'panic: spin lock held too long' at boot

[Kris Kennaway]

The following has happened twice recently while booting 6.0 on a
12-processor e4500:

[...]
Waiting 8 seconds for SCSI devices to settle
SMP: AP CPU #11 Launched!
SMP: AP CPU #10 Launched!
SMP: AP CPU #9 Launched!
SMP: AP CPU #8 Launched!
SMP: AP CPU #7 Launched!
SMP: AP CPU #6 Launched!
SMP: AP CPU #5 Launched!
SMP: AP CPU #4 Launched!
SMP: AP CPU #3 Launched!
SMP: AP CPU #2 Launched!
SMP: AP CPU #1 Launched!
panic: spin lock held too long0xffffff813e774730 foor >5 seecons
cpuid = 11
KDB: enter: panic
[hangs]

Any ideas?

Kris
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