panic: spin lock held too long (reasonable load)

Hi

I got this about an hour ago, maybe 10 minutes into a 'make world
-j8' on my SMP system.  I'll reproduce the panic and drop into the
debugger if possible if someone is willing to tell me what information
appart from this backtrace will be helpful.

spin lock sleepq chain held by 0xc0fc2540 for > 5 seconds
panic: spin lock held too long
cpuid = 1; 
Stack backtrace:
backtrace(100,c111ba80,3938700,c065069c,4) at backtrace+0x12
panic(c05fee1c,c05fedf3,c0600e3a,c0fc2540,c0650698) at panic+0x11e
_mtx_lock_spin(c065069c,0,0,0) at _mtx_lock_spin+0x80
sleepq_lookup(c06483a0,c14dc370,d0f7ec48,c14de2a0,ffffffff) at sleepq_lookup+0x6
0
sleepq_broadcast(c06483a0,0,ffffffff,d0f7ec50,c04cf15c) at sleepq_broadcast+0x11
wakeup(c06483a0,d0f7ec64,c04e3ea2,c14de2a0,c14de2a0) at wakeup+0xf
setrunnable(c14de2a0) at setrunnable+0x78
sleepq_resume_thread(c14de2a0,ffffffff) at sleepq_resume_thread+0x9a
sleepq_broadcast(c14dc370,0,ffffffff,d0f7ecdc,c04b090e) at sleepq_broadcast+0xa7
wakeup(c14dc370) at wakeup+0xf
exit1(c111ba80,0,d0f7ed40,c05ca81f,c111ba80) at exit1+0x130e
exit1(c111ba80,d0f7ed14,1,4,282) at exit1
syscall(2f,2f,2f,bfbfe86c,bfbfe8a0) at syscall+0x283
Xint0x80_syscall() at Xint0x80_syscall+0x1f
--- syscall (1), eip = 0x8269667, esp = 0xbfbfe818, ebp = 0xbfbfe834 ---
boot() called on cpu#1

syncing disks, buffers remaining... spin lock sched lock held by 0xc111ba80 for 
> 5 seconds
spin lock sleepq chain held by 0xc0fc2540 for > 5 seconds
panic: spin lock held too long
cpuid = 1; 
boot() called on cpu#1
Uptime: 1h47m35s
spin lock sleepq chain held by 0xc0fc2540 for > 5 seconds
panic: spin lock held too long
cpuid = 1; 
boot() called on cpu#1
Uptime: 1h47m35s
spin lock sleepq chain held by 0xc0fc2540 for > 5 seconds
panic: spin lock held too long
cpuid = 1; 
boot() called on cpu#1
Uptime: 1h47m35s
spin lock sleepq chain held by 0xc0fc2540 for > 5 seconds
panic: spin lock held too long
cpuid = 1; 
boot() called on cpu#1
Uptime: 1h47m35s

Fatal double fault:
eip = 0xc05d5175
esp = 0xd0f7cfd8
ebp = 0xd0f7d05c
cpuid = 1; apic id = 01
panic: double fault
cpuid = 1; 
boot() called on cpu#1
Uptime: 1h47m35s
spin lock sleepq chain held by 0xc0fc2540 for > 5 seconds
panic: spin lock held too long
cpuid = 1; 
boot() called on cpu#1
Uptime: 1h47m35s

--
Ian Freislich