtx_lock_flags(c5f3e680,0,c06c9a68,ac) at _mtx_lock_flags+0x78
_sx_xlock(c090aa40,c0904c02,dd,c06925c2,ff,...) at _sx_xlock+0x34
acpi_pcib_route_interrupt(c5fb8600,c5fce300,1,c5fc5df4,c5fb8600,...) at 
acpi_pcib_route_interrupt+0x2e
acpi_pcib_acpi_route_interrupt(c5fb8600,c5fce300,1) at 
acpi_pcib_acpi_route_interrupt+0x1d
pci_assign_interrupt_method(c5fce880,c5fce300) at 
pci_assign_interrupt_method+0x58
pci_assign_interrupt(c5fce880,c5fce300,1) at pci_assign_interrupt+0xc0
pci_add_resources(c5fce880,c5fce300,0,0,c5f85b00,...) at 
pci_add_resources+0x21d
pci_add_child(c5fce880,c5f85b00) at pci_add_child+0x52
pci_add_children(c5fce880,0,cc,c0719b78,0,...) at pci_add_children+0x10a
acpi_pci_attach(c5fce880) at acpi_pci_attach+0x66
device_attach(c5fce880,c5fcead0,c5fce880,0,c5fb8600,...) at 
device_attach+0x58
device_probe_and_attach(c5fce880) at device_probe_and_attach+0xe0
bus_generic_attach(c5fb8600,c5fb8600,0,c5ed7d60,c5fc5de0,...) at 
bus_generic_attach+0x16
acpi_pcib_attach(c5fb8600,c5fc5df4,0,c0c20c40,c054c078,...) at 
acpi_pcib_attach+0x12f
acpi_pcib_acpi_attach(c5fb8600) at acpi_pcib_acpi_attach+0xcf
device_attach(c5fb8600,c0c20c88,c5fb8600,c5fc1a40,c5fb9400,...) at 
device_attach+0x58
device_probe_and_attach(c5fb8600) at device_probe_and_attach+0xe0
bus_generic_attach(c5fb9400,ef,e0,c5fc5248,4,...) at bus_generic_attach+0x16
acpi_attach(c5fb9400) at acpi_attach+0x5f6
device_attach(c5fb9400,0,c5fb9400,c5f4b100,0,...) at device_attach+0x58
device_probe_and_attach(c5fb9400) at device_probe_and_attach+0xe0
bus_generic_attach(c5f4b100,c5f4b100,c5f4b100,c0c20d40,c0547348,...) at 
bus_generic_attach+0x16
nexus_attach(c5f4b100) at nexus_attach+0x13
device_attach(c5f4b100,0,c5f4b100,c0718804,c28000,...) at device_attach+0x58
device_probe_and_attach(c5f4b100) at device_probe_and_attach+0xe0
root_bus_configure(c0c20d88,c0500586,0,c1ec00,c1e000,...) at 
root_bus_configure+0x16
configure(0,c1ec00,c1e000,0,c0434b95,...) at configure+0x9
mi_startup() at mi_startup+0x96
begin() at begin+0x2c
db>