[CHECKER] deadlock in 2.5.62 drivers/usb/host/uhci-hcd.c?

[CHECKER] deadlock in 2.5.62 drivers/usb/host/uhci-hcd.c?

[Dawson Engler]

Hi All,

there appears to be a potential locking cycle in 2.5.62's
	drivers/usb/host/uhci-hcd.c
Though it looks like its in debugging code.

Confirmation/destruction appreciated.

   <struct urb.lock (<local>:0)>-><struct uhci_hcd.complete_list_lock (<local>:0)> occurred 1 times
   <struct uhci_hcd.complete_list_lock (<local>:0)>-><struct urb.lock (<local>:0)> occurred 1 times
   Lock <struct urb.lock> is involved in <1> errors and <struct uhci_hcd.complete_list_lock> in 1

Callchain for
  <struct urb.lock (<local>:0)>-><struct uhci_hcd.complete_list_lock (<local>:0)> =

    depth = 2:
        drivers/usb/host/uhci-hcd.c:uhci_transfer_result:1507
        	spin_lock_irqsave(&urb->lock, flags);

           ->drivers/usb/host/uhci-hcd.c:uhci_transfer_result:1507
           	->uhci_transfer_result:1568
           	->end=uhci_add_complete:138:spin_lock_irq
                
                     spin_lock_irqsave(&uhci->complete_list_lock, flags);

   
Callchain for
  <struct uhci_hcd.complete_list_lock (<local>:0)>-><struct urb.lock (<local>:0)> =
    depth = 2:
        drivers/usb/host/uhci-debug.c:uhci_show_lists:395
           ->drivers/usb/host/uhci-debug.c:uhci_show_lists:395
           ->uhci_show_lists:407

        spin_lock_irqsave(&uhci->complete_list_lock, flags);

           ->end=uhci_show_urbp:328:spin_lock
           ->drivers/usb/host/uhci-debug.c:uhci_show_urbp:328

        		spin_lock(&urbp->urb->lock);