When running some kvm testing on 2.6.27-rc4 with various kernel debug
options enabled, I hit the MAX_LOCK_DEPTH limit of 48:
[ 30.670253] uhci_hcd 0000:00:1d.2: FGR not stopped yet!
[ 30.701773] uhci_hcd 0000:00:1d.1: FGR not stopped yet!
[ 30.733533] uhci_hcd 0000:00:1d.0: FGR not stopped yet!
[ 30.765379] uhci_hcd 0000:00:1a.2: FGR not stopped yet!
[ 30.797253] uhci_hcd 0000:00:1a.0: FGR not stopped yet!
[ 115.469934] uhci_hcd 0000:00:1d.0: FGR not stopped yet!
[ 184.507012] Hangcheck: hangcheck value past margin!
[ 245.448004] BUG: MAX_LOCK_DEPTH too low!
[ 245.448004] turning off the locking correctness validator.
[ 260.937296] kvm: emulating exchange as write
[ 364.507049] Hangcheck: hangcheck value past margin!
[ 544.454998] Hangcheck: hangcheck value past margin!
[ 724.507006] Hangcheck: hangcheck value past margin!
Maybe the result of a particular path abusing a lock (ie a bug) even?
Daniel
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Daniel J Blueman