4-way Xeon and "panic: spin lock held too long."

[Krzysztof Kowalik]

Hello.

Today one of my boxes paniced with "panic: spin lock held too long."
message -- it was online for 6 hours, under rather light load.

Unfortunately, I wasn't able to get any more information, as the box got
restarted by our staff. 

Is this, anyway, a known problem (I see two people mentioning it on
freebsd-smp in May 2005) and, what's more important, how can it be
fixed?

The OS is 5.4-RELEASE-p7, the hardware:

[...]
CPU: Intel Pentium III Xeon (697.68-MHz 686-class CPU)
Origin = "GenuineIntel"  Id = 0x6a1 Stepping = 1
Features=0x387fbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP ,MTRR,PGE,MCA,CMOV,PAT,PSE36,PN,MMX,FXSR,SSE>
real memory  = 1073676288 (1023 MB)
avail memory = 1041125376 (992 MB)
ACPI APIC Table: <INTEL  SKA4    >
FreeBSD/SMP: Multiprocessor System Detected: 4 CPUs
cpu0 (BSP): APIC ID:  3
cpu1 (AP): APIC ID:  0
cpu2 (AP): APIC ID:  1
cpu3 (AP): APIC ID:  2
MADT: Forcing active-low polarity and level trigger for SCI
[...]
SMP: AP CPU #1 Launched!
SMP: AP CPU #2 Launched!
SMP: AP CPU #3 Launched!
[...]

Any ideas?

-- 
Krzysztof Kowalik               |  () ASCII Ribbon Campaign
Computer Centre, AGH UST        |  /\ Support plain text e-mail