panic: mutex isp not owned at ../../../kern/kern_mutex.c:206

[Kris Kennaway]

Another panic when booting an e4500 running CURRENT:

sbus0: <SUNW,socal> mem 0x10000-0x20017 irq 162 type socal (no driver 
attached)
isp0 mem 0x10000-0x1044f irq 139 on sbus0
isp0: [ITHREAD]
panic: mutex isp not owned at ../../../kern/kern_mutex.c:206
cpuid = 0
KDB: enter: panic
[thread pid 0 tid 0 ]
Stopped at      kdb_enter+0x68: ta              %xcc, 1
db> wh
Tracing pid 0 tid 0 td 0xc0749280
panic() at panic+0x204
_mtx_assert() at _mtx_assert+0xac
_mtx_unlock_flags() at _mtx_unlock_flags+0x12c
isp_sbus_mbxdma() at isp_sbus_mbxdma+0x38
isp_reset() at isp_reset+0x214
isp_sbus_attach() at isp_sbus_attach+0x7a0
device_attach() at device_attach+0x4a4
device_probe_and_attach() at device_probe_and_attach+0x188
bus_generic_attach() at bus_generic_attach+0x10
sbus_attach() at sbus_attach+0x111c
device_attach() at device_attach+0x4a4
device_probe_and_attach() at device_probe_and_attach+0x188
bus_generic_attach() at bus_generic_attach+0x10
nexus_attach() at nexus_attach+0x4fc
device_attach() at device_attach+0x4a4
device_probe_and_attach() at device_probe_and_attach+0x188
root_bus_configure() at root_bus_configure+0x28
configure() at configure+0x4
mi_startup() at mi_startup+0x18c
btext() at btext+0x34

Kris