On Mon, 17 Aug 2015, Peter Zijlstra wrote:

> On Mon, Aug 17, 2015 at 10:32:20AM -0400, Alan Stern wrote:
> > On Mon, 17 Aug 2015, Peter Chen wrote:
> > 
> > > Hi Alan,
> > > 
> > > When run "echo 105  > 
> > > /sys/bus/platform/devices/ci_hdrc.1/uframe_periodic_max",
> > > if lockdep check is enabled, there is below dump, I am afraid it can't
> > > find how to fix it, the warning shows the key is not persistent.
> > > (see line 757, kernel/locking/lockdep.c).
> > > 
> > > 
> > > [   70.190430] INFO: trying to register non-static key.
> > > [   70.195437] the code is fine but needs lockdep annotation.
> > > [   70.200939] turning off the locking correctness validator.
> 
> > I don't understand this either.
> > 
> > Maybe Peter Z. can help.  This dump is triggered by the
> > spin_lock_irqsave() call in
> > drivers/usb/host/ehci-sysfs.c:store_uframe_periodic_max().  That
> > function doesn't appear to be unusual in any way.
> 
> Can it happen this code is called before a corresponding
> spin_lock_init()?

No; the spinlock gets initialized in ehci_init() long before the sysfs
file is registered.

> Alternatively, memory corruption is an option. If something stomped on
> the lockdep state you can trigger this I suppose.

Can you suggest any particular debugging printk for Peter C. to try?

Alan Stern

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